Are Disc Brakes Faster? Disc Brakes Vs Rim Brakes | GCN Does Science
Вставка
- Опубліковано 15 лип 2017
- In association with SRAM.
Simon's had enough of the debate, he wants to find out what really is the best, rim or disc brakes?
Subscribe to GCN: gcn.eu/SubscribeToGCN
Get exclusive GCN gear in the GCN shop! gcn.eu/h9
Let us know what you think of this massive amount of data in the comments below 👇
To ensure that the results are as accurate as possible, the frames are the same (Orbea Orca), the tyres are the same (Continental GP4000s II), and the riding position is the same.
How is the test going to be conducted?
Once in the dry on each bike and once in the wet on each bike. So a total of four descents.
The location for the test is a portion of the descent of the Passo Pordoi in Alta Badia, Italy.
How are the results going to be gathered? Simon will be using GPS data from his Wahoo Elemnt, Powermeter data, heart rate measurements, and an accelerometer.
Were disc brakes faster? Well, you are going to have to watch to find out.
If you'd like to contribute captions and video info in your language, here's the link 👍 gcn.eu/h9
Watch more on GCN...
Are Disc Brakes Ready For The Tour De France? Road Disc Brakes Vs. Rim Brakes | GCN Does Science 📹 gcn.eu/1e4VmLZ
How Much Faster Can You Stop With Disc Brakes? 📹 gcn.eu/1LbBHJ4
Photos: © Bettiniphoto / www.bettiniphoto.net/ & ©Tim De Waele / www.tdwsport.com
About GCN:
The Global Cycling Network puts you in the centre of the action: from the iconic climbs of Alpe D’Huez and Mont Ventoux to the cobbles of Flanders, everywhere there is road or pavé, world-class racing and pro riders, we will be there bringing you action, analysis and unparalleled access every week, every month, and every year. We show you how to be a better cyclist with our bike maintenance videos, tips for improving your cycling, cycling top tens, and not forgetting the weekly GCN Show. Join us on UA-cam’s biggest and best cycling channel to get closer to the action and improve your riding!
Welcome to the Global Cycling Network | Inside cycling
Thanks to our sponsors:
Alta Badia:gcn.eu/AltaBadia- // Maratona Dles Dolomites: gcn.eu/MaratonaDlesDolomites-
Assos of Switzerland: gcn.eu/Assos
KASK helmets: gcn.eu/KASK
fi’zi:k shoes and saddles: gcn.eu/fizikshoes and gcn.eu/fiziksaddles
Topeak tools: gcn.eu/Topeak
Canyon bikes: gcn.eu/-Canyon
Quarq: gcn.eu/Quarq
DT Swiss: gcn.eu/DtSwiss
Science in Sport: gcn.eu/SiS
Orbea bikes: gcn.eu/Orbea
Trek Bicycles: gcn.eu/-Trek
Vision wheels: gcn.eu/Vision
Zipp wheels: gcn.eu/Zipp
power2max: gcn.eu/power2max
Wahoo Fitness: gcn.eu/Wahoo-Fitness
Park Tool: gcn.eu/-parktool
Continental tyres: gcn.eu/continental-
Camelbak: gcn.eu/camelbak-
UA-cam Channel - gcn.eu/gcnYT
Facebook - gcn.eu/gcnFb
Google+ - gcn.eu/gcnGPlus
Twitter - gcn.eu/gcnTW
Leave us a comment below! - Спорт
Which would you choose? let us know 👇
dics
Mr.ActionGal101 dicks? Its 2017 thats alright :)
Coming from mountain biking, I really enjoy the feeling of disc brakes. I'm currently using rim brakes on my road bike, but I would switch to disc brakes if I could.
Global Cycling Network disc with thru axle all the way
Global Cycling Network always preferred disc, harder initial bite and better feel. Rim brakes in the wet on fast descents can be a total lottery but I agree they are reasonably similar in the dry
my wallet says rim brakes are just as fast and good as disc brakes
haha yeah²
They Live We See hahahaha my wallet says the same
I remember having a BMX with disc brakes when I was a kid
"Backpedal brakes" (as I called them) made it so easy to lock up the back wheel and leave a huge skid mark on the road lmao
Sure, until you wear out the rim braking surface and have to replace it. An event that will never occur with a disc rim.
@@gaveltron you can buy a new alloy rim for around $20 (where the braking surface won't wear out)
Rim brakes still win
A simpler test would be to just set up a piece of flat tarmac do repeated practice braking from a 50 km/hr sprint to 0. The data would be much easier to dissect and you'd have a static video you could overlay to see if you're actually getting on the brakes faster and getting to maximum braking force sooner with discs.
That would actually be a fairly basic yet decent test, removing a lot of variables and at least proving something
Stephen Forsyth that’s exactly what I was expecting. Unsure why they didn’t do that.
They did that a while back. But it does not test all variables (aerodynamics, weight, suspension) . Both systems can freeze the wheel and stopping power is down to the rubber from that point on. Would not do more that testing tyres.
Ive always felt that Consumer Reports as biased not by anything but sensationalism. Is the measured difference significant? Or does is simply need the benefit of statistical signifying? If we portrayed facts w.r.t. $, it seems no amount of signifying would be sufficient, but we are a creative bunch. There seems to be no limit to what is portrayed as "scientific," when $ are not part of science. What $ value is disk? Heck we can't even say that, but we need to consider how to "analyze" the data? My kids - no dinner, bed after well deserved brestings ( with a high pass tranformation).
This video is an excellent example of the state of science....and why it should be questioned and not held in such high esteem
The one factor I like about my rim brakes on metal rims is the mechanical feedback I get through the cable to my brake levers. That feel tells me what is happening to the connection of my brakes to the rim, rim to the tire and tire to the pavement when I am controlling my speed. My racing days are long over but I still ride my road bikes. I am still feel confident with the speed control I get with rim brakes. My commuter bike has disc brakes but I never use that bike like I use my road bikes.
I brake my bicycle with my feet (wearing flip flops) press to the wheel.. if i crash, i crash like a real men
Facts
HAHAHAHAA
I am sure your husband worries about you being foolish
Welcome to Jackass
So... rim brakes then? :D
That's editing at 6:05 though!
Hey Simon,
Fourier transform the accelerometer data and filter out the high-frequency components. You'll be able to remove the road chatter and vibrations and better distinguish the rim v. disc patterns. Upload the data and I'll even do it for you guys.
Lu Huang yeah was gonna say I doubt they know how the Fourier transformation works ^^
Fast Fourier Transforms and DFT's are for nerds!
Just do it in Excel
How about just releasing the data files and letting the community have a go? The iPython notebook awaits!
No need for Fourier, just put it through a low pass filter.
Nice job guys. Aside from the performance, it may also be worth mentioning that rim brakes are lighter for climbing, and easier to travel with when you need to disassemble your bike. Personally I really like the rim brakes on my carbon Deda wheels - unless it's wet outside, then it's an utterly terrifying descent back down the mountain!
You should do this again with aluminum brake tracks, since most of us have alloy wheels. Very interesting.
Just posted the same request. Same high quality aluminum non aero rims which is what the majority of riders prefer
But most people have a concern about carbon rim wheels. Alum are known to be better than carbon for braking
I really like the way the videos are produced lately.
Agreed! Great editing and recording!
Agreed
Must be the disc brakes :P
Faster, no, brakes don't add speed. However, they do decrease stopping distance. I feel confident in disk, never feel that on rim brakes. I will ride full speed into a blind corner and expect my disks to stop me. On rims, I know I'm taking life into my own hands.
Is there a way to measure when you actually grabbed the brakes on each turn and when you let off, overlayed ontop of a map to see if you were breaking later with discs?
6:03 - red background, then graphics - great job, GCN! Great presentation, Si.
Why am I watching this when my bike doesn't even have brakes
Harry Hartz so u can buy some...?
just put your foot on the wheel
i don´t even have a bike :D
do you have a BMX?
Fixed gear life
Really good video. Wasn't expecting it to provide a definitive answer to the rim/disk question, but thought that it was incredibly well thought through, and well presented. Really like the fact that you understood the limitations of the test and didn't jump to any conclusions. Very intelligent and thought provoking nonetheless. Keep it up
i have rim brakes on my car
XD
I have drum brakes on my downhill bike
Cyberdemon I have radial brakes on my big wheel.
ultegra or dura ace?
I put my foot out of the door and on the ground
I would be interested to see a similar test including aluminium surface rim brakes, and the newer direct mount braking systems vs their older counterparts. But ultimately when the UCI legalizes disc brakes, my next bike will certainly have them, they just seem more versatile for us mere mortals who can only afford one bike and wheel-set.
I think thru axle is the future, which comes with disc brakes.
I've never had an issue with rim brakes on $400 wheel sets. However If I am going to drop $1,800 on a wheel set, I think I'll make the move to disc brakes. makes more economical sense
My only objection is that the industry is removing the choice for us. There’s been a big jump in the price of 2020 bikes and this is a big part of that.
Great video and brilliant editing. Releasing at least one new video a day is a tough job, but you guys nail it everytime. I like stats and data, maybe you can do a video about how much you benefit from drafting while climbing.
the production of this video is awesome! great work guys
descending on a rim-brake bike with carbon rims in the wet has got to be quite the butt-clincher.
It really isn't, as it's the tyres that dictate your ability to stop, even fat old gits like me can lock up a back carbon wheel when braking hard in the wet. If you can't modulate braking on rims then you're not capable or wanting to learn about braking full stop. it's not about outright braking power, it's understanding when and where to brake on top of your tyres grip that dictates stopping/slowing ability.
@@ynotnilknarf39 it’s not really about locking up. It’s the sheer control and precision of the braking modulation.
Disc brakes can allow you to stop harder and faster, without locking up, at a degree that would have rim brakes locking up because you simply don’t have that finesse to straddle that fine line.
A crude analogy would be to Think of rim brakes as simply jamming on the brakes and locking up, while disc allows you to hit the point just before it locks up to slow down.
@@87togabito What I'm saying is there is enough power with rim brakes to lock a wheel up, this occurs frequently with disc brake users, even Global Cycle Network did this when doing their direct comparison of disc to rim brakes a couple of years ago, pros lock up, commuter riders and weekend warriors lock up with discs. GCN then stated that after locking up and skidding on the tyres (no doubt taking some of the tread off) made discs better despite their inability to modulate in a braking test. Modulation of brakes comes with experience, I rarely lock up but will do it for shits and giggles on occasion in the wet
And if you can't see the limiting factor is the adhesion of the tyres and the ability of the rider to react or be roactive regards a situatin, whether that;s in a race or on thrun to work then you have a very limited grasp of mechanicals. People using discs just like cars with 'better' brakes brake later, they get into this habit of braking later, until they run out of room and thinking time, and then they come a cropper, just as they do in pro races and on the roads in the same number if not worse than those using rim brakes.
it is a complete fallacy that disc brakes are better regards braking and modulation, people who are in the cycling world like people in other fields, hate to go against the grain because they don't want to be exposed as idiots/not knowing anything. This happens everywhere, economy forcasters get ownward trends wrong virtually 99% of the time, why, because they go with the consensus despite the fact they might think it is wrong. Same thing with helmets which are the biggest lie and red herring regards cycle safety and actually works against people on bikes/cycling as a whole. We also have the BS regards a made up virus, governments seemingly going with a consensus on the back of false and manipulated data from the outset but to not agree is likely to put them under a lot of pressure or lose their jobs.
The only person to come out re discs who has some weight and say they aren't all that is Chris Froome. Kudos to him
@@ynotnilknarf39 why talk of experience as if it’s some holy grail, when you have modern tech to do that for you? Isn’t that the whole point of tech; to make things easier so that we can think of other things?
Anyway, I’d love to continue this discussion, but I frankly know that it’s 1) pointless since we stand on different sides and 2) 5 years give and take I’d be laughing as you struggle to find parts to replace your rim brakes.
Frankly to me, the real fun isn’t about winning this discussion; rather it’s knowing that in 5-10 years, you’d be forced to use a disc brake when your bike frame is damaged/due for replacement. That, or you quit cycling entirely. Both seem like a positive development 😂
@@87togabito Because simply ytanking on the lever with discs still means you will not be able to brake correctly and are even more likely to lock up the brakes. Jeez you newbies know naff all!
Gaining experience to understand how to brake can take a short space of time for anyone with reasonable capacity, it's the varying speeds, road surfaces/camber etc, weather and tyre type that changes frequently so the more you ride, the more you understand braking as a whole, not just being able to pull the lever and think that's it.
If you think you can just pull the lever on a disc braked bike and think that's all there is too it then frankly no point furthering the discussion!
I come from racing motorcycles and have been cycling for many years. I showed up to my LBS and Specialized was there giving test rides on all new models. I took a Tarmac Disc DI2 out and immediately felt at home, brake feel felt just like a motor bike. I was super impressed by the feel of the brakes but not so much by the DI2. I am now riding a mechanical shift disc road bike..
if you publish the data, some techie people can do more analysis. it would be interesting to get expert analysis.
Not really, you need far more than one sample under each condition to do proper statistical analysis.
Only if you attempt to analyse each run as a whole. If you consider every corner individually, that'll amount to a lot more sample points.
"The things we do for Science" - Si Richardson, with peak down.
this is evidence based argument, and added with amazingly presented scheme and explanation. One of my most favourite GCN videos, if not THE most favourite. Marvelous job GCN!
Amazing Test and Presentation! Love this channel!
I would rather ware out and replace a relatively cheap pair of discs than a super expensive set of carbon rims.
the disc rotors never wear(they wear but it takes such a long time we say they dont) on MTB's just the pads. I would guess its the same on road bikes
resin or metal pads? @ Johnny Cab
I'm certainly no pro, but I need to replace my rotors on my MTB about twice a year. Riding in mud will accelerate that process. It all comes down to what and how fast you're riding.
I would rather ride the better system (rim brake)
they wear.... in my case the rotors and pads seemed to go at almost same rate and i changed both same time
Next on Disk vs Rim Brakes, How easy is it to maintenance?
😀 I'm into that video
Im a pro mechanic, I wrench on all this stuff every day.
Discs are different, requiring new skills. Dont let anybody tell you they last longer or are less expensive. Discs are actually quite a bit more expensive both initially and later on for maintenance and parts. If you crash and require new hydro levers for your roadie, be prepared to empty your wallet!
Discs are more complex.
Hydraulic systems require special tools and skills. If youve worked on cars and bled brakes you can probably bleed your own, but the procedures are frequently more complex and much less tolerant to any air in the system than motor vehicles.
Just A VERY FEW examples of mechanical cable discs can be made to stop well!!! They need to be set up very carefully to function proper. Many examples of mechanical discs on entry level bikes are HORRIBLE STOPPERS, especially those found on road bikes! Many are WORSE THAN CALIPER BRAKES! Mechanical discs are frequently a budget minded afterthought, specced to reach a particular pricepoint.
In general MTB hydros are the best and most refined disc brakes on the bike market. Most Road discs hydro or mechanical still have issues and are playing catch up. We are still just a couple years into this road disk brake saturation in the market place.
Shimano in particular make great mtb hydros. They are the only hydro discs I really recommend.
I'm terrible at reading comprehension, would someone mind to conclude this for me please? i do get some points tho but not all coz im a newbie so i barely understand some of them, sorry 😬✌🏼
@@a1eukel road bike disc brakes haven't been refined much yet, rim brakes are pretty darn good and currently are cheaper both for initial purchase and for ongoing maintenance costs
@@danmanthe9335 got it, thanks!
@@rollinrat4850 This. People really need to realise the variation in disc brakes is huge compared to rim brakes. You can trust any cheap pair of rim brakes to stop you, but a cheap pair of disc brakes will send you straight into the ditch. I tried a bike with cheap mechanical disc brakes once and went WTF, even a $10 pair of rim brakes would stop better than it. I'd take rim brakes any day if I weren't willing to splurge out for a good hydraulic disc system
Amazing video, been trying to find data like this forever. Bravo
I didn't think the video would be this interesting. Well done on presenting, editing etc. Cool stuff.
I'd love to see the fear in your eyes when you try this with an extra 25kg strapped to your back. I'm 95kg (210lbs) and, anecdotally speaking, am quite sure there'd be a huge difference. To not die with rim brakes at this weight, you can't make mistakes. I have to ride my road bike like XC, shifting my weight way off the back of the seat, all your breaking needs to happen in a straight line before turning in, you need to nail every apex, and don't even think about touching the levers mid-corner as the data suggests you tended to do here. When I pull my rim brake levers, it goes from a mere suggestion to slow down to instant full lock-up. With the extra weight, I'm also going faster downhill (another good test) which just compounds the problems. Would love to see this explored further!
I am ever heavier than you. I am really liking disc brakes. I have two bikes that I ride, one with rim, one with disc. Disc wins out pretty much no matter what as far as flat out braking power.
I have had to play stomp on the disc to get it back to straight after the dog wiped me out. Took me a while to get the disc straight again. This is something that won't happen with rim brakes.
I have a preference for rim brakes. Just more simple, lighter, less air resistance, cheaper and does the job well. Great video
"less air resistance" lmao what a joke
How is it cheaper??
@@DrMarvinLara the components are cheap while disk brakes is costly to repair generally speaking. Rim brakes have been here for a long time so they cost less. Also disk brakes on cheaper bikes have lots of issues at one point they stop braking aka the disk gets disconnected with the hub
Awesome, awesome vid. Cheers to the video editor and Si's riding.
Probs for always putting great dnb as background music guys!
I just bought a new bike for Climbing and it has disc brakes, it takes a little bit of getting used to but I'm going to go with the feel of Breaking, you most definitely have more confidence in the Breaking ability and it will stop faster, I find you have to keep your butt in the seat or it will slide
Glen Andi leaning back whilst braking with any brake system is very effective.
I'm an Aussie, so I just put my foot onto the front tyre to slow down.
Lmao i used to do that with my old bike when my brakes never worked
I do this all the time when my brakes got removed. I still have my destroyed shoes
You and every bmx rider ever
Childhood days. Lol
That can be classified as rim break!
I've ridden all types from my cx canti's, road bike rims and lately I have been riding a bianchi road bike with discs. I recently took it up and down mount Mitchell in North Carolina, and I have to say, I couldn't imagine having nearly as much fun on my rim brake bike. As far as aero is concerned the only thing I've really felt more is crosswind, but that also could be factored with my bladed spokes and the bikes general layout. I really love the modulation of discs and the fact you can always have predictable, reliable braking on tap. The same cannot be said when experiencing rim brake fade or lockup. To me, I don't think I'll go back and at '500g' difference I think I'll just skip some snacks or train more.
Without watching more than 3 minutes of the video, I am guessing the end result is gonna be 'Results are inconclusive, but without question, both disc and rim brakes have their pro's and con's. buy sram'
Rim brakes, for me. Less complicated, and efficient enough for my kind of riding. 🤗
exactly. They are very effective , the rim is like a GIANT brake rotor.
and a lot easier on the wallet!
Same here. I'm in the market for a new bike next year. I will only be considering rim brakes. Reduces my selection but thats ok.
@@daryl4841 it sucks how hard it is to find new rim brake bikes nowadays
@@daryl4841 you could just build a bike then
My vote is disc and here's why: rim brakes on carbon rims suck! I recently I updated to carbon rims on my road bike and installed cork brake pads as directed by the manufacturer. After several months of riding, I really don't like the way the carbon fiber rims heat up and burn the pads on long descents (like this one in the Dolomiti). First, modulation is wonky and unpredictable and second I had a high speed blowout on a long twisty decent (a full on come to Jesus moment) and I think it was because the rims heated up and melted the tube (it was a new tube too). I'm trying other types of pads but if things don't improve with the heating up of the rims, I'm actually considering putting my alloy rims back on the bike. So even if discs are slower, my next road bike will have discs because I can't stand lighting my brake pads nearly on fire and risking my arse on an equipment failure. Mountain bikes have been using disc for 15-20 years, I could never ride rim brakes on dirt again.
I thought the honesty and attempt to both eliminate bias and note the bias that was not removed made for an informative, if incomplete, discussion. And your coda about the feel of the bike and the pleasure of the descent was also well said. Thanks!
Awesome production guys! Fave youtube channel
All this for 8 seconds and only when wet, even on an extremely technical descent. The number of rides where this is significant is virtually trivial for many riders, me included.
6:30 "it does look like the disc bike goes slightly faster on the straights, but also slightly slower round the corners"
perhaps thats because its braking more with the same effort, therefore slowing down more? which, since you then need more effort to recover from the additional braking, would lead to the slightly faster speeds that they saw on the rim bike. this is interesting, but as someone else mentioned, not the best way to test braking ability because there are too many variables. best to do a bunch of straight runs on a flat surface, accelerate to a certain speed compare braking ability.
Incredible video ! Wanted to exactly which is better for road use, will not need another video on this subject again.
I just bought a new city bike with hydrolic disk brakes. It is much higher quality than my old bike with rim brakes. I live in a hilly city and ride down hills every day AROUND TRAFFIC. I really don't care how fast I am, I care how safe I am. There is no comparison. Disc brakes all the way for safety.
You can be fast and safe. There are road bikes with disk brakes.
As a mountain biker, I wouldn't be caught dead on rim brakes (actually, I would, and that is the problem). But I also would never ride anything less than 2.4" tires sooooo shrug. There's a reason the mountain bike industry gave up on rim brakes 20 years ago.
johnnybikesalot…….....your argument is utterly idiotic. Mountain bikes are a completely different animal compared with road-bikes - with totally different functions in terms of terrain, technique, speeds and weather conditions. [and by the way, I have ridden and raced in both disciplines]. The most important factors in modern road-frame construction is weight and stiffness. These are both greatly compromised by using disc brakes as opposed to rim brakes. [discs add 700g-1000g to the weight of a road bike]
Aerodynamically, rim brakes are far superior compared with discs - again, another important element in road-bike set-ups. To the best of my knowledge, mountain bikes are not directly affected by these factors. Indeed the main reason mountain bikes actually require greater braking efficiency is predominantly because of the terrain [which may be muddy, rocky, uneven and heavily cambered] as well as the gradients and the sheer weight of the machines - especially if your MTB is fully-suspended.
Compare too the tyres and wheel-sets on a road bike and a mountain-bike. Even when I used 'slicks' on my mountain bike they were considerably heavier and wider than on my road bike. But at the end of the day - the biggest difference is in what you actually use the two different types of bikes for. I always used my mountain bike for 'winter-training' - as well as for fun when the weather was bad. And although I competed in endurance events they were considerably shorter compared to road-races.
I agree that discs probably 'lend' themselves far better to mountain biking than the old center-pull brake system etc. But the same rule of thumb simply does not apply with road bikes. Bearing in mind the one main benefit of disc brakes [better in the wet] to the numerous disadvantages [weight, high maintenance, less user-friendly, aesthetically ugly and cost] I know which I prefer!
@@thesoultwins72 you go faster on road bike yet you want shittier brakes? Brakes should atleast throw u over the bars yet they barely stop me. I go faster on road decent on mtb than a road bike because mtb has brakes that I can trust. road Bike industry just sand bagging with their product to sell u more shit for years to come. Releasing brakes that matches mtb for the road bit by bit so you guys would buy more product.
@@thesoultwins72 Um, not every ride is a race. Not every rider is a racer. Disc brakes allow you to use 100% of the tire grip. Rim brakes will fail far before that. And that's in the 'dry'....
@@bikebudha01 …...IF 'not every ride is a race and not every rider is a race' - why do you need disc brakes at all?!? Pretty inane argument really....
@@thesoultwins72 235lbs. 20 mile descents. Speeds in the 40-60mph range. Yeah, I can squeeze the shit out of rim brakes and not slow down. And the pads wear away. And then you know, rain. Rim brakes don't work in the rain. And rim wear, rim brakes can burn through rims. Nothing 'inane' about the realities of heavier riders, faster speeds, or wet conditions. But you know, if the extra 50g of disc brakes is preventing you from winning the tour de france, then maybe you should stick with rim brakes...
Shoutout to Si for riding in the wet and cold like that for science.
yes thanks for this video been wanting to know the difference an you were very informative in this video have a nice ride
Thank you - this helped me decide for a Bianchi Impulso with rim brakes and saving $600, which was the upgrade cost to disk - I never ride in the wet. Awesome video.
Martin Buena-franco never is a long time
love the d&b music lads!
they should make this test *blind folded*, then Simon can remove bias 😁
#YeahScience
Cool explanation . Like it . Thank you for the data .
One thing to also think about is with rim brakes on a long descent like this your rims are going to get hot. This heat is going to make your tire pressure go up, so starting at 75 psi your tires may have been more aero and have less rolling resistance.
Loved the video by the way!!
Rim brakes have suited me fine for the most part, on both trails, mountains and bike paths. If I felt there was a need for better brakes, I would just replace the worn out brake pads. But generally speaking, the less I brake the faster or more speed I gain. So having disc brakes is more or less a non-issue.
Ride at 30kmh, 40kmh & 50kmh (over the same stretch of road) brake as hard as possible and see which bike pulls up quicker. Easier more reliable test?
That is true u smart.I was thinking the same thing
You'd lock up the tires in either scenario, so what good would that do? The point of discs is that you have a dedicated surface for heat dissipation, and so they won't fade as much, you have better modulation, and it allows for better engineering of a specific braking component rather than tying braking to the rim of the tire.
I really enjoyed the content of this video. But the video production and editing took it to another level.
My Madone 9 with rim brakes on the Vision carbon wheels is SO BAD downhill (and I'm 95+kg) that I actually avoid descents with tight corners on it. It was made to go fast on the flats/rolling, so that's where it lives...
great job but just not a big enough sample. this would need to be done thousands of times to be any good.
Coming from the mtb side of things, I like my discs, but tbh, they aren't functionally any better than a good V-brake. Stepping up from cantis to Vs was revelatory; moving from Vs to discs freed up suspension design, and not much else.
PS I weigh 120kg-ish (235lbs), so I think I have more than a little intimate experience with applied braking power. 🤔😂
Si, I absolutely loved this video. It was much more thorough than I have seen from a variety of other videos or articles, and I want to thank you and your GCN staff for their excellent work. I do have a question though. Yes, you covered how many different variables that there could have been for rider weights, rider watts, etc, but what about the likes of aluminum brake track rims (all aluminum or carbon fairing)? They may not be as aero as some of the high end carbon rims, but I've read nothing but praise on how aluminum rims have better overall braking vs their counterparts in carbon. I went down Mt Evans about a week ago with new brake pads and in perfect, clear and dry weather, and I never felt like I couldn't stop safely. Had the conditions changed for the worse (which they did up top when I had reached the bottom), do you think they would have performed better in the wet for confidence and overall capabilities vs the carbon rim wheels? Thanks for your insight and for the staff on an excellent job on this video!
Excellent analysis!
I choose to keep rim brakes. they just perform well, and I like the fact they're reliable and simple to maintain and adjust. I never use my main road/race bike when the wheather is wet, so for me it's a no brainer.
but mine is rubber so it melts time to time -_-
And don't forget, good rim brakes > mechanical discs
go straight for hydro if you want that positive feel
Ive just subscribed, thanks for the video.
I'm seeing a lot of comments about the 'difficult' maintenance of disc brakes.
I changed the brake pads on my commuter for the first time in 18 months last month. Granted, I've been riding the same route for the last 10 years and know the traffic light sequencing and brake points very well, but still, very impressed. Not going back to rims.
Oh, and they were easy-peasy to fit. Yes, a little bit more time but certainly not 'difficult', by any stretch.
Maybe we also need to add hydrologic vs cable disc brakes to the debate too?
I would always prefer hydrologic. I know more complex maintenance, but they won't frost in the winter and you don't need to use as much force while braking
@@pedramPN that's good "hydrologic."
I have Ultegra rim brakes, they work very well when it's dry, just as good as my disc braked mtb but when it gets wet they're almost a joke in comparison.
Taefer
Im a pro mechanic with 50 years riding and racing experience, so heres what I find works really well.
Try ceramic rims. IF you REALLY like your current bike. I like custom built frames and ride them for life. An example are Mavic Open SUP ceramic rims. Probably the only one you can find. An abrasive ceramic coating is added to braking surfaces. Ceramic rims are the best rim braking rims you can buy. They were a thing on high end wheels back in the ‘90s. Not many people had them or knew about them. I still have some. Ive ridden them tens of thousands of miles in nasty dirty conditions, offroading, you name it. They show NO WEAR! With softer abrasive brake pads, such as Koolstop salmons, braking is as effective as discs in the wet conditions.
They are pretty expensive ($100-150 per) and quite hard to find. They are no longer made.
You could also try more aggressive pad compounds like those salmons(Koolstop or Yokozuna) on your present rims. They work well, but wear rims faster. This would be the most cost effective option.
The newer Ultegra direct mount brakes are just as good as discs in dry conditions and pretty good in wet but require a specific frame like discs.
If you ride in wet conditions frequently, discs are the best thing currently. But youll still wear out pads and rotors frequently. Water, dirt, salt, sand and road contaminants are going to do their thing inevitably!!
Most riders (at least where I live) avoid riding in the rain. If thats you, you dont need discs. But the marketing will tell you that you do! They want to sell more stuff and disc brakes require a whole new bike!!
If I was a roadie, (Im not anymore) ‘NEEDED’ a disc brake, and on a budget I might buy just a disc fork and all the other related parts. This mod would not be cheap! The front brake does 70% of stopping and I get pretty attached to my custom steel frames!
I use front mechanical disc and rear v brakes(rear ceramic rim!) on a custom mtb frame and it works great in the worst of conditions. I can repair the brakes on the side of the trail far, far from any civilization on a month long tour. I ride in situations where hydro brakes are not reliable or easy to maintain out in the field.
Another option is to find the HED Jet 5/6 Black wheels which use HED's turbine braking technology to significantly shorten braking distances, especially in the wet. Literally a cross between rim brake and disc in terms of performance. They also sound awesome when braking but no one talks about these. They aren't cheap. Alas, the world has moved one. Now with disc brakes they can easily do wider rim profiles and get better aerodynamics.
He won't let you, due to the risk of the data saying that rim brakes are better ;)
Change for Koolstop salmon pads if you ride on Aluminium rims hudge différence
@@danielhertercasagrande1686 You can also try Darkpads. These pads are excellent !!!
Wow! Great editing
Thanks for the video!
Try riding through really wet muddy patches with rim brakes down a steep descent and see what happens. Rim brakes have more wear and tear including adjusting the cables, swapping out the pads after hard rides, condition of your rims etc.
Hydraulic disc brakes all the way for me as they work in any conditions and require hardly any maintenance.
I would like to see a comparison on the same bike with the two different brakes if possible.
I prefer discs on my MTB. But bleeding them can be a pain. Especially the rear brake. Also they can be very noisy. You don't have to true your wheels but you may have to true the discs from time to time when they start rubbing. So as a mechanic, I would say they can be a lot of work.
wicked. how do you combine all Vid with the same speech.
My next new bike is going to be a disc model. Keep up the great work guys!
I find the limitations of rim brakes most apparent on long, steep, slow, or gravelly descents where I need to do a lot of braking. Fast descents with sweeping corners like the one in the video don't really test brakes very hard. On descents where I have to brake a lot, my rims get very hot which causes my tire pressure to rise well above the recommended limit, and causes my brake pads to lose effectiveness. Sometimes I have to stop and let my rims cool down.
Should get a 250 pound guy and test the brakes out on the descents. Now that's a brake test!!
I'm 220 and not scared. Pick me.
Riding in the rain? Disc brakes. Riding heavy? Disc brakes. Riding light in dry weather, rim brakes are fine.
Disk brakes have their pros and cons. Heat dissipation is one of the cons, especially on hydraulic brakes. Extra strain on forks, frame and wheels? They are still affected by rain (granted, not as much... but that's why you drag you brakes slightly every so often when riding in the wet, no matter what brakes you use) and there's the extra weight. And the higher costs. Cheap discs are no better than a semi decent rim brake.The vast majority of bike riders still have rim brakes, and like most car drivers, they rarely, if ever use their brakes to full capacity.
Nice. Moving away from the maths and data, it was great for Simon to mention that regardless of which brakes you choose, the descent was awesome.
Disk brakes are the future, but I really wish they make the hoods nicer looking.
Having watched many of the GCN video for comparisons, I really wanted this one to be definitive for a better argument on my "feelings". I have to gives prop's to the GCN crew for keeping it scientific and being honest about the findings. With everyone so heated and having opinions, a true scientific comparison was nice to see. Realizing it's about feeling, would it be possible to "race" two riders down together one on disc and one on rim, then switch the riders out. No one wants to crash, but then you might actually see the difference. Just a thought. Again, props for keeping it scientific though. I don't like the answer, but I respect the analysis.
Probably the most sciency science video so far... And you even forgot to put on the science glasses!
Really? Alot of variables(road imperfections,unpredictable headwind, and not following the perfect line of path of the previous one) were involved and he only did that one round per brake type. Science your ass
I've had rim brakes all my life, now I have disc brakes, they rock !
Yes
yes Disc
Bit they weigh two pounds more (heavier hubs, plus flange, plus mounts, heavier fork, disks and heavier calipers.
Is your disc brake hydraulic or mechanical? I wonder if mechanical ones differ too much or slightly from hydraulics.
Hm, inner width 404 NSW rim brake: 17.25mm | inner width 303 disc brake: 21.00mm
So the same tire on the Disc version is wider/has more volume and - as same pressure is used - "harder" and faster on good dry roads but worse in the wet.
This is a really well done video. You guys did a great job. Personally, I say get the HED jet black rims with rim brakes and then you’ll get the braking performance you need in the wet.
I'm keen to see what a high-end disk rim looks like in five years. Am I right to say that not needing a breaking surface or to deal with heat should give more engineering freedom?
Hmmm.... Electronic ABS hub brakes, coaster brakes of the future, and regenerative for those eRoadbikes.
That one of the often overlooked benefits of disks. Freedom in rim profiles. Just look at mtb rims. Plus you can buy expensive carbon rims and know that your not shortening their life every time you brake.
Disc brakes mean that rims are no longer consumable items, so we no longer need to wince as pads wear through expensive wheels. And, now that rims no longer need to function as a braking surface, they can be optimised further in aerodynamics, weight, strength and also tubeless compatability.
Add in to the equation the "fit and forget" aspect, the disc being up out of the way of water and dirt, easier wheel changes, easier truing of the braking surface and better lever feel, it is hard to make a case for rim brakes away from entry level or ultra-light bikes.
always people come with this nonsense of "wearing out rims" - I ride road bike for ~25 years (up to 13000km/year) and didn't have one single rim damaged due to braking in my whole life
fiddler on the bike I guess aluminium rims are more durable than I give them credit for. I assumed they wouldn't be as long lasting as they seem to be because they come with wear guides, and my own experience in working with aluminium has shown it to be relatively soft. Granted, not all aluminium is equal.
Still, carbon rims seem to have a significant failure rate due to heat build up when used as a braking surface. Again this is entirely dependant on the type of riding and the conditions you ride in. Also, I've been led to believe that carbon brake tracks can wear out rather quickly in real world scenarios and if we go down a carbon path, then id hypothesise there will be a significant difference in braking performance when compared to discs.
All things considered, discs are still my preferred option.
if you prefer discs, that is fine; but this wear-out-rims-argument is nonsense. You can only destroy them if you make big mistakes like permanent braking at descends - but if you do so, you are melting discs too (have seen the relicts of those discs...). As I said, I never damaged one single rim with brakes - alu rims until 6/2016, than Campa Bora carbon wheels, ridden ~10000km since than, looks like new). A friend of mine, ex pro rider, uses Lightweight wheels since the 90s and also says he never had an issue with that (and he is riding much more than I)
Howard Davies if you only ride in the dry and keep the rims and pads clean then aluminium rims can last a very long time, but if you do much mileage in the wet, especially if you don't clean them scrupulously, they will wear through. Lighter weight ones have probably lasted about 20000km for me in a lot of wet weather. A good tip is to replace them before they blow apart.
Alloy wheels for me because they are fairly inexpensive to replace and I don't need carbon wheels anyway; I'm no pro and I'm not getting paid to beat anybody to a town sign post. All this disc brake stuff is for the gravel crowd and cyclocross set. Roadies don't Really need them----unless you love riding in the rain/snow.
Hi Simon, that really is proper science - "We did this experiment and realised that we were asking the wrong question from the beginning (but still enjoyed it!)"
such a wonderful landscape my friend..
My commuter has disc brakes and I'll never go back when I'm slogging through traffic whatever the weather. The road bike is still on rim brakes, may well make the move when I buy my next bike but that's a good way off.
Sorry for reply so long after posting - I have a rim braked road bike I commute on mostly (off weekend jaunt). I've been through a number of pads trying to find something that works well in the wet, but with spring and the changeable weather, nothing inspires confidence. In fact the standard old Shimano I've found have the best feel. Are discs a significant improvement? Had you tried expensive (and largely disappointing..) rim pads before? Thank you!
2:41 subtitles
Feel is everything!!! You have what works best for you, where you ride etc.
i am an undecided person so i just installed both for the 2 wheels! Now i have super feeling and super braking power and i never lose brakes!
#torqueback Is there really a need for disk brakes in pairs? New forks could mod most bikes to disk and the font does most of the braking. I remember cars with disks on front and drums on the back. My next bike on budget will be rim brake but I'd love the option to upgrade the forks and front wheel / brakes to disk and leave the caliper on the back.
kierenkd you can easily run disc in front and rim in the back. There was a time when high end XC mountain bikes were set up that way to save weight on the back end and profit from the disc in the front - but people are much more concerned with looks on road bikes and might find that kind of setup revolting 😉
Oh thanks. Thats good to know. I'll keep my eyes peeled on the classified then in case I can see an upgrade on forks - thanks
kierenkd Santana Tandems use V brakes up front and ten inch disks at the back. Their theory is that front brakes are primarily for emergency stops and back are for bleeding speed on long descents . For emergency braking a rim V brake has much more leverage because of greater diameter and eighty percent of emergency stop breaking is on the front wheel and in that situation heat build up isn't a problem. For bleeding speed the ten inch rear brake is used to mitigate against heat build up blowing the tires off the rims.
Hold up Si, if the discs are consistently faster on the straights. That should indicate better Aero performance for discs, not rims.
Side wind when turning corners
It could also be because he's coming out of corners faster because of the added control of discs.
I would also think that he is more comfortable accelerating to a higher speed between corners with confidence that the discs will slow him down sufficiently for the next corner.
He was referring to the more aerodynamic wheels on the rim brake bike. The wheels were not the same.
Hi GCN! The acceleration data can be obtained from your GPS trace. Acceleration is the rate of change of velocity with time. If your GPS trace gives you velocity vs time, the acceleration is (v2 - v1)/(t2-t1) where v2 and v1 are velocities at times t2 and t1 respectively. You could just use Excel to make this calculation with your GPS data. If you have GPS data in terms of velocity vs distance travelled then the acceleration can be found as v1*(v2-v1)/(d2 - d1) where d2 and d1 are distance travelled in place of time. The accuracy of these calculations will depend on how far apart your data points are. Use velocity in units of meters/second (m/s = km-h / 3.6) and you will get acceleration in units of meters/second^2. Divide by 9.8m/s^2 to get the acceleration in units of "G's".
Cornering g-force could also be found from the GPS trace but this might be difficult. I recommend that in the future you calculate acceleration from lean angle. I believe the sensor on the iPhone will work well for this and it will be easy to filter out any high-frequency noise.
If you have any questions, just reply to this comment - I am an engineer and I am happy to help you sort through your data. Great videos on your channel! Keep up the good work!
I would like to know two things: 1st. the disc brakes were hydraulic? and 2nd. (and more important to me) how much easier is it to brake with disc or rim brakes? Thank you!
Law of thermodynamics,
Disc brakes have larger areas to dissipate heat. If you can’t dissipate heat, you can’t slow down. Conservation of energy, the speed must convert to heat or some other loss, otherwise no loss of speed.
Hmm, 622mm of surface area compared to 180mm of surface area. I wonder which one dissipates heat faster? ;-)
But you do have a point, heat from a rim brake gets dissipated in part through the tube/tire and can affect their performance/lifespan and in competition requires the use of nitrogen to prevent overinflation from heat buildup which can lead to a blowout. Disc brake heat gets dissipated in part through the bearings and hub which can affect the performance/lifespan of those components along with the lube which hopefully is heat tolerant. So both have their drawbacks along with any advantages.
Performance aside - Which is more practical? rim or mechanical disk?
The Rim one
love the background music!
You could have better analyzed this by motor-driving a wheel up to a specific speed and then disengaging the drive and with a set amount of contact pressure and a set engagement speed, seeing how long it would take to stop the wheel. If possible selecting similar braking surface contact materials to try to eliminate the differences that can be caused by personal selection.
This was quite interesting but 11:20 made this video great. It's important to mention that when presenting such a "sciencey" topic, so that people are not misled. I think it's a shame you guys couldn't get equivalent rim profiles, but i suppose that also makes a point in favour of the discs that despite superior aerodynamics, it was still close in the dry.
I'd also like to see a run with wheels that have aluminium brake tracks - i certainly imagine there are a great deal of viewers who will probably never buy a set of carbon rims, especially clinchers.
Again, great vid, i really enjoyed the way it was presented. Don't get too full of yourself Si, i'm not talking about that ;)
5:01 is why I think I am done with rim brakes.
@Appu absolutely not true lol
@@HamSupZhai It absolutely is true lol. I have disk breaks on mine and It's quet when it's dry but once it starts to rain... boy the noises disk breaks makes are painful. Also you can true disk breaks all you want but they will still eventually start to rub again. They're just downright annoying af. Already looking for a DI2 + rim breaks option to replace my current one.
@@latte6878 are they new disk pads? because once they're worn in they shouldn't make noises. or your break pads have been contaminated.
@@HamSupZhai I've done about 5000 km on it so far but I live in flatlands so don't need to break that much.
I'll inspect it further to see if the ocasional random rubbing and train horn sounds in the wet can be fixed.
Great video Steve & Dave.
I have a disc braked cx bike and a rim braked rd bike. When I got the rd bike I was pleasantly surprised how good the brakes were.
Whilst they are completely different bikes and component spec what I have noticed is that the discs really come into there own when braking whilst riding on the hoods allowing me to brake harder, with more control than I can with the rim brakes from the hoods