Pinned reply to many comments: I do not state in any part of this video that rim brakes are superior. Im saying road discs don't seem to be suitably sized for the thermal load. But hell they still work better than rim in the pissing rain on a 10km downhill. If i had a component company, i wouldn't have released disc road brakes in this state of development. They're not good enough. Too many inconsistencies, noise, too little cooling.
The question now is. How many of us normally ride in the rain and worse yet, downhill? I never do. And neither do most people out there. Meanwhile, for that hypothetical one-off you have to put up with all these disadvantages 99.99% of the time. But hey! Let people ride whatever they want.
@@joseluisrodriguezvazquez6082 Completely agree, I do regularly descend at speeds of 50mph to 60mph and in the dry rim is King in the wet I don't care as I have no intention of relying on such optimal braking performance as my tyres will let me down before rim or disc brakes will. I swap between rim and disc, I really like both but as a complete package/race bike rim edges it imo.
Also, probably the reason why Chris says those problems is that I heard he trains for the climbs on relatively flat roads by slightly breaking while riding
Weight weentard here. I remain unapologetic for demanding lightweight shit, haha. I think the variance of system weight is also hilarious. I weigh 51kg with a 7kg disc brake bike. System weight of 58kg. There are 107kg guys out there riding 9kg bikes; 116kg system weight. Most of the time they're equipped with the same braking systems as me. That would be like a pickup truck having the same brakes as a Mini, it just ain't gonna work. The industry has convinced you that you really do need 3 different depth of wheel to suit every occasion; but a 50kg and a 100kg guy can use the same brake levers and calipers no problemo.
Well said. To be fair, It's not just the weenie demand in itself, it's also the brands bombarding everyone with 'Lighter And Stiffer!' each year, for the last 20 years.
I don't want lighter and stiffer, I just want stiffer. I can remove 5lb off myself for free. Also if I, or other people cared about weight this much then deep section wheels wouldn't exist
@@YuriThorpe deeper rims directly correlate with aero advantages that outweigh weight disadvantages on most roads. Heavier, larger discs and calipers only correlate with better braking at the expense of both weight and aero.
@@SurpriseMeJT the stiffness in wheels comes from the tension and the bracing angle of the spoke not the shape of the spoke (i assume of course you're referring to bladed vs traditional plain gauge or butted spokes.)
@@jonnythelegs2597 The number of spokes matters too. I'd love to see the science on the lateral rigidity of bladed vs round. I've built the majority of my own wheels for 20 years and I don't quite buy the simplistic notion that spoke shape has zero influence on lateral wheel stiffness.
That scooter analogy is a damn good wakeup call. Total system weight of road bike + rider is in the range of 50-100 kg. Total system weight of scooter is around 150-300 kg. Rotors on even a little 150 cc scooter have significantly more thermal mass than on your weight weenie bike, even though they max out at about 75kph. We're putting big demands on our lightweight road bikes that's for sure
I'm not concerned by brake setup weight but I want a system that works without rub, noise, etc. The industry is forcing my next road bike option to only be a disc before they've solved these problems. I have discs on my MTB and gravel bike but don't need them on my road bike.
Exactly, the freaking rubbing and weird noises can be a nightmare, in my Mtb every time the pads are a little over 50% worn the rubbing nightmare starts and it's something I really don't want in my roadbike. The positive side though is better breaking when the pavement is wet so I don't know, eventually I guess I will end up with discs, besides last week I was looking at new bikes and like 70% of the new models use discs now.
It’s really because people want carbon rims, the only solution to personal injury lawsuits was to resort to a belt and suspenders solution, instead of staying or going back to alloy. That’s all they can do. The problems with disc brakes even my Shimano ones, who knows when they will be eliminated. Autos had same issues probably for several decades before finally getting rid of them, namely squealing. I’ll never ever ride carbon rims for safety concerns.
I live in the alps and am regularly doing descents of between 500 metres and 1000 metres on road and mountain bike. The road descents are completed a lot quicker and the braking requires much greater deceleration. Typically 70kph to 30kph for a hairpin in just 20 metres. The heat stress on the brakes is enormous. I bought a new bike with disc brakes and whilst there have been some clear advantages, sometimes the brake behaviour is appalling with a lot of noise and vibration caused by the heat. And the cost in replacement brake pads and discs is quite large compared with rim brakes.
I would have thought that the cost of pads is tiny compared to the cost of the bike.... Maybe don’t try to stop within 20 metres to reduce the stress? I gather you didn’t brake as late when in rim brakes, and it never bothered you. Discs aren’t an invitation to brake as late as possible in my opinion...
@@patrickparisienne1917 it is clearly one of the advantages, and one of the reasons to take disc brakes for racing. Although, it is hard to say if there was an advantage of discs in big races in last years.
Maybe try a parachute? TBH, I have carbon rim brakes and there's no way I would take it through a hilly section without having deep experience on that section beforehand. Given my motorcycling experience, I'd much rather be on discs in the hills.
@@in4merATP I agree discs are more efficient than rim, but unless you are racing, there is no need to push the brakes to their limits all the time. If you stress any mechanical components there cannot be complaint when there are problems. Bike manufacturers should turn to Motorsport brake specialists like a Rambo, Alcon and AP who have the experience, detailed knowledge, and the budget to have sorted these problems before. The problem is no one will want to pay for ceramic based discs, and the fact that they will be thicker, needing different calipers...
Was cycling the other day on my mate's bike, borrowed his tarmac with dura ace callipers on dura ace aluminium braking surface wheels. Car pulled out in front of me, pulled the brakes, nothing happened. If the car didn't stop I would have been through his door window. Disc brakes at least work.
Thats the other issue. getting rim brake sto actually work means eithe rrubbing OR supe rsoft rubbe rthats no good for extended use. I used to run brakes on my BMX bikes which were all rim brakes and getting them so you could do stoppies or rear taps was a nightmare. Braking power of rim brake sis ajoke and onc eyou pick up speed in some case you can't actually stop or even slow down, at best you can stop acquiring speed!
Ineos seem to be ok, last of the rim brake pro teams going down mountains, also every road cyclist pre 2010 managed to stop? Maybe you don’t know the bike / it wasn’t setup correctly / you need to start on hand grippers to increase your grip strength?
@@MrHcharles I agree I'm not used to rim brakes anymore but I did used to ride them, i remember when a van pulled out on me once and i pulled the levers too hard and double skidded, almost hitting the side. Pros are lucky because when they race they have both lanes and knowledge that no car will be there :/ I hope i set thr brakes up right, I've been a mechanic for a few years 😅
I started cycling on mountain bikes, back in the cantilever and v-brake days. I understand roadies like rim brakes for several reasons and that today’s systems are much better than the crappy ones I had on my bike 20 years ago...but I still like disc brakes on my road bike...
Same.... I missed the start of disk brakes on MTB's in the early 90's and put up with crappy V brakes for many years. When I bought a new roadie in 2015, I was happy to wait a couple of months to get a disk brake roadie. I am a bit of a zealot about them though...
@@richardhaselwood9478 If you think v-brakes are crappy you definitely need to try some cantilevers. For a while after disks were available, professional DH racers were still running XTR v-brakes on the front of their bikes, quite simply because they were still more powerful than any other option.
@@peglor I am old enough to remember what passed for "Downhill bikes" back in the 90's. Memories of reading an MTB mag (Australian) about some racers who raced XC and DH on the same bike. These bikes had V brakes of course :)
They deserve to be recalled once they sort these issues out, especially considering they don’t meet market demands, except in weight which IS an infection, well put. We(the Industry/Buyers)need to back off the wave and in so doing bring back into focus the simplicity and joy that cycling IS.
What I've been waiting to hear but not want the bike industry wants you to hear. Thanks for the concise analysis!
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If i was a roadie, i would probably still use disc brakes, but with a nice big rotor. Probably just as good for a regular guy, but i won't have to trash a wheel from wearing out the rims.
Physics always compels a reckoning. There is another design response to the heat dissipation, mechanical advantage conundrum. Larger discs. Oops, a little extra weight then. Well, two out of three ain't bad.
Froomes team is sponsored by SwissStop. Their discs are not very good compared to Shimano, so some of his issues could be solved by not using bad discs
Glad I kept my Merida Team bike (rim brake) and resisted the disc band wagon. Discs are a pure marketing exercise as the manufacturers are running out of ways to go to upgrade road bikes. If you have a top spec road bike from the last 5-6 years, you're not going to be faster on anything newer.
The tighter pad clearance on road discs is the main issue I've had to deal with. SRAM Rival were very problematic but Shimano GRX seem better quality and much more reliable. They're still sensitive to setup compared to my past MTBs though. Good to hear they're going to be working on it.
Exactly... I don't understand why both Shimano and SRAM are having such a small clearance and are using such a crap brakes. They have technology to avoid all of these issues. I have cheap Shimano Deore disk breaks on my cheap MTB and they never ever rubbed, I never changed oil in them and I bleed them like once and they are working flawlessly after 7 years and close to 10K of riding in all weather. Only maintenance is that I am changing pads once or twice a year (they cost like 5 bucks) and I did changed rotors this year after 7 years and I was not even out of tolerance yet I just did it as they have sales on the rotors. I would love to just take those and put them on my road bike instead of my expensive Ultegra ones. I don't grasp how is this even possible.
You're assuming a linear lever throw/caliper piston relationship, but shimano has always used rising rates (servo-wave). They'll probably use this to get around the problem.
hopefully not. you have to move the lever 75% before you get any sort of bite with shimano xt's. before that its like they're trying to stop a train by running their fingers along the side. servo wave needs adjustability. it hasnt got it.
You’d probably want something like an S-curve in your rates: a low advantage rate to take up piston slack, and a higher but steady rate to clamp the rotor.
A couple things. Shimano uses servo wave (variable leverage), so there is "free lunch" to some extent -- it can probably be tweaked for more pad clearance, but at the expense of backwards compatibility. Also, Tektro does offer their Dorado system with thicker 2.3mm rotors (though not with road levers).
Servo wave is a nice idea, variable lever ratio, but it just doesn't seem to work very well if at all in my experience on road. MTB xt brakes, never had an issue.
@@PeakTorque Have you tried the GRX-shifters and calipers? These are the only ones that have servo-wave (on road bikes). Not perfect but close in my experience (still squeal like a pig when it's wet)
All servo wave does is alter the lever feel to take power off the caliper so that the initial bite isn't as harsh. And it wears out and rattles horribly
I mean, if heating is the issue there are so many possible solutions. Not only can water be misted into the rotor, you can use big mountain bike rotors, you can make a thick vented rotor with air cooled vanes between the rotors, like on a car, use a rotor on each side of the front wheel, etc. But honestly, don't lose sight of the big picture. Racing motorcycle brakes work really well and they are pretty simple. If something about a bike disk brake isn't adequate, just start referencing motorcycle designs. The most obvious difference is just rotor diameter but a large mountain rotor seems like it's proportionally comparable to a motorcycle brake so I'm guessing something is getting overlooked in terms of design or materials.
@@fieldlab4 motor cycles use cast disc rotors that are pretty heavy I. E. Have high heat capacity. Bicycle disc brakes use stamped stainless steel rotors that result in inherent internal material stresses. The construction, engineering design and quality of the humble motor cycle brake is an order of magnitudes higher than what the bicycle industry attaches to your bike
I'm genuinely really happy with my road disc brakes in the UK, they feel miles better than rim brakes. But yea I don't have a giant mountain to get down. Although I have ridden at 70kph+ I've never had to stop really hard from that speed (say for a hairpin turn). So I can see that it might be a problem for Froome
Great post. For 90% of Riders discs are absolutely the best option. The rest are real Pro's and pretend Pro's who can simply use rim brakes. Unfortunately, it seems to the cool thing to trash disc brakes, so all the Sheep are onboard and they just won't stop whining.
@@SaintKimbo Agreed. They can simply use rim brakes and even be very glad that others use "worse tech" disc brakes because they'd win more races. But for some reason, they are mad about all this.
Absolutely agree, I have bikes with rim and disc brakes and disk brakes I find so much better on British roads with often steep short drops with blind off camber bends. If only they didnt honk under load so much
@@StopTheRot Thanks for the laugh, Bozo. Maybe I ought to change the discs out for rims on my Ducati, jeez they might "depressurize" and start rubbing and stop working ! If they "COULD NOT get their disc brakes to run smoothly" I think that they probably should go to Flinstone style brakes, 'cause if they are that mechanically ignorant, even rims would be a major mystery to them and they'd probably fuck them up too ! Be honest and admit that you are only against disc brakes because your Pro heroes don't like them and you are like a scared little boy, too afraid to be seen to be different from the rest of the drooling sheep.
@@maxgrass8134 more pistons, more oil and surface area for the heat to escape plus the larger contact patch and brake pad I think you'll find they do help.
I've had disc and rim on a tcr like you and prefer the rim bike. I had issues with the discs rubbing and a leak from the master cylinder which almost wrote off my sportive the shifter was replaced under warranty but wasn't fun loosing my front brake on a descent. Huge respect to froome as I totally agree using both on the same bike. Personally I'll stick on rim as long as I can. Alloy wheels in winter and carbon wheels in summer been perfect so far.
Go for it. People can keep using rim brakes and inner tubes and horse drawn buggies as much as they like. Knock your socks off - in the meantime, I’m enjoying brakes and tyres that work much much better.
@@froggy0162 I don't use inner tubes I'm using a tubeless set up reguardless of it being disc or rim. Assuming rim brake users only use inner tubes is just stupid... Also a 28mm gp5000 tyre for example will work idental reguardless of the brake type 😂 I can lock up my wheels on either bike so why I need better brakes is questionable imo... The issue is traction which is the tyre not the brake.
I'm old enough to remember racing with Wienmann brake levers that had two lever positions, which was very useful if, for instance, a slightly untrue rim caused rubbing during a race. I wonder whether a two position dis brake lever, allowing a rider to temporarily increase the gap between pad and disc without stopping, might be a marginal gain worth having.
In my opinion and what I see is, disc brake bikes are just more practical especially on long endurance rides or city riding/bike to work. Rim brakes are just easier to maintain, easier to fix, just easier to work on. Both can be used for racing, obviously, but rim brakes has and will always be reliable, a tad bit lighter, and it just works. I honestly got no reason to upgrade my rim brake bike other than the thought of having to replace my wheels every two - three years.
At the risk of sounding like a "save the rim brake" dork, (and being closer to a dentist than an engineer...) I think the real missed opportunity was Direct Mount rim callipers. Such a good, solid braking force and light! Not disc brake power but more effective than standard single bolt rim brakes... but the industry moved towards discs the at the same moment DM brakes became a viable option.
I had integrated rim brakes on a 2015 BMC Time Machine TMR01 with a set of 2020 Mavic Comete Pro SL wheels + yellow swissstop pads. I remember I was with a friend this last summer and got stuck in a downpour, and I'd be hitting the brakes half way from one stop light to the next One second has passed: NOTHING Three seconds has passed: NOTHING Five seconds has passed: Starting to bite Seven seconds has passed: We are somewhat slowing down Ten seconds has passed: we're almost stopped Legit useless in the wet. If you use alloy rims it's nowhere near as bad as carbon, but it is still very scary. If you ever plan on going with carbon rims imo go disc, that way your rims also aren't wear items.
@@sabamacx So you're served as a consumer. You have nothing to complain about. You're probably a braver cyclist than me, riding in all conditions too! The industry refuses to let the rest of us continue to have what we want.
There is free lunch! Shimano calls it "servo wave" and I think other companies use the same system. Basically it realizes different leverage ratios during the free stroke and on the contact point. In the MTB world it has been around for years. Some people don't like it because the brakes have "less modulation".
I find disk brakes to be very reliable (rubbing is easily fixed, I'm not sure how/why they'd warp) but I think for MTB the #1 requirement is smooth, textural brake feedback to deal with adverse traction. It's honestly the hydraulics that have changed it.
If you have heat issues with disc brakes, won't you have heat issues with rim brakes? Especially with carbon wheels? Yes, mountain bikes may go slower when using brakes, but they get used much more often.
I think the issue Froome is remarking on is that you can have piston retraction/travel issues and warped rotors. In a comparable scenario rim brake calipers won't cease to retract or apply themselves evenly and rim brake tracks won't deform to where you end up having rubbing on the brake pads. Even in the case of some issue with rubbing, rim brake calipers can quickly be adjusted while riding to resolve the issue. Granted, I'm not remarking on the issue of brake track wear, brake pad wear, or issues with heat on the tires/tubes because Froome likely has little concern for those things as he gets a fresh set of pads and wheels whenever he needs them. I'm also not a rim brake evangelist either, I prefer discs; however, I am a MUCH different use case than a professional (12 hours a week vs 24 hours or more for a professional), and my equipment will wear very differently.
@@DanKolan I am not arguing with that point. That is one frustration with disc brakes. If there is an issue, you cannot simply reach down and open the brakes a little. It doesn't happen every ride, but on the occasion it does, it is annoying. Honestly, if I was a tour contender, I'd probably opt for rim brakes. My comment was aimed at Peak Torque and his comments.
@@LordAus123 heat absolutely is an issue with rim brakes too. Especially with carbon wheels. Sustained braking with carbon wheels can cause the brake track to fail and delaminate.
@@DanKolan Regarding rim brake pad wear, I have heard of cases where rim brake pads heated up so much that a single alpine descent wore through the pads. That just doesn't happen with disc brakes, unless your brakes are contaminated with sand or some other abrasive.
Disc brakes might be a problem for road racing, but it really is one of aerodynamics, isn't it? Also, do road pros really go to the point of overheating when braking? It's not like they descend constantly braking, and you very much have ways to increase your system boiling point through the use of bionol and metallic pads for instance if need be. The constant rubbing is an other issue altogether, but it takes 2min to fix. I genuinely think there's no point in going for rim brakes aside from aesthetic reasons if one isn't a pro racer. The sheer advantage in braking power discs offer is just too good a feat, especially if you consider all-weather applications. It's also almost completely set and forget if one goes the hydraulic way with a mineral oil system; one change of pads once in a while and that's it, there shouldn't be any need for bleeding for years to come if it's been well set up.
Honestly, coming from MTBs, no, it doesn't always take 2 minutes to fix. There's a plethora of reasons why the disc is rubbing. Is the caliper centered, is the disc straight or bent (it does that by itself through time), are all the pistons moving or are some of them dirty? How is the pad spacing spring handling pad wear (some are too stiff at the top, causing the pads to not come together at the top and causing uneven wear, etc.), what is the pad spacing actually (it can change on the same system from time to time), etc.
@@Primoz.r I agree with you partly, but most of the time, if your caliper is centred, the rubbing will be due to a bent disc, which is quite a quick fix. Never had a problem with pads spring though, I suppose I'll see as time goes by. Regarding the changes in pad spacing, how could that arise exactly?
@Pablo Morales Sure, but you've got systems to assist with that like Ice Tech and Freeza. Also, you should simply never arrive to the point your disc overheat in the first place; if you follow the best practice of braking in small amounts periodically instead of smashing on the brakes uninterrupted, the brakes have plenty of time to cool off in between each action.
@Pablo Morales But high-end rotors aren't just pieces of steel though. They've got radiators, vents, etc. to dissipate heat and cool faster. Warping will occur with any rotor to some degree, but if Froome, or any roadie for that matter, manages to overheat theirs, I'd say that they don't really know how to brake with discs yeah.
A rim brake job requires a alan key. A disc brake job requires a expensive bleed kit, fluid, pads, rotor alignment tool, youtube, google, and a wasted weekend.
The clearance between disc rotors and pads is governed by the retraction of the piston which is controlled by the piston seal and the design/shape of the groove in the caliper that the seal fits into
@@hippoace If the oval ring is symmetrical, the chain length needed to wrap around it won't change at all while pedalling as the chain will be wrapped around the half of the chainring in front of the BB axle at all times, which will always contain half the teeth of the chainring. If the top and bottom runs of chain are significantly off parallel there will be a slight effect, but not a lot.
I think Disc's are good for wider tire set ups say 30mm or wider. I like 25mm on the front and 28mm on the back. I also live in Holland so rim brakes make perfect sense to me. Great video PT I'd like to more on this topic.
Except the constant rain and damp ground in Holland makes rim brakes a nightmare, to the extent that I gave up my carbon rim brake bike and moved laterally to an aluminum hydraulic disc brake bike, both R7000 105s. Even with direct-mount calipers, it's hard to stop after a rainy afternoon on the Dune of the Hague. I can't even remember when is the last time I come home with wheels not coated with brake dust on the rim bike.
Discs vs rim is like when 911s went water cooled. Better in every way but people lost their shit. Even if you only think discs are equal in terms of performance (not true they are only close to equal in the dry) the fact the wheel is no longer a consumable makes discs a no brainier. Wheels on my bike have a lifetime warranty, hard to do that if I’m wearing it away every time I brake.
It's all to do with the weight(mass) you are trying to stop..... Mtbs weigh considerably more than road bikes..... Especially the ones weight weiners ride...
@@markstorer7204 Compared to the weight of the rider the weight of the bike barely counts in either case though. Most road rides are long periods of not braking at all with short periods moderate braking and very few extreme braking events. A MTB trail is often nothing but extreme braking events one after another with gravity assisted acceleration in between, combined with a healthy dose of contamination from mud and dust, so the brakes on a MTB take a lot more abuse.
Froomey also mentioned a lack of stiffness in his integrated bars. Do you think maybe that might come from the lack of supporting material at the t joint of the bars? I would guess it's hollow there, contrary to a separate bar and stem which has extra material to support the clamping forces
That is probably just an issue of the model, not integrated bars in general. I have used the Syncros RR1.0, which is amazing in all aspects, but also had some mileage with the Canyon H36 which is so elastic, its probably better suited for dogs to play with.
Ok just face it, disc are heavier but more effective in rain, rims lighter and competitive in dry condition. What really matters is tyre grip. If you could lock up ur wheel with a same pulling...then not much differences.
Wish I'd recorded a conversation similar to this I had with a hydraulic brake engineer many years ago when bicycle disc brakes were still mostly a dream. This guy (from Magura perhaps?) claimed a hydraulic disc caliper and rotor system that would actually deal with the heat developed by roadracing bicycles would require far too much mass (as in WEIGHT) to be marketable, while anything less would simply be dangerously inefficient. But here we are, wonder where that guy is today?
Always interesting to watch and listen to your videos. For my most recent bike I was talked into going disc rather than rim brake, primarily on the benifit of better braking. Being old and slowish - 35ish klm/hr is a good speed for me on the flat - my seat of the pants experience has been just that. My speeds and my rides may well be more directly comparable to a mountain bike in terms of forces and heat disappation. Again, thanks for the thought provoking videos.
Servo wave, man. There's no downside to less mechanical advantage in the travel range before the pads contact the rotor. I assume Shimano will add a little cam as they do with the mountain bike levers to have adjustable leverage. That aside, the solve for road disc in general is just bigger, thicker rotors. They started at 140mm (hilarious) and now, five years on, 160mm is the standard. It'll be 180mm or more soon. The cooling rate for the calipers (and the little pad fins) just isn't high enough for that mass to make an appreciable difference (especially when it's trendy to hide them behind fairings).
Love my disc brakes - don't seem to have all these issues. I maintenance myself and follow manufactures guidelines. Its not always the brake thats the issue
@@markwells8798 why are you such an angry man..........instantly move to personal insults for no reason. You may need to see someone about your anger issues
Disc brake development will continue off the charts. So much so all the current disc frames will be obsolete cause they will need different mounting spacing. So you need to buy newer frames for better disc brakes. We are just chasing own tails.
@@thomasjousse2427 you are assuming current flat mount system is the end game. They could easily change the spacing or come up with clever ways to integrate caliber cavity into the frame, therefore making current frames obsolete. Goal is to make people buy new bikes. I see a new Rose bike already has the bolts inside the frame out of air turbulence.
Cool video! I’d add two arguments for discs on road bikes: better cooling because higher speeds mean more air passes over calipers/rotors Less braking on the road then MTB. Even on long alpine descent you hit the brakes and then let them cool. MTB descending there is almost no time you are completely off the brakes.
Carbon-carbon brakes seem to function quite well in F1 at high temperatures. Just putting that out there. I, for one, welcome our new carbon overlords.
Eh, I don;t really have issues with either but I flex rim brake bikes enough that I do get wheel rub on the brakes pads if I'm out of the saddle sprinting or climbing. People worry too much about this shit. Rim brakes are fine, disc brakes are fine.
About pad clearance vs force multiplication: the "Servo-Wave" mechanism was created for this exact reason which effectively introduces a lever ratio increase as a function of lever throw. As far as I'm aware it's also being used in road levers. In assuming that Shimano will compensate for the detrimental effects at least partially by increasing the "servo-wave" effect (steeper curve/more ratio change).
I always wondered why it has worked for MTBs for years but there are so many complaints with road bikes. Frankly, I think for the average rider like me the disc brakes don't have an issue. I've never had them rub past initial setup and they stop me better than my rim brakes. But I am not pushing my riding to the extent of a pro racer so I'm never going to see those issues they complain about. And frankly, I feel that most everyday riders out there complain about it because that's what the pros complain about. Just the same with weight. Great explanation. Thanks.
Road calipers are pretty crap but what would stop you from mounting a MTB caliper on your road bike? As long as you use a post mount to flat mount adapter you could probably reduce the problem.
In the early days of road disc, the two disciplines shared the Post Mount standard. But then I suppose Shimano decided that this was too user friendly having cross compatibility between road, CX and MTB...
@@jackhammer40k_ Shimano have released a flat-mount XTR caliper. Surely that isn’t less powerful than the post-mount version. So don’t think it’s just as simple as saying ‘mtb calipers are more powerful’.
@@mf0u3021 I wasn't making that claim. I'm more decrying bike part manufacturers making "innovations" in the name of progress when it's quite transparently in their best interests and not in those of the customers'.
@@mf0u3021 Didn't know Shimano made a flat mount MTB caliper that's why I mentioned the adapter. The reason I figured MTB calipers might improve braking performance is that they have more thermal mass, not because I thought the style of mount would influence performance.
Nice logical explanation. In my experience MTB does often achieve higher speeds than you say, but the thermal issue does not seem to arise because MTBs seem to have more appropriate disc braking system - even the weight sensitive XC gear. I think in time the specs will improve to provide better/more appropriate disc brakes on roadies.
I have riding shimano ultegra disk brakes on my road bike for 2 years. I am a 90 kg rider. I have never experienced “constant rubbing” or uneven caliber retraction issues. The hills near me are only small with relatively short descents of less than 10km and I get frightened when riding faster than 70kmh on public roads. I have never had an overheating or stopping issue. I recognise that it could be a problem with real mountains and have watched a car go over the edge with brake failure in the Australian Alps when they used their brakes for a 40km descent rather than engine braking. I love the better rim design on my deep rim wheels because there is no need for a brake track and I also love being able to stop in the rain.
I am going to go against the flow here. I don’t see why people have issues with disc brakes. I have 3 bikes with discs. 2x Dura Ace and 1 Ultegra. Of the 3 1 made a noise 2 didn’t. I centralised the callipers, and swapped the wheels between 2 bikes neither bike made a noise, I then swapped them back and the noise has gone. There are less moving parts on disc brakes and less service requirements. I prefer discs to rim brakes and will never go back.
Changing discs and pads is more service requirements than replacing brake pads, which is more wearable parts, which is more money, which is why they're selling them as standard now.
This is against the flow. You are on a train going the wrong way. Bike industry was so much in a hurry and so greedy that have not taken in to consideration safety before releasing weight winnie disk brake designs. It would be better to give the choice of rim or disk in the future, at least till they come out with an all around sound system.
@@fergusdenoon1255 The fussiness of disc brakes is greatly exaggerated by people with little experience. Maintenance is different, but not difficult. You almost never have to change rotors. I literally have 10s of thousands of kilometers on my rotors. On my mountain bike they are getting a bit thin, but that's ok, it is 8.5 years old and the bike will be replaced soon. I never had to change them on earlier bikes, too, they all were lifetime-of-the-bike parts. Even for people who ride more than me, I don't think you have to change rotors often … unless there was an accident or they were contaminated. Yes, brake pads need to be changed, but that isn't more of a chore than changing rim brake pads and centering them; you can skip the last step with hydraulic (disc and rim) brakes, because they are selfadjusting, a huge bonus. The only thing that is easier with rim brakes is to judge the wear of your pads - you can do that on the bike with rim brakes. Disc brake pads aren't more expensive than rim brake pads. I reckon disc brake pads are cheaper than rim brake pads for carbon rims, though.
@@maxlein1246 I have both, I've had to change 2 rotors, both buckled from being hit by branches, meaning a long walk home. There's pros and cons to both, there's much more con with disc brakes including them being attached to the weakest parts of the frame, rear stays receiving downfirce in a construction designed to take up force. I also prefer the more refined braking that comes from rim brakes. I designed and made a road bike that has rim brakes integrated in the frame and forks so it doesn't even look like there are brakes on my bike, can't obtain such lines with disc brakes.
I get it, but the (non existent) wet braking on my carbon rims is downright dangerous. Plus theres the wear on those very expensive rims. Reluctantly, Im going to discs next purchase.
Would be interesting to run the numbers on the aerodynamic drag induced energy losses, ie how much of that 70kph equivalent energy actually needs to be scrubbed by the discs and also how much the extra cooling of the 2x wind speed over the calipers / disc gives you.
4 pot calipers usually mean bigger pads. Bigger pads mean better heat absorption, but more surface area decreases clamping force, so you end up needing more leverage (longer stroke at master cylinder) to equal the same pressure as a smaller pad. Heat's a big deal though.
Anyone complaining about the weight of current road bikes wasn't around before carbon fibre took over from aluminium, titanium and steel. If we're going to argue against disc brakes based solely on weight we could equally argue against sti levers, electronic shifting, deep dished wheels etc.
1) I feel for RoJ the moment he will watch this video. 2) Non te la cavi male in italiano. Ti do 6. 3) Wouldn't you agree that you are downplaying (a tiny bit) mass? Between a bike and a Vespa there is still a significant difference. Assuming a 10kg bike, an 80kg rider and a 100kg scooter, the energy required to stop the scooter will still be double at any given speed. If anything, the main take-away for me here would be that the bike weight per se has only minor consequences To me, that matters for bike touring for instance, in the sense that if a given brake system will perform well when the bike is unloaded, it will perform almost equally well even when that same bike is full of panniers. Finally, if you ask me the one "crime against humanity" bike manufacturers committed was to go for this damn flat mount standard and its limitation to 160mm. I would spec 200f/180r on all my bikes, tomorrow, if I could.
The speed argument is nonsense, the average(!) speed in Maribor in the world cup (downhill) was over 50 kph across the whole track 10 years ago. 29ers should increase that, but sadly it was kinda wet the last two times the world cup has gone there. And the speeds are not that high just there. Plus not everybody goes 60 kph on a road bike. Then there's the gradient, which is usually much more severe for mountain bikes, meaning you brake longer or for a higher percentage of time. Sometimes it's hard to even let up to get some air in between the pads and the disc. Granted, 4-piston calipers have become the norm in anything that's not XC, 200 mm rotors are pretty standard on anything with 140 mm or more travel, but still. I'm not a roadie and don't have experience with any road brakes, but in MTB the lever throw, braking power and pad clearance has been successfully dealt with with progressive mechanisms in the levers. Unless you have a Guide/Code R which doesn't have a swing link and you're just moaning around the internet how horrible the brakes are without knowing why and throwing all Sram brakes into the same bin. Rubbing is an issue everywhere and I fear is caused by dirty pistons getting stuck. Bellows covering it might help with the actual sliding interface not getting dirty (or being kept lubricated with grease maybe even?). As for surface area and cooling... Start looking into Al discs? Make them 3, 4, 5 mm thick, that way they won't bend, won't rub as much and you'll have some more heat mass (Al has ~double the heat capacity per mass). It can't be impossible as the 1st gen Lotus Elise used aluminium brakes (for lightness), so how hard could it be? Also, what about ducts? Channeling air actively towards the calipers and rotors? Yeah, it will kill aero, I know... Maybe add a system on the brake line to only open the channel when you are braking? EDIT: watched his video, he mentions that the thing works on the stand, but not on the road (rubbing & co.). Is the bike flexing under his weight? Are the wheels inserted properly? I ALWAYS tighten my wheels with the bike on the ground, so the hubs sit on the dropout ledges, in the same place every time. Even with through axles you can put your wheel in crooked. And it can cause rubbing (and shifting issues as well).
It is so much easier to go 60 on a roadbike than it is to go 50 downhill. Pointing your bike down a hill and getting on the brakes to save your bad technique is the whole problem.
I think the point about speed made in the video is valid though. The 50km/h average on a World Cup DH track you're talking about is done by pros and the finishing times are like 3 minutes. An average road rider could easily find themselves at 60km/h plus just rolling down a reasonably tall/steep hill, also there may be some conditions on the road where you will need to be on the brakes constantly (twisty roads, poor visibility around corners, stuck behind traffic etc).
All I am seeing/hearing are an anecdotes. Sure there was some good science here but it never looked at the system as a whole. It was simply an academic exercise. Nothing wrong with that as it provides a base for imperial science to be done but until then it's merely conjecture. Someone needs to lab test the two systems side by side so we can actually see the real differences. Two pro level race wheels, one disc one rim. Get them up to a set speed and slow them to a set speed repeatedly to simulate a mountain decent. Then test a side by side long break drag down the same decent. Then show the results of both breaking systems - play, wear, rub etc... Until then I'd have to error the side of shimano (sram etc) engineers and my own anecdotes.
i've had an overheating front brake on a very steep descent. on hard breaking the resin pads went to 0 breaking performance instantly @ aroud 60 km/h I used to be a fan of discs but this broke my trust. System weight 105 kg Brakes: GRX 810 Stock with upgraded 180 mm Rotor
@@404nobrakes you are right, rim brakes on carbon wheels don't brake well the first 10 metres in wet conditions. But was there a real need to stop offering rim brakes bikes???
@@kikal85 It's really expensive to offer 2 identical bikes, one with discs and one with rims. It's far more profitable to convince everyone that they need discs. Don't be surprised if new top end groupsets become disc and electronic only. It saves a lot of development cost. 1 groupset instead of 4.
Regarding Caliper vs Lever throw ratios: can you address that by making the actuation non-linear? You can have the first 10% of the Lever movement be responsible for the first 90% of the caliper movement and then you have a full 90% of your lever movement left to use on your actual braking
That's all well and good but still disc brakes are forced down consumers (and the peletons) throats for nefarious reasons. Manufacturers could just offer both options and let the consumer decide. There are some shady business practices going on here.
I suspect all those who love rim brakes much have never worn through brake track on their wheels with the abrasive paste that comes from winter commuting on gritted roads. I think the power that disc brakes have is actually way more than is needed at the moment (obviously grip strength dependent) so I think a less powerful brake with more pad movement would be great.
I think on fully mechanical brakes like trp spyre. It would be easy to make the pads move initially faster and then the speed changes to more power when pads get closer to disc. When I took my trp brakes apart for cleaning and re lubricating, there were 3 pall bearings inside on ramps in slots. when the ramps move, the palls push the ramps away from each one. If the ramps had a curve.. at first deep ramp and then goes more shallow. It would solve the problem with too little clearance. Braking power would be same, free play of lever would be same, but the clearance would be bigger.
Mechanical discs like an Avid BB7 really do solve this problem allowing the user to adjust the piston throw themselves allowing you to balance the lever feel with risk of brake rub. Mechanical advantage remains the same no matter the adjustment. I assume hydraulics win in mechanic advantage which is why they have better stopping power?
I have BB7 on a commuter bike I built to look old school with barcon shifters, polished alloy, etc., but stop when I get a red light barrelling downhill in the endless Seattle rain. I have Shimano hydraulic on another bike. The Shimano hydraulics are MUCH nicer! They are self adjusting with wear, center themselves better, and break better.
I live in Japan and ride mainly in the mountains here. Since there aren't many particularly nice aluminum wheelset anymore I like the trade off of disks with carbon rims for long descents since I don't get wheels for free. Have had very few issues with rubbing, but many riding buddies do. Maybe I just got lucky!
Maybe the bike industry could learn something from the car industry. The faster your car, the bigger the discs. One reason that car wheels on sports cars are getting bigger is to accommodate bigger brake disks. That is also the reason that tires are getting lower in relation to their width, so that the internal diameter of the tire/wheel combination grows even further. To make the brakes stronger they went from 2 pot (pistons) to 4 pot to even 6 pot on bigger/faster cars. To counter the heat problem the discs are ventilated, meaning that they are double with ventilation channels in between the layers.
The free snack comes from servowave. Non linear pad travel vs lever travel. This way you can have the extra clearance and very low braking force in the "empty space" until the pad contacts the rotor.
My guess is Shimano's probably going to use a goofy lever design that has more piston travel at the start, and then more mechanical advantage at the end. It'll give people "powerful" braking without rub, but it's also probably going to be very sensitive to pad wear, and tougher to modulate. I'm not competing with my bike, so my standards are probably a little different, but I put some biger rotors 180F/160R, on a set of TRP Spyre cable calipers, and I think they're pretty ideal for a non weight-weenie road bike. They're actively pulled away from the rotor by the spring, which fixes some of the causes of rubbing and, the slightly larger rotors make up for the reduced mechanical advantage. The only downside is that you do need to give the pad adjusters a quarter turn with a 3mm allen wrench every few weeks when the lever travel starts to get excessive. My mountain bike, and cargo E-bike have hydraulics, and big 203mm rotors, and while they stop very well, I do get tired of them rubbing, and replacing pads that are unevenly worn because one piston retracts better than the other, etc. That said. I'd still rather take all the downsides of them over a rim brake that's going to chew up my rims and triple my stopping distance any time there's a little rain (I live in a very rainy city).
The issue with fitting larger rotors is that they further compromise aero and increase the already impressive ability to catch crosswinds. I regularly ride in crosswinds and swap between a disc setup consisting of a 160mm front rotor and 45mm deep rims and rim brake set ups consisting of 50mm deep rims. It is surprising how much more the disc setup suffers in the crosswinds. It seems in the quest to fit disc brakes more problems and compromises are made than solved. If a problem existed in the first place?
Okay, so car and motorcycle discs rely on the square section seal on the piston being deformed and returning to shape to retract the pads. The section of a seal on any pushbike is not sufficient, hence the extra spring which you never see on an automotive application. If you want to see a solution to braking force and heat dissipation, check out a Buell motorcycle. They use a 'perimeter' disc and can get away with a smaller calliper, also single sided.
I want to my experience (or should I say, anecdotal evidence) to the discussion. I went on a bike tour to the Alps. I have descended Stelvio and Mortirolo on 2015 MTB disc brakes, and the brakes didn't fade and I'm here to tell the tale. I had heard of tire blowouts in rim brakes but I think it is largely inexistent with modern alloy wheels, because one of the riding buddies was terrified of descents and dragged his rim brakes on these 15-20 km descents, with panniers on, and no blow outs happened. I would suppose modern road disc or rim brakes don't fade or blow out as often as it seems to be implied in the discussions.
I really love this channel. I love people who tell the truth- who give it to me straight like a cider made from 100% pears. I love people who are leftfield, unorthodox- those are on the fringes. These people include this channel, Hambini, Lance Armstrong, Stuart Lee, Frank Skinner and Stephen Fry. :)
Pinned reply to many comments: I do not state in any part of this video that rim brakes are superior. Im saying road discs don't seem to be suitably sized for the thermal load. But hell they still work better than rim in the pissing rain on a 10km downhill. If i had a component company, i wouldn't have released disc road brakes in this state of development. They're not good enough. Too many inconsistencies, noise, too little cooling.
The question now is. How many of us normally ride in the rain and worse yet, downhill? I never do. And neither do most people out there. Meanwhile, for that hypothetical one-off you have to put up with all these disadvantages 99.99% of the time. But hey! Let people ride whatever they want.
You are just not stating the obvious :D
@@joseluisrodriguezvazquez6082 Completely agree, I do regularly descend at speeds of 50mph to 60mph and in the dry rim is King in the wet I don't care as I have no intention of relying on such optimal braking performance as my tyres will let me down before rim or disc brakes will. I swap between rim and disc, I really like both but as a complete package/race bike rim edges it imo.
so, you have come up with the solution > water cooled discs
... race you to the patent office !!!
Time to make your own rotors
I don't have these problems with the discs on my bike but that is probably because I'm 4 times slower then Chris Froome.
Also, probably the reason why Chris says those problems is that I heard he trains for the climbs on relatively flat roads by slightly breaking while riding
@@Cv-uh9bt in that case the disc rubbing is a feature!
That'll be it exactly.
Same here!! 🤣
Weight weentard here. I remain unapologetic for demanding lightweight shit, haha. I think the variance of system weight is also hilarious. I weigh 51kg with a 7kg disc brake bike. System weight of 58kg. There are 107kg guys out there riding 9kg bikes; 116kg system weight. Most of the time they're equipped with the same braking systems as me. That would be like a pickup truck having the same brakes as a Mini, it just ain't gonna work. The industry has convinced you that you really do need 3 different depth of wheel to suit every occasion; but a 50kg and a 100kg guy can use the same brake levers and calipers no problemo.
Great point being made here.
So what I am hearing is 140mm rotors
Amen.
It’s more like a mini having pickup truck brakes. The brakes would be designed for the larger weight not the smaller one.
How tall are you!?
There is a solution to this... Make the discs 622mm in diameter.
Im sorry, what a cracking name you have.
or 584 for some gravels
And have it be multiple kilos heavy and hit things with it all the time yay
@@kaedeschulz5422 You may have missed something.
@@PeakTorque don’t be sorry, just keep repeating it over and over in your head.
Well said. To be fair, It's not just the weenie demand in itself, it's also the brands bombarding everyone with 'Lighter And Stiffer!' each year, for the last 20 years.
I don't want lighter and stiffer, I just want stiffer. I can remove 5lb off myself for free. Also if I, or other people cared about weight this much then deep section wheels wouldn't exist
@@YuriThorpe deeper rims directly correlate with aero advantages that outweigh weight disadvantages on most roads. Heavier, larger discs and calipers only correlate with better braking at the expense of both weight and aero.
@@YuriThorpe Just ride a bike with round spokes. That will increase the bike stiffness as well.
@@SurpriseMeJT the stiffness in wheels comes from the tension and the bracing angle of the spoke not the shape of the spoke (i assume of course you're referring to bladed vs traditional plain gauge or butted spokes.)
@@jonnythelegs2597 The number of spokes matters too. I'd love to see the science on the lateral rigidity of bladed vs round. I've built the majority of my own wheels for 20 years and I don't quite buy the simplistic notion that spoke shape has zero influence on lateral wheel stiffness.
That scooter analogy is a damn good wakeup call.
Total system weight of road bike + rider is in the range of 50-100 kg. Total system weight of scooter is around 150-300 kg. Rotors on even a little 150 cc scooter have significantly more thermal mass than on your weight weenie bike, even though they max out at about 75kph. We're putting big demands on our lightweight road bikes that's for sure
I'm not concerned by brake setup weight but I want a system that works without rub, noise, etc. The industry is forcing my next road bike option to only be a disc before they've solved these problems. I have discs on my MTB and gravel bike but don't need them on my road bike.
Exactly, the freaking rubbing and weird noises can be a nightmare, in my Mtb every time the pads are a little over 50% worn the rubbing nightmare starts and it's something I really don't want in my roadbike. The positive side though is better breaking when the pavement is wet so I don't know, eventually I guess I will end up with discs, besides last week I was looking at new bikes and like 70% of the new models use discs now.
It’s really because people want carbon rims, the only solution to personal injury lawsuits was to resort to a belt and suspenders solution, instead of staying or going back to alloy. That’s all they can do. The problems with disc brakes even my Shimano ones, who knows when they will be eliminated. Autos had same issues probably for several decades before finally getting rid of them, namely squealing. I’ll never ever ride carbon rims for safety concerns.
I live in the alps and am regularly doing descents of between 500 metres and 1000 metres on road and mountain bike. The road descents are completed a lot quicker and the braking requires much greater deceleration. Typically 70kph to 30kph for a hairpin in just 20 metres. The heat stress on the brakes is enormous.
I bought a new bike with disc brakes and whilst there have been some clear advantages, sometimes the brake behaviour is appalling with a lot of noise and vibration caused by the heat.
And the cost in replacement brake pads and discs is quite large compared with rim brakes.
Interesting. Can you comment about wheel wear with rum brakes? Do you have experience with this?
I would have thought that the cost of pads is tiny compared to the cost of the bike....
Maybe don’t try to stop within 20 metres to reduce the stress? I gather you didn’t brake as late when in rim brakes, and it never bothered you. Discs aren’t an invitation to brake as late as possible in my opinion...
@@patrickparisienne1917 it is clearly one of the advantages, and one of the reasons to take disc brakes for racing. Although, it is hard to say if there was an advantage of discs in big races in last years.
Maybe try a parachute? TBH, I have carbon rim brakes and there's no way I would take it through a hilly section without having deep experience on that section beforehand. Given my motorcycling experience, I'd much rather be on discs in the hills.
@@in4merATP I agree discs are more efficient than rim, but unless you are racing, there is no need to push the brakes to their limits all the time. If you stress any mechanical components there cannot be complaint when there are problems.
Bike manufacturers should turn to Motorsport brake specialists like a Rambo, Alcon and AP who have the experience, detailed knowledge, and the budget to have sorted these problems before.
The problem is no one will want to pay for ceramic based discs, and the fact that they will be thicker, needing different calipers...
Froomey sending ripples across YT. Awesome summary mate! Thanks.
Froome speaking on anything cycling is like Einstein speaking on physics if he was alive.
Was cycling the other day on my mate's bike, borrowed his tarmac with dura ace callipers on dura ace aluminium braking surface wheels. Car pulled out in front of me, pulled the brakes, nothing happened. If the car didn't stop I would have been through his door window. Disc brakes at least work.
Thats the other issue. getting rim brake sto actually work means eithe rrubbing OR supe rsoft rubbe rthats no good for extended use. I used to run brakes on my BMX bikes which were all rim brakes and getting them so you could do stoppies or rear taps was a nightmare. Braking power of rim brake sis ajoke and onc eyou pick up speed in some case you can't actually stop or even slow down, at best you can stop acquiring speed!
Ineos seem to be ok, last of the rim brake pro teams going down mountains, also every road cyclist pre 2010 managed to stop? Maybe you don’t know the bike / it wasn’t setup correctly / you need to start on hand grippers to increase your grip strength?
@@MrHcharles I agree I'm not used to rim brakes anymore but I did used to ride them, i remember when a van pulled out on me once and i pulled the levers too hard and double skidded, almost hitting the side. Pros are lucky because when they race they have both lanes and knowledge that no car will be there :/ I hope i set thr brakes up right, I've been a mechanic for a few years 😅
I started cycling on mountain bikes, back in the cantilever and v-brake days. I understand roadies like rim brakes for several reasons and that today’s systems are much better than the crappy ones I had on my bike 20 years ago...but I still like disc brakes on my road bike...
Same.... I missed the start of disk brakes on MTB's in the early 90's and put up with crappy V brakes for many years. When I bought a new roadie in 2015, I was happy to wait a couple of months to get a disk brake roadie. I am a bit of a zealot about them though...
@@richardhaselwood9478 If you think v-brakes are crappy you definitely need to try some cantilevers. For a while after disks were available, professional DH racers were still running XTR v-brakes on the front of their bikes, quite simply because they were still more powerful than any other option.
@@peglor I am old enough to remember what passed for "Downhill bikes" back in the 90's. Memories of reading an MTB mag (Australian) about some racers who raced XC and DH on the same bike. These bikes had V brakes of course :)
They deserve to be recalled once they sort these issues out, especially considering they don’t meet market demands, except in weight which IS an infection, well put. We(the Industry/Buyers)need to back off the wave and in so doing bring back into focus the simplicity and joy that cycling IS.
What I've been waiting to hear but not want the bike industry wants you to hear. Thanks for the concise analysis!
If i was a roadie, i would probably still use disc brakes, but with a nice big rotor. Probably just as good for a regular guy, but i won't have to trash a wheel from wearing out the rims.
most road disc frames can't accommodate more than 160mm at the rear. Might be possible at the front though with an adapter
@@assaultedpeanut9 true, but on the rear you don't really need bigger disks, the braking power mostly comes from the front
@@assaultedpeanut9 usually the front cannot handle more than 160 either due to fork clearance.
Yeah. I run 180F, 160R. If they'll fit the bike, it's definitely a lot better than the silly 160 (or even 140) I've seen on a lot of bikes.
Durianrider will be wetting himself by all of this disc smack down.
To be fair, it's 90% of his content so hes probably pretty excited.
Physics always compels a reckoning. There is another design response to the heat dissipation, mechanical advantage conundrum. Larger discs. Oops, a little extra weight then. Well, two out of three ain't bad.
To be fair, the weight difference between a 140mm disc and a 180mm is quite negligible, not even 50g.
@@thomasjousse2427 yeah but aero would suffer even more .......it's like rim brakes work really well .
Froomes team is sponsored by SwissStop. Their discs are not very good compared to Shimano, so some of his issues could be solved by not using bad discs
like the shimano ones he was talking about in his vid 👍
cant wait for Froomey’s response to this video:)
Glad I kept my Merida Team bike (rim brake) and resisted the disc band wagon. Discs are a pure marketing exercise as the manufacturers are running out of ways to go to upgrade road bikes. If you have a top spec road bike from the last 5-6 years, you're not going to be faster on anything newer.
The tighter pad clearance on road discs is the main issue I've had to deal with. SRAM Rival were very problematic but Shimano GRX seem better quality and much more reliable. They're still sensitive to setup compared to my past MTBs though. Good to hear they're going to be working on it.
Exactly... I don't understand why both Shimano and SRAM are having such a small clearance and are using such a crap brakes. They have technology to avoid all of these issues. I have cheap Shimano Deore disk breaks on my cheap MTB and they never ever rubbed, I never changed oil in them and I bleed them like once and they are working flawlessly after 7 years and close to 10K of riding in all weather. Only maintenance is that I am changing pads once or twice a year (they cost like 5 bucks) and I did changed rotors this year after 7 years and I was not even out of tolerance yet I just did it as they have sales on the rotors.
I would love to just take those and put them on my road bike instead of my expensive Ultegra ones. I don't grasp how is this even possible.
You're assuming a linear lever throw/caliper piston relationship, but shimano has always used rising rates (servo-wave). They'll probably use this to get around the problem.
hopefully not. you have to move the lever 75% before you get any sort of bite with shimano xt's. before that its like they're trying to stop a train by running their fingers along the side. servo wave needs adjustability. it hasnt got it.
You’d probably want something like an S-curve in your rates: a low advantage rate to take up piston slack, and a higher but steady rate to clamp the rotor.
A couple things. Shimano uses servo wave (variable leverage), so there is "free lunch" to some extent -- it can probably be tweaked for more pad clearance, but at the expense of backwards compatibility. Also, Tektro does offer their Dorado system with thicker 2.3mm rotors (though not with road levers).
Servo wave is a nice idea, variable lever ratio, but it just doesn't seem to work very well if at all in my experience on road. MTB xt brakes, never had an issue.
@@PeakTorque Have you tried the GRX-shifters and calipers? These are the only ones that have servo-wave (on road bikes). Not perfect but close in my experience (still squeal like a pig when it's wet)
All servo wave does is alter the lever feel to take power off the caliper so that the initial bite isn't as harsh. And it wears out and rattles horribly
I mean, if heating is the issue there are so many possible solutions. Not only can water be misted into the rotor, you can use big mountain bike rotors, you can make a thick vented rotor with air cooled vanes between the rotors, like on a car, use a rotor on each side of the front wheel, etc.
But honestly, don't lose sight of the big picture. Racing motorcycle brakes work really well and they are pretty simple. If something about a bike disk brake isn't adequate, just start referencing motorcycle designs. The most obvious difference is just rotor diameter but a large mountain rotor seems like it's proportionally comparable to a motorcycle brake so I'm guessing something is getting overlooked in terms of design or materials.
@@fieldlab4 motor cycles use cast disc rotors that are pretty heavy I. E. Have high heat capacity. Bicycle disc brakes use stamped stainless steel rotors that result in inherent internal material stresses. The construction, engineering design and quality of the humble motor cycle brake is an order of magnitudes higher than what the bicycle industry attaches to your bike
I wonder if factor will be dropping a call about this 😂 thank you for the video and explaining it properly great job 👍 keep up the great work.
I wasn't much of a Froome fan but after that video my respect for him has increased massively.
Not for me. Blaming the disc brake boogeyman for the fact he's using crappy rotors.
@@galenkehler what rotors is he using? I wouldn't have thought a pro team with a maxed out bike would use cheap rotors,
@@albr4 those are swisstop catalyst rotors. Froome mentions them in his video. They're a cheap steel blank rotor.
@@galenkehler Steel, yes. Cheap -> No! It's underperformed but not cheap.
@@Hexsense it's cheap, even if they charge a lot of money for it.
I'm genuinely really happy with my road disc brakes in the UK, they feel miles better than rim brakes. But yea I don't have a giant mountain to get down. Although I have ridden at 70kph+ I've never had to stop really hard from that speed (say for a hairpin turn). So I can see that it might be a problem for Froome
Great post.
For 90% of Riders discs are absolutely the best option.
The rest are real Pro's and pretend Pro's who can simply use rim brakes.
Unfortunately, it seems to the cool thing to trash disc brakes, so all the Sheep are onboard and they just won't stop whining.
@@SaintKimbo Agreed. They can simply use rim brakes and even be very glad that others use "worse tech" disc brakes because they'd win more races. But for some reason, they are mad about all this.
Absolutely agree, I have bikes with rim and disc brakes and disk brakes I find so much better on British roads with often steep short drops with blind off camber bends. If only they didnt honk under load so much
@@StopTheRot
Thanks for the laugh, Bozo.
Maybe I ought to change the discs out for rims on my Ducati, jeez they might "depressurize" and start rubbing and stop working !
If they "COULD NOT get their disc brakes to run smoothly" I think that they probably should go to Flinstone style brakes, 'cause if they are that mechanically ignorant, even rims would be a major mystery to them and they'd probably fuck them up too !
Be honest and admit that you are only against disc brakes because your Pro heroes don't like them and you are like a scared little boy, too afraid to be seen to be different from the rest of the drooling sheep.
Fearless forecast: 4 piston calipers will be on road bikes in a few years.
actually good idea if it will be on front wheel only :D
Does not help for thermal issues
Or dual disks on the front.
@@Fetucinee oh I like this. You get to sell new levers, forks, hubs/wheelsets and brake calipers! Basically you can sell new bikes!
@@maxgrass8134 more pistons, more oil and surface area for the heat to escape plus the larger contact patch and brake pad I think you'll find they do help.
Bigger master cylinder not longer lever throw . That's basic automotive engineering
That's where the decreased leverage comes into play though
Weight weenie will complain of the added weight and bulky shifter hood now lol
Who needs brakes anyway? All they do is slow me down
@@Morpheas001 makes me wonder why don't weight weenies just ride fixie all the time
lol...and where does the added effort (mechanical advantage) come from? You can't create energy out of nothing.
Just recently discovered your channel mate, loving the fresh take on all things cycling. More MTB content!
I've had disc and rim on a tcr like you and prefer the rim bike. I had issues with the discs rubbing and a leak from the master cylinder which almost wrote off my sportive the shifter was replaced under warranty but wasn't fun loosing my front brake on a descent.
Huge respect to froome as I totally agree using both on the same bike. Personally I'll stick on rim as long as I can. Alloy wheels in winter and carbon wheels in summer been perfect so far.
if you're gonna go mechanical, disc brakes can still be better than rim brakes on carbon wheels.
Go for it. People can keep using rim brakes and inner tubes and horse drawn buggies as much as they like. Knock your socks off - in the meantime, I’m enjoying brakes and tyres that work much much better.
@@froggy0162 I don't use inner tubes I'm using a tubeless set up reguardless of it being disc or rim. Assuming rim brake users only use inner tubes is just stupid...
Also a 28mm gp5000 tyre for example will work idental reguardless of the brake type 😂
I can lock up my wheels on either bike so why I need better brakes is questionable imo... The issue is traction which is the tyre not the brake.
I'm old enough to remember racing with Wienmann brake levers that had two lever positions, which was very useful if, for instance, a slightly untrue rim caused rubbing during a race. I wonder whether a two position dis brake lever, allowing a rider to temporarily increase the gap between pad and disc without stopping, might be a marginal gain worth having.
In my opinion and what I see is, disc brake bikes are just more practical especially on long endurance rides or city riding/bike to work. Rim brakes are just easier to maintain, easier to fix, just easier to work on. Both can be used for racing, obviously, but rim brakes has and will always be reliable, a tad bit lighter, and it just works. I honestly got no reason to upgrade my rim brake bike other than the thought of having to replace my wheels every two - three years.
Haven't yet seen a video of yours that I don't find interesting. Thanks so much.
At the risk of sounding like a "save the rim brake" dork, (and being closer to a dentist than an engineer...) I think the real missed opportunity was Direct Mount rim callipers. Such a good, solid braking force and light! Not disc brake power but more effective than standard single bolt rim brakes... but the industry moved towards discs the at the same moment DM brakes became a viable option.
I had integrated rim brakes on a 2015 BMC Time Machine TMR01 with a set of 2020 Mavic Comete Pro SL wheels + yellow swissstop pads. I remember I was with a friend this last summer and got stuck in a downpour, and I'd be hitting the brakes half way from one stop light to the next
One second has passed: NOTHING
Three seconds has passed: NOTHING
Five seconds has passed: Starting to bite
Seven seconds has passed: We are somewhat slowing down
Ten seconds has passed: we're almost stopped
Legit useless in the wet. If you use alloy rims it's nowhere near as bad as carbon, but it is still very scary. If you ever plan on going with carbon rims imo go disc, that way your rims also aren't wear items.
@@YuriThorpe Direct Mount rim brakes =/= Integrated rim brakes.
which is what froome had on his pinarello and sky/ineos seemed to be insistent on them keeping, together with threaded bottom brackets
I don't want my rims being a consumable.
@@sabamacx So you're served as a consumer. You have nothing to complain about. You're probably a braver cyclist than me, riding in all conditions too! The industry refuses to let the rest of us continue to have what we want.
Mmm I think I’ll nip out and fit some nice callipers to my car!!
There is free lunch! Shimano calls it "servo wave" and I think other companies use the same system. Basically it realizes different leverage ratios during the free stroke and on the contact point. In the MTB world it has been around for years. Some people don't like it because the brakes have "less modulation".
I find disk brakes to be very reliable (rubbing is easily fixed, I'm not sure how/why they'd warp) but I think for MTB the #1 requirement is smooth, textural brake feedback to deal with adverse traction. It's honestly the hydraulics that have changed it.
If you have heat issues with disc brakes, won't you have heat issues with rim brakes? Especially with carbon wheels? Yes, mountain bikes may go slower when using brakes, but they get used much more often.
Not necessarily because they have different masses and different surface areas
I think the issue Froome is remarking on is that you can have piston retraction/travel issues and warped rotors. In a comparable scenario rim brake calipers won't cease to retract or apply themselves evenly and rim brake tracks won't deform to where you end up having rubbing on the brake pads. Even in the case of some issue with rubbing, rim brake calipers can quickly be adjusted while riding to resolve the issue.
Granted, I'm not remarking on the issue of brake track wear, brake pad wear, or issues with heat on the tires/tubes because Froome likely has little concern for those things as he gets a fresh set of pads and wheels whenever he needs them. I'm also not a rim brake evangelist either, I prefer discs; however, I am a MUCH different use case than a professional (12 hours a week vs 24 hours or more for a professional), and my equipment will wear very differently.
@@DanKolan I am not arguing with that point. That is one frustration with disc brakes. If there is an issue, you cannot simply reach down and open the brakes a little. It doesn't happen every ride, but on the occasion it does, it is annoying. Honestly, if I was a tour contender, I'd probably opt for rim brakes. My comment was aimed at Peak Torque and his comments.
@@LordAus123 heat absolutely is an issue with rim brakes too. Especially with carbon wheels. Sustained braking with carbon wheels can cause the brake track to fail and delaminate.
@@DanKolan Regarding rim brake pad wear, I have heard of cases where rim brake pads heated up so much that a single alpine descent wore through the pads. That just doesn't happen with disc brakes, unless your brakes are contaminated with sand or some other abrasive.
Disc brakes might be a problem for road racing, but it really is one of aerodynamics, isn't it?
Also, do road pros really go to the point of overheating when braking? It's not like they descend constantly braking, and you very much have ways to increase your system boiling point through the use of bionol and metallic pads for instance if need be.
The constant rubbing is an other issue altogether, but it takes 2min to fix.
I genuinely think there's no point in going for rim brakes aside from aesthetic reasons if one isn't a pro racer. The sheer advantage in braking power discs offer is just too good a feat, especially if you consider all-weather applications. It's also almost completely set and forget if one goes the hydraulic way with a mineral oil system; one change of pads once in a while and that's it, there shouldn't be any need for bleeding for years to come if it's been well set up.
This. And disc systems stay cleaner while riding in dirty conditions and inclement weather.
Honestly, coming from MTBs, no, it doesn't always take 2 minutes to fix. There's a plethora of reasons why the disc is rubbing. Is the caliper centered, is the disc straight or bent (it does that by itself through time), are all the pistons moving or are some of them dirty? How is the pad spacing spring handling pad wear (some are too stiff at the top, causing the pads to not come together at the top and causing uneven wear, etc.), what is the pad spacing actually (it can change on the same system from time to time), etc.
@@Primoz.r I agree with you partly, but most of the time, if your caliper is centred, the rubbing will be due to a bent disc, which is quite a quick fix.
Never had a problem with pads spring though, I suppose I'll see as time goes by. Regarding the changes in pad spacing, how could that arise exactly?
@Pablo Morales Sure, but you've got systems to assist with that like Ice Tech and Freeza. Also, you should simply never arrive to the point your disc overheat in the first place; if you follow the best practice of braking in small amounts periodically instead of smashing on the brakes uninterrupted, the brakes have plenty of time to cool off in between each action.
@Pablo Morales But high-end rotors aren't just pieces of steel though. They've got radiators, vents, etc. to dissipate heat and cool faster.
Warping will occur with any rotor to some degree, but if Froome, or any roadie for that matter, manages to overheat theirs, I'd say that they don't really know how to brake with discs yeah.
A rim brake job requires a alan key. A disc brake job requires a expensive bleed kit, fluid, pads, rotor alignment tool, youtube, google, and a wasted weekend.
The clearance between disc rotors and pads is governed by the retraction of the piston which is controlled by the piston seal and the design/shape of the groove in the caliper that the seal fits into
can you talk about his comments regarding o-rings making the chain more stable with larger mech cages i.e. ceramic speed?
I think it is the other way around...the larger pulleys giving the oval chainring more slack to turn over....go listen on froome video again
@@hippoace If the oval ring is symmetrical, the chain length needed to wrap around it won't change at all while pedalling as the chain will be wrapped around the half of the chainring in front of the BB axle at all times, which will always contain half the teeth of the chainring. If the top and bottom runs of chain are significantly off parallel there will be a slight effect, but not a lot.
I think Disc's are good for wider tire set ups say 30mm or wider. I like 25mm on the front and 28mm on the back. I also live in Holland so rim brakes make perfect sense to me. Great video PT I'd like to more on this topic.
Except the constant rain and damp ground in Holland makes rim brakes a nightmare, to the extent that I gave up my carbon rim brake bike and moved laterally to an aluminum hydraulic disc brake bike, both R7000 105s. Even with direct-mount calipers, it's hard to stop after a rainy afternoon on the Dune of the Hague. I can't even remember when is the last time I come home with wheels not coated with brake dust on the rim bike.
@@huwillysh I agree, For touring bikes they make sense as well especially in the winter.
Discs vs rim is like when 911s went water cooled. Better in every way but people lost their shit.
Even if you only think discs are equal in terms of performance (not true they are only close to equal in the dry) the fact the wheel is no longer a consumable makes discs a no brainier.
Wheels on my bike have a lifetime warranty, hard to do that if I’m wearing it away every time I brake.
Appreciate you solid explanations.
And yet I never experience fade on my disc road bike, but do sometimes experience fade when riding MTB trails.
It's all to do with the weight(mass) you are trying to stop..... Mtbs weigh considerably more than road bikes.....
Especially the ones weight weiners ride...
@@markstorer7204 Compared to the weight of the rider the weight of the bike barely counts in either case though. Most road rides are long periods of not braking at all with short periods moderate braking and very few extreme braking events. A MTB trail is often nothing but extreme braking events one after another with gravity assisted acceleration in between, combined with a healthy dose of contamination from mud and dust, so the brakes on a MTB take a lot more abuse.
Froomey also mentioned a lack of stiffness in his integrated bars. Do you think maybe that might come from the lack of supporting material at the t joint of the bars? I would guess it's hollow there, contrary to a separate bar and stem which has extra material to support the clamping forces
That is probably just an issue of the model, not integrated bars in general. I have used the Syncros RR1.0, which is amazing in all aspects, but also had some mileage with the Canyon H36 which is so elastic, its probably better suited for dogs to play with.
@@szalaydaniel8631 strange because my h36 bars have been pretty stiff. What year did you get yours?
pros be like: disc brakes are too heavy ... and then have to put weights in their bikes for the UCI limit
whats your opinion on open mould carbon frames hongfu, dengfu, velobuild etc?
We need to go back to putting our foot down and using our heels to stop , never failed me in the 80s and I had crap shoes
the flintstones family
Well said. I wish rim bikes were still popular
They are in my house.
They are at my house 😊
Good thing is some high end rim brake wheels are getting cheap
They are... but it's not about what the majority want... it's what the powers that be want.
See the US election for reference...
I'm under the impression they are.
Ok just face it, disc are heavier but more effective in rain, rims lighter and competitive in dry condition.
What really matters is tyre grip. If you could lock up ur wheel with a same pulling...then not much differences.
Wish I'd recorded a conversation similar to this I had with a hydraulic brake engineer many years ago when bicycle disc brakes were still mostly a dream. This guy (from Magura perhaps?) claimed a hydraulic disc caliper and rotor system that would actually deal with the heat developed by roadracing bicycles would require far too much mass (as in WEIGHT) to be marketable, while anything less would simply be dangerously inefficient. But here we are, wonder where that guy is today?
mate, awesome !
To me it seems like the weight weenies are the problem bot the brake itself. Sometimes you also do 60kmh on a MTB 😁
Always interesting to watch and listen to your videos.
For my most recent bike I was talked into going disc rather than rim brake, primarily on the benifit of better braking. Being old and slowish - 35ish klm/hr is a good speed for me on the flat - my seat of the pants experience has been just that. My speeds and my rides may well be more directly comparable to a mountain bike in terms of forces and heat disappation.
Again, thanks for the thought provoking videos.
Servo wave, man. There's no downside to less mechanical advantage in the travel range before the pads contact the rotor. I assume Shimano will add a little cam as they do with the mountain bike levers to have adjustable leverage. That aside, the solve for road disc in general is just bigger, thicker rotors. They started at 140mm (hilarious) and now, five years on, 160mm is the standard. It'll be 180mm or more soon. The cooling rate for the calipers (and the little pad fins) just isn't high enough for that mass to make an appreciable difference (especially when it's trendy to hide them behind fairings).
Love my disc brakes - don't seem to have all these issues. I maintenance myself and follow manufactures guidelines. Its not always the brake thats the issue
Average riders don't obviously
@@markwells8798 why are you such an angry man..........instantly move to personal insults for no reason. You may need to see someone about your anger issues
Disc brake development will continue off the charts. So much so all the current disc frames will be obsolete cause they will need different mounting spacing. So you need to buy newer frames for better disc brakes. We are just chasing own tails.
I don't see what could be next once flat mount becomes ubiquitous. There isn't much to add to that, is there?
@@thomasjousse2427 you are assuming current flat mount system is the end game. They could easily change the spacing or come up with clever ways to integrate caliber cavity into the frame, therefore making current frames obsolete. Goal is to make people buy new bikes. I see a new Rose bike already has the bolts inside the frame out of air turbulence.
Cool video! I’d add two arguments for discs on road bikes:
better cooling because higher speeds mean more air passes over calipers/rotors
Less braking on the road then MTB. Even on long alpine descent you hit the brakes and then let them cool. MTB descending there is almost no time you are completely off the brakes.
Carbon-carbon brakes seem to function quite well in F1 at high temperatures.
Just putting that out there.
I, for one, welcome our new carbon overlords.
Flip side of that is that they are not very good when below that high operating temperature window.
Eh, I don;t really have issues with either but I flex rim brake bikes enough that I do get wheel rub on the brakes pads if I'm out of the saddle sprinting or climbing. People worry too much about this shit. Rim brakes are fine, disc brakes are fine.
Tell that to the Rires Of Japan guy 😂
About pad clearance vs force multiplication: the "Servo-Wave" mechanism was created for this exact reason which effectively introduces a lever ratio increase as a function of lever throw. As far as I'm aware it's also being used in road levers. In assuming that Shimano will compensate for the detrimental effects at least partially by increasing the "servo-wave" effect (steeper curve/more ratio change).
I always wondered why it has worked for MTBs for years but there are so many complaints with road bikes. Frankly, I think for the average rider like me the disc brakes don't have an issue. I've never had them rub past initial setup and they stop me better than my rim brakes. But I am not pushing my riding to the extent of a pro racer so I'm never going to see those issues they complain about. And frankly, I feel that most everyday riders out there complain about it because that's what the pros complain about. Just the same with weight. Great explanation. Thanks.
I hear your lighter when you can't stop!!
Road calipers are pretty crap but what would stop you from mounting a MTB caliper on your road bike? As long as you use a post mount to flat mount adapter you could probably reduce the problem.
In the early days of road disc, the two disciplines shared the Post Mount standard. But then I suppose Shimano decided that this was too user friendly having cross compatibility between road, CX and MTB...
@@jackhammer40k_ Shimano have released a flat-mount XTR caliper. Surely that isn’t less powerful than the post-mount version. So don’t think it’s just as simple as saying ‘mtb calipers are more powerful’.
@@mf0u3021 I wasn't making that claim. I'm more decrying bike part manufacturers making "innovations" in the name of progress when it's quite transparently in their best interests and not in those of the customers'.
@@jackhammer40k_ sorry yeah, I was replying more to the initial comment, but funny how they’ve now added flat-mount support for mtb as well 🤦♂️
@@mf0u3021 Didn't know Shimano made a flat mount MTB caliper that's why I mentioned the adapter. The reason I figured MTB calipers might improve braking performance is that they have more thermal mass, not because I thought the style of mount would influence performance.
Nice logical explanation. In my experience MTB does often achieve higher speeds than you say, but the thermal issue does not seem to arise because MTBs seem to have more appropriate disc braking system - even the weight sensitive XC gear. I think in time the specs will improve to provide better/more appropriate disc brakes on roadies.
I have riding shimano ultegra disk brakes on my road bike for 2 years. I am a 90 kg rider. I have never experienced “constant rubbing” or uneven caliber retraction issues. The hills near me are only small with relatively short descents of less than 10km and I get frightened when riding faster than 70kmh on public roads. I have never had an overheating or stopping issue. I recognise that it could be a problem with real mountains and have watched a car go over the edge with brake failure in the Australian Alps when they used their brakes for a 40km descent rather than engine braking. I love the better rim design on my deep rim wheels because there is no need for a brake track and I also love being able to stop in the rain.
I am going to go against the flow here. I don’t see why people have issues with disc brakes. I have 3 bikes with discs. 2x Dura Ace and 1 Ultegra. Of the 3 1 made a noise 2 didn’t. I centralised the callipers, and swapped the wheels between 2 bikes neither bike made a noise, I then swapped them back and the noise has gone. There are less moving parts on disc brakes and less service requirements. I prefer discs to rim brakes and will never go back.
Changing discs and pads is more service requirements than replacing brake pads, which is more wearable parts, which is more money, which is why they're selling them as standard now.
This is against the flow. You are on a train going the wrong way.
Bike industry was so much in a hurry and so greedy that have not taken in to consideration safety before releasing weight winnie disk brake designs.
It would be better to give the choice of rim or disk in the future, at least till they come out with an all around sound system.
If you need disc brakes then ride them🤷
@@fergusdenoon1255 The fussiness of disc brakes is greatly exaggerated by people with little experience. Maintenance is different, but not difficult.
You almost never have to change rotors. I literally have 10s of thousands of kilometers on my rotors. On my mountain bike they are getting a bit thin, but that's ok, it is 8.5 years old and the bike will be replaced soon. I never had to change them on earlier bikes, too, they all were lifetime-of-the-bike parts. Even for people who ride more than me, I don't think you have to change rotors often … unless there was an accident or they were contaminated.
Yes, brake pads need to be changed, but that isn't more of a chore than changing rim brake pads and centering them; you can skip the last step with hydraulic (disc and rim) brakes, because they are selfadjusting, a huge bonus. The only thing that is easier with rim brakes is to judge the wear of your pads - you can do that on the bike with rim brakes. Disc brake pads aren't more expensive than rim brake pads. I reckon disc brake pads are cheaper than rim brake pads for carbon rims, though.
@@maxlein1246 I have both, I've had to change 2 rotors, both buckled from being hit by branches, meaning a long walk home.
There's pros and cons to both, there's much more con with disc brakes including them being attached to the weakest parts of the frame, rear stays receiving downfirce in a construction designed to take up force. I also prefer the more refined braking that comes from rim brakes.
I designed and made a road bike that has rim brakes integrated in the frame and forks so it doesn't even look like there are brakes on my bike, can't obtain such lines with disc brakes.
I get it, but the (non existent) wet braking on my carbon rims is downright dangerous. Plus theres the wear on those very expensive rims. Reluctantly, Im going to discs next purchase.
Just ride aluminum rims. They just work and they're relatively cheap to replace.
Would be interesting to run the numbers on the aerodynamic drag induced energy losses, ie how much of that 70kph equivalent energy actually needs to be scrubbed by the discs and also how much the extra cooling of the 2x wind speed over the calipers / disc gives you.
Well explained, let's hope the right people see this.
Having a larger reservoir to compress under the lever means you don’t have to have a bigger lever travel. It’s easily designed.
And less advantage over the caliper
Maybe 4 pot caliper can compensate for lesser power
4 pot calipers usually mean bigger pads. Bigger pads mean better heat absorption, but more surface area decreases clamping force, so you end up needing more leverage (longer stroke at master cylinder) to equal the same pressure as a smaller pad. Heat's a big deal though.
The extra friction surface does help out too, but I don't know if it adds anything. You get what you put in.
🙌👏👏 Would i run a 180-200mm setup if i could, hell yes I would. Being limited to a 160mm setup is my biggest gripe about road disc.
We can thank shimano and their post mount system for that! Larger discs are available on OS Mounts
Anyone complaining about the weight of current road bikes wasn't around before carbon fibre took over from aluminium, titanium and steel.
If we're going to argue against disc brakes based solely on weight we could equally argue against sti levers, electronic shifting, deep dished wheels etc.
1) I feel for RoJ the moment he will watch this video.
2) Non te la cavi male in italiano. Ti do 6.
3) Wouldn't you agree that you are downplaying (a tiny bit) mass? Between a bike and a Vespa there is still a significant difference. Assuming a 10kg bike, an 80kg rider and a 100kg scooter, the energy required to stop the scooter will still be double at any given speed. If anything, the main take-away for me here would be that the bike weight per se has only minor consequences To me, that matters for bike touring for instance, in the sense that if a given brake system will perform well when the bike is unloaded, it will perform almost equally well even when that same bike is full of panniers.
Finally, if you ask me the one "crime against humanity" bike manufacturers committed was to go for this damn flat mount standard and its limitation to 160mm. I would spec 200f/180r on all my bikes, tomorrow, if I could.
The speed argument is nonsense, the average(!) speed in Maribor in the world cup (downhill) was over 50 kph across the whole track 10 years ago. 29ers should increase that, but sadly it was kinda wet the last two times the world cup has gone there. And the speeds are not that high just there. Plus not everybody goes 60 kph on a road bike.
Then there's the gradient, which is usually much more severe for mountain bikes, meaning you brake longer or for a higher percentage of time. Sometimes it's hard to even let up to get some air in between the pads and the disc.
Granted, 4-piston calipers have become the norm in anything that's not XC, 200 mm rotors are pretty standard on anything with 140 mm or more travel, but still.
I'm not a roadie and don't have experience with any road brakes, but in MTB the lever throw, braking power and pad clearance has been successfully dealt with with progressive mechanisms in the levers. Unless you have a Guide/Code R which doesn't have a swing link and you're just moaning around the internet how horrible the brakes are without knowing why and throwing all Sram brakes into the same bin.
Rubbing is an issue everywhere and I fear is caused by dirty pistons getting stuck. Bellows covering it might help with the actual sliding interface not getting dirty (or being kept lubricated with grease maybe even?).
As for surface area and cooling... Start looking into Al discs? Make them 3, 4, 5 mm thick, that way they won't bend, won't rub as much and you'll have some more heat mass (Al has ~double the heat capacity per mass). It can't be impossible as the 1st gen Lotus Elise used aluminium brakes (for lightness), so how hard could it be? Also, what about ducts? Channeling air actively towards the calipers and rotors? Yeah, it will kill aero, I know... Maybe add a system on the brake line to only open the channel when you are braking?
EDIT: watched his video, he mentions that the thing works on the stand, but not on the road (rubbing & co.). Is the bike flexing under his weight? Are the wheels inserted properly? I ALWAYS tighten my wheels with the bike on the ground, so the hubs sit on the dropout ledges, in the same place every time. Even with through axles you can put your wheel in crooked. And it can cause rubbing (and shifting issues as well).
It is so much easier to go 60 on a roadbike than it is to go 50 downhill. Pointing your bike down a hill and getting on the brakes to save your bad technique is the whole problem.
I think the point about speed made in the video is valid though. The 50km/h average on a World Cup DH track you're talking about is done by pros and the finishing times are like 3 minutes.
An average road rider could easily find themselves at 60km/h plus just rolling down a reasonably tall/steep hill, also there may be some conditions on the road where you will need to be on the brakes constantly (twisty roads, poor visibility around corners, stuck behind traffic etc).
All I am seeing/hearing are an anecdotes. Sure there was some good science here but it never looked at the system as a whole. It was simply an academic exercise. Nothing wrong with that as it provides a base for imperial science to be done but until then it's merely conjecture. Someone needs to lab test the two systems side by side so we can actually see the real differences.
Two pro level race wheels, one disc one rim. Get them up to a set speed and slow them to a set speed repeatedly to simulate a mountain decent. Then test a side by side long break drag down the same decent. Then show the results of both breaking systems - play, wear, rub etc... Until then I'd have to error the side of shimano (sram etc) engineers and my own anecdotes.
Wow it’makes total sense & u made me understand it
i've had an overheating front brake on a very steep descent.
on hard breaking the resin pads went to 0 breaking performance instantly @ aroud 60 km/h
I used to be a fan of discs but this broke my trust.
System weight 105 kg
Brakes: GRX 810 Stock with upgraded 180 mm Rotor
Cannot we just go back to rim brakes?? Was there a real need and demand for disc brakes on road bikes? Just saying...
There was amongst those using carbon clinchers. As someone who has used carbon rim brakes, those things are straight up deathtraps in the wet.
@@404nobrakes you are right, rim brakes on carbon wheels don't brake well the first 10 metres in wet conditions. But was there a real need to stop offering rim brakes bikes???
@@kikal85 It's really expensive to offer 2 identical bikes, one with discs and one with rims. It's far more profitable to convince everyone that they need discs. Don't be surprised if new top end groupsets become disc and electronic only. It saves a lot of development cost. 1 groupset instead of 4.
@@404nobrakes man you're really depressing me here :)
Wrong. Disc brakes work wonderfully on road bikes.
Regarding Caliper vs Lever throw ratios: can you address that by making the actuation non-linear? You can have the first 10% of the Lever movement be responsible for the first 90% of the caliper movement and then you have a full 90% of your lever movement left to use on your actual braking
Look up Shimano servo wave - Shimano have been doing it in various forms since the 1980s.
Maybe they will have a system where the mechanical advantage get's higher when the pads contact the disc
it's called Shimano's Servo-Wave tech
That's all well and good but still disc brakes are forced down consumers (and the peletons) throats for nefarious reasons. Manufacturers could just offer both options and let the consumer decide. There are some shady business practices going on here.
I suspect all those who love rim brakes much have never worn through brake track on their wheels with the abrasive paste that comes from winter commuting on gritted roads. I think the power that disc brakes have is actually way more than is needed at the moment (obviously grip strength dependent) so I think a less powerful brake with more pad movement would be great.
I think on fully mechanical brakes like trp spyre. It would be easy to make the pads move initially faster and then the speed changes to more power when pads get closer to disc. When I took my trp brakes apart for cleaning and re lubricating, there were 3 pall bearings inside on ramps in slots. when the ramps move, the palls push the ramps away from each one. If the ramps had a curve.. at first deep ramp and then goes more shallow. It would solve the problem with too little clearance. Braking power would be same, free play of lever would be same, but the clearance would be bigger.
Mechanical discs like an Avid BB7 really do solve this problem allowing the user to adjust the piston throw themselves allowing you to balance the lever feel with risk of brake rub. Mechanical advantage remains the same no matter the adjustment. I assume hydraulics win in mechanic advantage which is why they have better stopping power?
I have BB7 on a commuter bike I built to look old school with barcon shifters, polished alloy, etc., but stop when I get a red light barrelling downhill in the endless Seattle rain. I have Shimano hydraulic on another bike. The Shimano hydraulics are MUCH nicer! They are self adjusting with wear, center themselves better, and break better.
I live in Japan and ride mainly in the mountains here. Since there aren't many particularly nice aluminum wheelset anymore I like the trade off of disks with carbon rims for long descents since I don't get wheels for free. Have had very few issues with rubbing, but many riding buddies do. Maybe I just got lucky!
Maybe the bike industry could learn something from the car industry.
The faster your car, the bigger the discs. One reason that car wheels on sports cars are getting bigger is to accommodate bigger brake disks. That is also the reason that tires are getting lower in relation to their width, so that the internal diameter of the tire/wheel combination grows even further. To make the brakes stronger they went from 2 pot (pistons) to 4 pot to even 6 pot on bigger/faster cars. To counter the heat problem the discs are ventilated, meaning that they are double with ventilation channels in between the layers.
What do you think of what Hope Tech are doing adapting their MTB brake calliper to a road setup with the RX4?
I just ordered a new Oltre XR4, with RIM brakes,.... the bike shop owner and former 80's pro, said, ohhh, you made the right choice.
So glad i put mountain bike discs on my hybrid instead of little wheeny ones.
The free snack comes from servowave. Non linear pad travel vs lever travel. This way you can have the extra clearance and very low braking force in the "empty space" until the pad contacts the rotor.
My guess is Shimano's probably going to use a goofy lever design that has more piston travel at the start, and then more mechanical advantage at the end.
It'll give people "powerful" braking without rub, but it's also probably going to be very sensitive to pad wear, and tougher to modulate.
I'm not competing with my bike, so my standards are probably a little different, but I put some biger rotors 180F/160R, on a set of TRP Spyre cable calipers, and I think they're pretty ideal for a non weight-weenie road bike.
They're actively pulled away from the rotor by the spring, which fixes some of the causes of rubbing and, the slightly larger rotors make up for the reduced mechanical advantage.
The only downside is that you do need to give the pad adjusters a quarter turn with a 3mm allen wrench every few weeks when the lever travel starts to get excessive.
My mountain bike, and cargo E-bike have hydraulics, and big 203mm rotors, and while they stop very well, I do get tired of them rubbing, and replacing pads that are unevenly worn because one piston retracts better than the other, etc.
That said. I'd still rather take all the downsides of them over a rim brake that's going to chew up my rims and triple my stopping distance any time there's a little rain (I live in a very rainy city).
The issue with fitting larger rotors is that they further compromise aero and increase the already impressive ability to catch crosswinds. I regularly ride in crosswinds and swap between a disc setup consisting of a 160mm front rotor and 45mm deep rims and rim brake set ups consisting of 50mm deep rims. It is surprising how much more the disc setup suffers in the crosswinds. It seems in the quest to fit disc brakes more problems and compromises are made than solved. If a problem existed in the first place?
the noise of disc brakes alone is enough for me to not want them, total buzz kill
Okay, so car and motorcycle discs rely on the square section seal on the piston being deformed and returning to shape to retract the pads. The section of a seal on any pushbike is not sufficient, hence the extra spring which you never see on an automotive application.
If you want to see a solution to braking force and heat dissipation, check out a Buell motorcycle. They use a 'perimeter' disc and can get away with a smaller calliper, also single sided.
I want to my experience (or should I say, anecdotal evidence) to the discussion. I went on a bike tour to the Alps. I have descended Stelvio and Mortirolo on 2015 MTB disc brakes, and the brakes didn't fade and I'm here to tell the tale. I had heard of tire blowouts in rim brakes but I think it is largely inexistent with modern alloy wheels, because one of the riding buddies was terrified of descents and dragged his rim brakes on these 15-20 km descents, with panniers on, and no blow outs happened. I would suppose modern road disc or rim brakes don't fade or blow out as often as it seems to be implied in the discussions.
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