Right, The real reason why tyres are getting wider. It is so they can drop the pressure down to get tubeless to work well, as sealant doesn't work at higher pressures. Manufacturers want to move to tubeless/hookless. To maintain a reasonable aero the wheel needs to be wider to maintain the 105 rule. It really has nothing to do with rolling resistance as it is so small it has very little significant benefit. And it is linear with speed whilst it is squared for aero. Ultimately a tyre rim combination is less aero over 23mm but it is marginal if you maintain the 105 rule, then they can lower the pressure for the same rolling resistance and get tubeless to work more consistently.
@@jeffroom I've been tubeless on my MTB's for 20 years, along with wide rims, disc brakes, and 1x gearing - bikes & gear now far outstrip the stuff I was riding back then. Recently got into road after trying gravel; gravel bikes is also tubeless, disc & 1x. Once I buy new wheels, the s/h road bike I bought as a 'tester' will also be tubeless.
I´d like to see graphs representing rolling resistance, aerodynamic drag and weight as a function of wider tires and wheels. Would be interesting to see if a 30mm really has more pros than cons vs. a 25mm on a climb, flat, slope.
It'd be amazing if we could fit all of that data onto only a few graphs, but there's so many different factors at play that it's almost impossible to do. For example, you can optimise rolling resistance quite easily but only for one specific surface. So if you turn onto a road with slightly smoother or rougher tarmac, all of a sudden you might not be fully optimised. Or as another example, you might be riding a route with one big climb on it, but otherwise either rolling terrain or even flat. Which part of the route do you optimise for? Instead, we have to look at the best all-round option. So whilst it might not be the absolute best possible solution for each individual scenario, we aim for a setup that performs well in as many as possible.
@@ParcoursDov Well you can do a rough, medium and smooth variant of asphalt for rolling resistance, and you can optimize for performance rather than comfort to be specfic. The aero will not be affected by the road and niether will the weight so its not that hard. Then you just focus on lets say flat, 5% gradient and 10% gradient. It wouldnt be hard to put it into a simulation of a known track either. I dont see that you cant put basically all the values I mentioned into just one graph.
@@jleau89 Yeah but you can say that for any cycling tech video. Point of these videos is to nerd out. You can ride your grannys old bike if its just about getting out riding. You dont get progress and development without nerding.
I'm really enjoying this series, even though I've read much of the info. Also the video of the tt bikes is making it very hard for me to not want to buy one.
Love these videos. That engineer/wheel-builder seems brilliant and down to earth all at once. I'm riding on 32mm road tyres (tires) and rims with 21mm internal width, and the combination seems to work pretty durn well: very comfortable, low rolling resistance, decent flat protection, and fast enough for most non-racing purposes. If I were still racing, though, I would not go bigger than 25mm, to be honest. If speed is your only concern, marginal weight and air resistance differences are actually kind of important, and no one gives a damn about your comfort.
fitting calipers around a wheel was never an issue, lol. some road bikes even had v caliper brakes that were integrated with the forks and frame so using them came at little to no aero loss. now compare that to disc...
I want to see the data this is based on. The data I’ve seen suggests that the rolling resistance is nominally the same across a very wide range of tyre widths as long as they’re pumped up to provide the same amount of deflection for a given load.
Yes, that's the conclusion I've seen from many tests. What he said at 0:45 is simply not true. Wider tires do have a lower rolling resistance at the same pressure, but wider tires at lower pressure have exactly the same rolling resistance, and exactly the same comfort. Not more, not less.
@@swe223 A supple tyre has less rolling resistance than a stiff tyre. This is not only due to the reduced hysteric losses but mainly because of the reduced frictional losses in the rider's body. So any test which doesn't involve a rider doesn't test the rolling resistance of the tyre. And yes wider tyres at a lower pressure have less rolling resistance than narrower tyres at higher pressure - up to 25 mm on the smoothest surface and on real roads even up to higher widths. Jan Heine found out that you definitely don't get slowed down on much wider tyres as 42 mm. On gravel above 50 seems to be the optimum as wider tyres don't sink in the surface as much. Every molecule that gets misplaced requires energy.
@@maxsievers8251 there is a very fine line between lower pressure. its very easy to go just too low that the rolling resistance then goes through the roof
@@ezquiel700c I haven't seen data like that. It might be the case with some tyres. Jan Heine found out that there is a broad range of pressure between too low and too high in which rolling resistance doesn't change much. It's more important how supple the tyre is.
Super helpful Francis! I recently got a Trek Domane and it had wider tires. Was considering getting new tires that were skinnier to get better performance. I came to find that I love the comfort of the wider tire, and it good to know that I’m not necessarily giving up performance either. Now I just know that I’m out of shape haha!
A tyre any width can be made softer to give better rolling resistance. The ideal pressure makes a big difference, however a wider wheel and tire excluding tyre pressure with always be slower. So the scientist believe, the bike industry seems to be focusing on one idea to maybe get us to buy new things.
Brilliant explanation from Dov, chapeaux! Francis - great choice in wheel system. I'm also running 30mm Hutchinson TLRs, but on Token G33s - 25 inner with 33 outer. Pressures around 55psi for road - as smooth as butter:)
@@aygwm I normally weigh around 155lb and have found this to be fantastic over the past 3+ years on variable GB roads. Rims have been fine, even with some minor gravel :)
@@stibra101 Possibly true, but I think the gap is narrow. So I chose the TLR system for additional benefits such as self sealing simplicity, price and long tern support/development.
If you are riding perfectly smooth tarmac all the time for relatively short distances, or trying to win a race or a hillclimb competition, then narrow tires might be ok. If not, then 32mm might be the way to go for casual riders. Never underestimate the performance advantage of rider comfort on long distances.
Its not just about rolling resistance, or even aerodynamics, as much as comfort and efficiency over time. Wider tires beat you up less, so you are fresher , especially on rougher terrain. Less bouncing off of pavement imperfections. Conti tubulars @ 180 psi are ok on the boards, but what the pro's have traditionally used in a race like Paris Roubaix, laced aluminum rims with fat silk tubulars, is still the gold standard.
I found that, the sweet spot of tyre width is the one which results the optimal pressure of 4.5-5 bars (with zipp pressure calculator) for the given bike+rider weight.
Wheely interesting, well someone had to say it🙄. I currently run 40c tyres which I use on both road and gravel, have thought of swapping to a narrower tyre but like a bit of comfort. Informative vid, thanks.👍
How can lower pressure give lower rolling resistance? I get way better fuel economy on my motorcycle when I have high pressure in the tires vs low pressure
Would love to see a video about 650b wheels / tyres options for road and gravel. Many manufactures are now putting 650b on smaller sized frames and women specific frames to offer better geometries. Been a long time viewer, love the vids.
Imma just make this clear rim brakes will not kill tire width. Direct mount and other designs can easily clear 30-32mm tires. The design advantage with disc is the lack of brake track.
I think there is an optimal width of roughly 30mm, but past a certain point, tires get too wide and start to slow you down. At that point they cross into the gravel tire sizing.
90s hybrid bikes had it going on and no one knew it. Your 30mm road wheel looks a lot like a old hybrid wheel. I still have a difficult time understanding how fatter tires with lower pressure has less rolling resistance. But I'm fine with it either way because they're more comfortable
a really interesting thought here about how wide a tire you should go. I had to go into the office which is only 4 miles away. I have a Orbea M20 with 28mm tubeless and a Koga Signature with Rohloff, and using Schwalbe Marathon + 34mm tires (double the overall weight). The difference between them was only 5 mins. I found on the Koga I was rolling over the potholes more freely with no concern of loosing control etc.
wait what? as far as i know the lower the tire pressure(or the more it deforms) the higher the grip witch means higher drag? did i not heard something or what? (i ride a mountain bike so i'm that familiar with road bikes)
One thing no one seems to be talking about is that different rim depth most likely have different optimal widths. A 80mm deep TT wheel can be wider than a 40mm wheel to get a airfoil profile. The other factor seems to be not as performance driven as we are told. Aerodynamic performance of a wheel is much more important than rolling resistance and optimizing rolling resistance doesn't make you faster when you give up more in terms of aerodynamics. However, with the rise of tubeless tyres, hookless rims and the use of sealant. Running aerodynamically optimal 23mm tyres on a 40mm rim at 90psi mean hookless rims and sealant do not work properly. I think the optimum for climbing wheels will be 25mm tyres and 28mm for deep areo wheels. Discs we can probably run 30s or 32s.
We might not necessarily be talking about it, but believe me we are thinking about it! A lot of it comes down to exactly how you define "optimal". If you're looking at it purely from an aero perspective, wider is what you're after. But of course with a wider rim, there's more material used, so it comes with a weight penalty. I talked a bit about this with Francis in another of the recent videos but there are certainly times when you want to minimise weight. However, one of the great things about our #thinkwider range of wheels is that you can have both. You can optimise rolling resistance by running a wider (28mm) tyre, but without any aero penalty given the wide rim design. It's definitely a massive topic though and one that we're keen to keep exploring with Francis. If there's a specific part that you'd be interested in hearing about more, just let us know and we'll try to cover it.
@@ParcoursDov How exactly is a 28mm tyre on a 30mm wide rim able to create a more aerodynamic profile than a 23mm tyre on a 25mm wide rim? I'm assuming a shallow climbing wheel with the same depth. There is a 20% increase in frontal area that can't be made up by a more airfoil rim profile the way a very deep (80mm) wheel can make up for it. I'm thinking about width to depth ratio. 30mm 'Lightweight Wheel' ends up with a 1:1 ratio, the 40mm 'Allrounder' has a 1.33:1 ration and the 80mm TT-Wheel has a 2.66:1 ration. I guess there is also the width difference between rim and fork to consider. I think most people understand how the 28mm tyre on the 25mm wide rim is a poor choice. But that is not really my concern. I'm just very doubtful about marketing by the bike industry in regards to marginal gains. Ceramic bearings and 'silly' spin tests come to mind. Some other things about aerodynamics. I personally ride a 6 spoke wheel on my road bike and would love to learn more about spoke impacts on aerodynamics. I especially like the Corima Carbon Spoke design and believe these wheels really punch above their depth because they have 12 spokes instead of the typical 24. What Impact have the disc rotors on aerodynamics? The Shimano Rotors have very different designs compared to the SRAM and Campag Rotors.
@@Circial totally agreed re: the frontal area, but remember that the key element of the drag equation is CdA - so a combination of frontal area (A) with drag coefficient (Cd). Cd is driven by the shape of an object and is dimensionless, so will also have an impact on overall drag. Measuring drag from spokes gets really challenging as you need to consider the rotational drag (i.e. the drag from the spokes rotating with the wheel) as well as the translational drag (i.e. the drag from the spokes moving forwards with the bike and rider). Wind tunnel testing is best suited to measuring translational drag, as for rotational drag you would need to also consider the torque on the axle. Pretty challenging if you're using a motorised rig to spin the wheel to match the airspeed! This is why solid disc wheels are often arguably penalised in a wind tunnel test - by almost removing rotational drag completely they will give a greater aero benefit than the translational drag data can show. Clearly with a deep vs. shallow rim there is also a difference (shorter vs. longer spokes) as well as between a 12-spoke and 24-spoke build. And that's before you begin to consider spoke profiles! As for disc rotors, we've actually tested this. You'll see on our website that we've seen differences of just over 1W between different designs of rotors and around 0.7W between a 140mm and 160mm rotor from the same brand
I have a set of 25mm Inner/32mm Outer width wheels. I’m currently running 28 mm Continental road tires based on the manufacturer’s recommendation. From your discussion I’m wondering if I could go wider. The 28s are nice but I wouldn’t mind a wider tire with lower pressure to dampen the road vibrations of chip seal rural roads in my area. How wide could I go with those wheeldimensions and still get optimum rolling and aero performance? Thanks.
Hi Jerry, hard to say exactly what the ideal setup is without knowing a bit more about the wheels. But from the dimensions you've provided I'd take a guess that you're pretty close to optimal aero performance. However, with our Strade wheelset (which has a similar outer rim width), the drop-off in aero performance between a 28 & 30mm tyre is pretty small. So if you're looking to improve ride comfort, running a 30mm tyre is unlikely to be too detrimental to overall performance.
@@ParcoursDov Thanks, That’s what I hoped to hear. I bought my wheels overseas from Light Bicycles in Shanghai, China last winter. I have both gravel and paved options where I live so I went with the wider 32 mm rims because, I felt they would give me more comfort and tire width flexibility for gravel riding going forward (and because there was a price advantage going wide). But, I have since recognized that the majority of my riding is on pavement and decided to use these wheels as road wheels and use the alloy wheels and 38mm tires that came with the bike for gravel. I originally went with 28mm tires, as I said, based on the Manufacturer’s recommendation, but I think having ridden them the early part of this season that 30s (or maybe even 32s) may be better suited to the crappy chip seal roads around here. I used to ride them on 23 mm tires on 25 mm rims and the difference going to 28s on the 32mm rims is like night and day. The 28s are very comfortable, roll great, and seem to grip the pavement better than any other tires I’ve owned previously. But, that being said, I’m a not very fast recreational rider, so the aero advantages of my wheels are less important to me than their rolling resistance compliance. I want to get any aero advantage I can, of course, but think the vibration damping benefits of the wider tires far out weight any aero benefits of getting the perfect tire/rim profile. I’ll ride the 28s for the rest of this season, but will definitely go a bit larger with my next set of tires. I’m so glad I went with wide rims. Thanks for opening up this discussion.
Excellent, Francis, and surely the industry will have no problem with making aero gravel wheels a thing. And why not, we cyclists do like innovations and new components and perhaps we'll get gravel tires with a golf-ball tread for the win. :)
It's not right for mountain bikes, either. I mean, there is definitely a point at with the narrow part of the lightbulb is too narrow, with a number of detrimental effects.
It was my understanding that at the speeds bicycles travel at the chord length of the wheels is too short to reattach the airflow. Once it's turbulent, it's turbulent.
Just a thought. Is it more likely to get a puncture with a wider tyre opposed to a narrow one? I would assume that if you are touching more of the road surface,there is a bigger chance of hitting a sharp object. Also wider is going to be heavier. I am starting to think that we are being duped into buying the latest trend. It wouldn't surprise me if we went back to super narrow tyres in the future. I know there is a lot of science behind this,but if I have learned one thing in life,it's that science is always changing as we find out more about our world.
Probably negligible, my dad's old GT mountain bike has got 2 inch slicks on it and never got a flat. I think you're right, the industry is trying to get us obsessed with these miniscule gains. But one thing I've noticed since switching to 28s is how my times have improved over long rides, the roads where I live is not perfect and running 28s on lower pressure allowed me to bomb through these rough sections of roads. Really depends on where you live.
@@ILOVEDEFENDINGTHE1PERCENT I have an GT tempest mountain bike also with slicks on it. Come to think of it,I don't ever remember getting a puncture on the road on it either. And I have to admit it is far more comfortable over the crappy roads where I live. I am still old school on the road bike with my 23mm tyres though. Maybe it's my age,but I think they look better,especially on my old steel framed bikes.
@@atmywitsend1984 Most old frames like my Peugeot will only fit 23s unfortunately. Also we tend to attribute things like discomfort, bumpiness and being able to feel the road chatters and vibrations on a rock hard narrow tyre with speed. Some would argue that's the whole point of old school setups, it's about the feeling you get from it more than anything else.
I don’t feel that we were ever restricted to the width of the brake caliper. The width of the rim dictated the width of the caliper. If the rim was made wider a wider caliper would have been close behind. If you build it, they will come, so to speak. Disc brakes had more advantages, so too went the engineering efforts. Another advantage of discs: to not have to redesign the rim, tires, tubes and rim tape width AS WELL AS the caliper.
I think maybe in the video it was not worded so clearly. There is a point where if you want say 30mm+ tyres with rim brakes you have to go with medium drops, 35mm+ say with long drops etc. each time you have a longer drop calliper the worse the braking becomes due to calliper flex and less leverage. Above that point you go to cantis or v-brakes and even then the tyre size is limited to where the brake cable may end up depending on your setup.
@@jonathanip6757 you're absolutely right, I could have been a bit clearer there. The longer version that perhaps is more comprehensive is that we, as an aftermarket wheel manufacturer, were/are constrained by the brake calipers fitted onto our riders' bikes. I'm sure the likes of Shimano, SRAM, Campagnolo, TRP etc. as brake caliper manufacturers have their reasons for the caliper widths they use, but this is what we are restricted to in our rim design.
I feel like I’m in the dark ages running 25mm tubular tyres. 25mm definitely still feels WIDE to me. If I wanted to go wider it’d mean a new bike and possibly new wheels too. Haven’t got a spare 5k to spend on yet another bike.
Great question & it's not just the different depths, but also widths and shapes. The (very) short version of "why" is that we design rims to suit the airflow conditions at different points of the bike, i.e. front wheel & rear wheel. We know from our testing that these are very different, hence the difference in front & rear rims.
@@ILOVEDEFENDINGTHE1PERCENT you're right - the outer width is the driver for aero performance. As I mentioned in the video though, the biggest factor impacting aero performance for gravel will be the tyre. As soon as you introduce the bigger tread patterns on gravel tyres, the negative aero impact will be much, much more than the benefit of a deeper or wider rim
wider tyre + wheel is less aerodynamic than a narrower tyre + wheel. its only faster if can compensate with better rolling resistance. To truly get the best combo you want the external rim width to match the width of the tyre. Tyre choice should be based on road condition and rider weight. A light weigh rider has no reason to go to big 30mm tyre if they can run lower pressure with a 28mm or 25mm tyre. Wider internal rim will impact the real width of the tyre thus also needs to be considered.
I agree, most aero drag penalties would come from a suboptimal position of a rider, clothing, a helmet. That’s where ppl need to seek for optimisations should that be necessary
@@aygwm Yes, they have the latest wheels designed for 28mm tires. Most of us mortals are riding rims designed for 25mm tires...... 28mm on a 25mm rim would create a lightbulb design for the tire which would of course be slower.
@@the.communist Yes you do...you can't compared when you just ride 10km. Those season rider are going at 100km at least every ride. 50km non stop action at minimum 40kmh depends on gradient. Crank arm u have 170mm and 172.5mm. You can also said that 2.5mm make no different. Even a cleat out of position of just 1mm, after 100km ride you'll feel your leg feeling uncomfortable.
never understood 23/25 width tyres, they're uncomfortable and there's so little friction, if it even slightly drizzles you've had it going down an inclination. 32 is the sweetspot IMO
@@reginaldscot165 my guess is that stiff carbon is nowhere near as comfortable as alleged, compared with steel and titanium, so the wider tyres are suddenly necessary where they weren't before, and the science is there to justify it. Disc brakes have been forced on pros and consumers alike, probably to facilitate this trend. Touring bikes always had wider tyres, but they weren't faster. It's almost as if the whole bike industry has decided that everyone, including themselves, was stupid in the old days.
I try using nitrogen to my wheels Francis it's roll smoothly, coz the PSI never change, not like oxygen when temperature got hot it expand? Try it out on your next blog.... Correct me if im wrong.. tnx God bless ❤️❤️❤️
I have a question for Dov. One thing that gets omitted in discussions about tire width is the influence of the rider's weight, (or more properly, system weight). I'm lightweight, and I get on fine with 23 mm tires. It seems to me that ideal tire width should be a factor, (a range of constants allowing for the tire pressure and surface roughness of the pavement), times the square root of the system weight. What does Dov think?
Great point. Looking at it the other way, one of the reasons why increasing inner rim width or introducing hookless rims can be problematic is that it puts an upper limit on tyre pressure. So for heavier riders, they may be forced to either run a wider tyre than their rim is suited to, or a lower pressure than is optimal for them. As an example, a 110kg rider on a hookless wheel with a 23mm inner width / 27mm outer width. According to ETRTO, that's fine to run a 25mm tyre and ensure optimal aero performance, however they would need to run a pressure over the 72.5psi hookless limit or risk bottoming out. Instead they're forced to run something more like a 32mm tyre in order to keep tyre pressure low enough for a hookless system. In doing so, the aero performance goes out the window! In your example, there's still likely to be a benefit from running a wider tyre however. Potentially something to experiment with?
@@ParcoursDov Hi Dov. I didn't explain myself very well. I was thinking of rolling resistance. In my case my system weight is approximately a half that of your 110 kg rider. So for the same tire pressure, my contact patch would have half the area of his. Assuming his contact patch length and width increase uniformly over mine, they'd be 41% longer and wider. Simplistically, for the same tire pressure, that suggests to me that he'd need a 41% wider tire. (I pump my 23 mm rear tire to 100 psi., my preferred pressure.)
@@richardharris8538 I think we're past the limit of my knowledge of tyre mechanics and performance here. What you say does make sense to me, but I also know from discussions with those who have far more tyre knowledge than I do, that (as always with these things) there are multiple factors at play.
@@ParcoursDov Yes, the mechanics of the tire and inner tube are a complication. I'm gonna stick with 23 mm tires at 100 psi, (so long as I don't put on a lot of weight 😀).
3:29 I think someone in other chanel *CN tech ... coff! mention a whole study when you try to be aero is a limit you can co faster as a peak speed but average speed is a whole different game the ave speed of a not pro cyclist for a 100 km won't go slow ... er by using wide tyres, because the weekend warrior rides in average 33 to 36 km hr even if your top speed peak lower your average is quite the same the wattage savings come from the rough seccitions and the gains in your comfort in descent zones ... I really did go deeper on the quite study and decide to try my road rides on my gravel and well now a days the average speed using 40 gravel tyres and 25 is quite close on tarmac.
Even if you don't go with wider wheels/tires.. upgrade your wheels from the stock ones. The difference is astounding. I got vision team 35s and the difference between the stock Axis classic pieces of junk is just mind blowing.
most manufacturers will spec their lower end bikes with very heavy and durable alloy wheelsets to keep costs down and because they will usually last forever. wheels should always be the first upgrade on any bike except for really high end bikes that already come equipped with nice carbon wheels.
I don't buy the width of the caliper argument for determining the width of wheels. Reason being track bikes which have historically had no brakes. Without the limitation of any brake they could have substantially wider wheels yet they have not gone that direction. it's worthy to note that no hour record attempt has ever been done on wide tyres. This suggests that for ultimate performance wider wheels and tyres are perhaps not the way to go. The road surface and comfort being the determining factor in the trend towards wider tyres imho but I'm not convinced by the performance argument as rider weight must also impact what is the sweet spot. A 60kg and 100kg rider will have different needs as such no one size fits all exists. Interesting discussion though.
@@aygwm That's my very point, imho it is not as straight forward to simply state wider wheels and tyres are faster as the marketing blurb does. The environment and rider characteristics such as rider weight determine that. It's all marketing to get people to buy what the industry wants, the same as hookless rim which benefit the industry with ease of manufacture more than benefiting the consumer.
@@aygwm Well you can also pump up wider tires to super high pressures and have similarly low RR, so that's not an argument. They don't do it because it would be less aerodynamic (and heavier but less of an concern on track)
It's not always the case either way.. A wheel can be to narrow, and it can be to wide. Same for pressure, to high or, definitely to low is slower. And disc have nothing to do with wider tires, any modern rim brake can accommodate up to a 30 or 32 wide tire, which wider than a road bike looking for speed is going to be used. Not the same for gravel obviously..
Still not convinced. I ride 25mm tyres at 100psi even though wheels can take up to 32mm (Trek Emonda). The roads here is France are very good and the surface not bad at all. Not convinced to move to even 28mm at say 70-80psi.
a roadesk-endurance bike that fit 30-32 tyres is the absolute best bike i could get. i oftenly need to ride snippets of gravel when on long allday rides, and 30mm tyres make gravel not a pain in the ass. sorry 90s/20s roadbikes. discbrake bikes that fit 28+ is the only way to go from now on. (id own and ride a steel bianchi from 90s, cuz they look the best, dont they?)
If the hub spacing is the same. For sure. Easier to run gravel wheels on xc frame since xc rims are designed for fatter tyres that may not fit your gravel bike frame clearance
Yep, but of course they've changed the "standards" of modern MTBs so the hub spacing is really wide now, my bikes are both "boost" front and rear so I can't run my gravel bike wheels if I wanted to.
Ah yes hub spacing 🤦♂️ more of a rim thing , a gravel specific rim should be fine on an xc bike?, can imagine a gravel bike wheel takes more of a beating if you ride it hard then an xc bike with suspension and bigger tyres
Can someone actually clarify why a wider lower pressure tyre has less rolling resistance please? Because this video doesn’t, it just states that we know it does. (I know why it’s more comfortable or more aero, those are concepts I can understand)
OK, so sooner or later racing tires will be as wide as a classic (I mean 1960-1980s) city bike's wheels (in todays standards 700x32C or 622-32). Nice... You reinvented the wheel, that already existed in almost the same form. You are a genius. And because it is "new technology, designed with science", it will be exceptionally expensive. (Just like the hookless rims more expensive compared to hooked ones, meanwhile cheaper to make).
Rim brakes never were a constraint. Keeping rim and tire width the same does not impact the rim brakes, they just need more spacing. A lot of bs, the reason is rolling resistance, comfort and traction. All because testing shows it makes up for the aero loss. Adding surface area (ie. wider rims/tires) is always less aero.
0:45 Wait, What? wider tires at lower pressure create LESS rolling resistance? I would like to hear the theory and then see the math on that spectacular claim.
I'm sure Dov can elaborate, but generally that is what people are finding when testing. I think there is some argument over tyres being set to the same pressure but not having the same compliance due to higher volume though: www.schwalbetires.com/technology-faq/rolling-resistance/#:~:text=Tires%20with%20a%20smaller%20diameter,roll%20better%20than%20narrower%20tires. conti-tyres.co.uk/latest-news/165-wider-tyres-go-faster www.velonews.com/gear/tech-faq-seriously-wider-tires-have-lower-rolling-resistance-than-their-narrower-brethren/
Why do road bike rims become so wide? Because the industry wants that! Is the same with disc brakes and gravel bikes ! They want money to make even more money and that is the only reason why the cycling world has changed so much! And that's why I stopped cycling after years of cycling! the intrusive nature of the current cycling world just pisses me off!
"We're learning as we go." It's PHYSICS! None of this is new to any well educated engineer. If only the bike industry were as good at physics (not to mention engineering and manufacturing) as it is marketing. Wider wheels do no decrease rolling resistance but they do increase comfort, traction, and aerodynamic drag. So tired of the marketing BS.
Lower pressure will often reduce rolling resistance. Can run more optimum lower pressures in wider tires, so yes, wider tires facilitate lower rolling resistance by allowing lower pressures to be run safely.
The principles are well understood. It's the 'real world' application that's challenging. Trying to find the sweet spot with so much system variability can be difficult when your looking for marginal gains.
@@chbrosz Drag is directly proportional to the [reference] area. Regardless of what reference area you choose, the greater the area the greater the drag. All else being equal, wider wheels have an increased frontal area therefore they have increased drag.
0:45 Says who? If that's faster, how come all the UK hill climb guys and fast TTers are still obsessed with running 20mm track tubs or 23mm clinchers? You can't say the rolling resistance is more on those and that they are less aero. Come on. I'm just not buying it.
The hill climb scene is something of a law unto itself. The idea that removing bolts or racing without bar tape to save a handful of grams is going to be the difference between winning and losing is far more psychological than it is based in hard fact. However, no one is disputing that super-narrow rims and tyres are lighter - there's just less material in them. Whether or not it's faster up a climb will depend on things like the road surface as much as gradient however. Then for time trialling, again it's a slow process of change. We know that a 20mm tub pumped to 140psi _feels_ fast on the road, but plenty of tyre test data suggests otherwise. We are actively testing a range of different rim/tyre combinations to cover both time trialling and triathlon - keep an eye out for the results later in the year.
I find this stuff interesting. Hearing different people speak on it help it make even more better sense to me. If I was a young cyclist, I would grab the slowest tire I could find and then train on it till I could keep up with everyone else, then change out when I go to compete.
Basically it's because of the increasing population and traffic meaning they can't easily resurface and repair roads without major disruption and cost. This means roads are getting rougher and almost dangerous for skinny 20-23mm road tyres! Yes larger tyres at lower pressures roll, stop and corner better on rough roads but skinnier tyres would be faster if they'd resurface the roads more often but that would mean spending money! It's all about money!
Aero sox and shoe cover's will make a bigger difference then the rim's ! I live in Vietnam Aero sox $5.00 Aero Shoe covers $6.00 US D$$ skin suit Less then $60.00 US D, I us $700.00 wheels from china with 7000 miles on them Go fast and keep it cheep
If you don’t race then why not ? A smoother ride and a better experience, not to mention comfortable, while still being able to keep up with your group ride. Why race with a lambo with friends when you can chill inside a mercedes. It’s really up to preference, and then an elitist.
Answer: because you need bigger and bigger tyres with less and less psi so when you lock your “new and improved disc brakes” you dont kill yourself - dont believe the marketing hype rim brakes for life 👊
Right,
The real reason why tyres are getting wider. It is so they can drop the pressure down to get tubeless to work well, as sealant doesn't work at higher pressures. Manufacturers want to move to tubeless/hookless.
To maintain a reasonable aero the wheel needs to be wider to maintain the 105 rule.
It really has nothing to do with rolling resistance as it is so small it has very little significant benefit. And it is linear with speed whilst it is squared for aero.
Ultimately a tyre rim combination is less aero over 23mm but it is marginal if you maintain the 105 rule, then they can lower the pressure for the same rolling resistance and get tubeless to work more consistently.
@@jeffroom I've been tubeless on my MTB's for 20 years, along with wide rims, disc brakes, and 1x gearing - bikes & gear now far outstrip the stuff I was riding back then.
Recently got into road after trying gravel; gravel bikes is also tubeless, disc & 1x.
Once I buy new wheels, the s/h road bike I bought as a 'tester' will also be tubeless.
I´d like to see graphs representing rolling resistance, aerodynamic drag and weight as a function of wider tires and wheels. Would be interesting to see if a 30mm really has more pros than cons vs. a 25mm on a climb, flat, slope.
or you can just ride your bike
It'd be amazing if we could fit all of that data onto only a few graphs, but there's so many different factors at play that it's almost impossible to do. For example, you can optimise rolling resistance quite easily but only for one specific surface. So if you turn onto a road with slightly smoother or rougher tarmac, all of a sudden you might not be fully optimised.
Or as another example, you might be riding a route with one big climb on it, but otherwise either rolling terrain or even flat. Which part of the route do you optimise for?
Instead, we have to look at the best all-round option. So whilst it might not be the absolute best possible solution for each individual scenario, we aim for a setup that performs well in as many as possible.
@@ParcoursDov Well you can do a rough, medium and smooth variant of asphalt for rolling resistance, and you can optimize for performance rather than comfort to be specfic. The aero will not be affected by the road and niether will the weight so its not that hard. Then you just focus on lets say flat, 5% gradient and 10% gradient. It wouldnt be hard to put it into a simulation of a known track either. I dont see that you cant put basically all the values I mentioned into just one graph.
@@jleau89 Yeah but you can say that for any cycling tech video. Point of these videos is to nerd out. You can ride your grannys old bike if its just about getting out riding. You dont get progress and development without nerding.
Time trial bikes use narrow rim and front tyre for obvious reasons l. Usually 23c sometimes 25c.
I'm really enjoying this series, even though I've read much of the info.
Also the video of the tt bikes is making it very hard for me to not want to buy one.
Love these videos. That engineer/wheel-builder seems brilliant and down to earth all at once.
I'm riding on 32mm road tyres (tires) and rims with 21mm internal width, and the combination seems to work pretty durn well: very comfortable, low rolling resistance, decent flat protection, and fast enough for most non-racing purposes. If I were still racing, though, I would not go bigger than 25mm, to be honest. If speed is your only concern, marginal weight and air resistance differences are actually kind of important, and no one gives a damn about your comfort.
Probably one of the more helpful videos I’ve seen on this subject.
fitting calipers around a wheel was never an issue, lol. some road bikes even had v caliper brakes that were integrated with the forks and frame so using them came at little to no aero loss. now compare that to disc...
A perfectly succinct video collection Francis & Dov with the black art of wheel tech & aerodynamics. Maybe a wind tunnel video Francis & Dov? 👌
I want to see the data this is based on.
The data I’ve seen suggests that the rolling resistance is nominally the same across a very wide range of tyre widths as long as they’re pumped up to provide the same amount of deflection for a given load.
Yes, that's the conclusion I've seen from many tests. What he said at 0:45 is simply not true. Wider tires do have a lower rolling resistance at the same pressure, but wider tires at lower pressure have exactly the same rolling resistance, and exactly the same comfort. Not more, not less.
Read Bicycle Quarterly and Jan Heine's book The All-Road Bike Revolution.
@@swe223 A supple tyre has less rolling resistance than a stiff tyre. This is not only due to the reduced hysteric losses but mainly because of the reduced frictional losses in the rider's body. So any test which doesn't involve a rider doesn't test the rolling resistance of the tyre. And yes wider tyres at a lower pressure have less rolling resistance than narrower tyres at higher pressure - up to 25 mm on the smoothest surface and on real roads even up to higher widths.
Jan Heine found out that you definitely don't get slowed down on much wider tyres as 42 mm. On gravel above 50 seems to be the optimum as wider tyres don't sink in the surface as much. Every molecule that gets misplaced requires energy.
@@maxsievers8251 there is a very fine line between lower pressure. its very easy to go just too low that the rolling resistance then goes through the roof
@@ezquiel700c I haven't seen data like that. It might be the case with some tyres. Jan Heine found out that there is a broad range of pressure between too low and too high in which rolling resistance doesn't change much. It's more important how supple the tyre is.
Super helpful Francis! I recently got a Trek Domane and it had wider tires. Was considering getting new tires that were skinnier to get better performance. I came to find that I love the comfort of the wider tire, and it good to know that I’m not necessarily giving up performance either. Now I just know that I’m out of shape haha!
Dude! Love that these tire videos keep coming!!!
A tyre any width can be made softer to give better rolling resistance. The ideal pressure makes a big difference, however a wider wheel and tire excluding tyre pressure with always be slower. So the scientist believe, the bike industry seems to be focusing on one idea to maybe get us to buy new things.
This series of videos has been really great... Simple layman's terms, clear and informative. Thanks a lot!
Brilliant explanation from Dov, chapeaux!
Francis - great choice in wheel system. I'm also running 30mm Hutchinson TLRs, but on Token G33s - 25 inner with 33 outer. Pressures around 55psi for road - as smooth as butter:)
Do you weigh sub 150 lbs? 55 psi is a great way to damage a rim.
You can run 23-25 mm tubulars, same level of comfort, lighter and more aero
@@aygwm I normally weigh around 155lb and have found this to be fantastic over the past 3+ years on variable GB roads. Rims have been fine, even with some minor gravel :)
@@stibra101 Possibly true, but I think the gap is narrow. So I chose the TLR system for additional benefits such as self sealing simplicity, price and long tern support/development.
@@JibbaJabber TLR is so far from simplicity, not made for road.
If you are riding perfectly smooth tarmac all the time for relatively short distances, or trying to win a race or a hillclimb competition, then narrow tires might be ok. If not, then 32mm might be the way to go for casual riders. Never underestimate the performance advantage of rider comfort on long distances.
Its not just about rolling resistance, or even aerodynamics, as much as comfort and efficiency over time. Wider tires beat you up less, so you are fresher , especially on rougher terrain. Less bouncing off of pavement imperfections. Conti tubulars @ 180 psi are ok on the boards, but what the pro's have traditionally used in a race like Paris Roubaix, laced aluminum rims with fat silk tubulars, is still the gold standard.
Brilliant Edits Once Again - Well Done FC
Cheers
I found that, the sweet spot of tyre width is the one which results the optimal pressure of 4.5-5 bars (with zipp pressure calculator) for the given bike+rider weight.
Wheely interesting, well someone had to say it🙄. I currently run 40c tyres which I use on both road and gravel, have thought of swapping to a narrower tyre but like a bit of comfort. Informative vid, thanks.👍
How can lower pressure give lower rolling resistance? I get way better fuel economy on my motorcycle when I have high pressure in the tires vs low pressure
and wider tire is also heavier :) more rubber, so there is also the effect of weight
Would love to see a video about 650b wheels / tyres options for road and gravel. Many manufactures are now putting 650b on smaller sized frames and women specific frames to offer better geometries.
Been a long time viewer, love the vids.
Imma just make this clear rim brakes will not kill tire width. Direct mount and other designs can easily clear 30-32mm tires. The design advantage with disc is the lack of brake track.
on the road, (road racing) 25-28 tires so 28-30mm wide rims, fully rim brake compatable
absolutely no need to go past 28s!
Hi, where i can get same rim and tire?
Ty
I think there is an optimal width of roughly 30mm, but past a certain point, tires get too wide and start to slow you down. At that point they cross into the gravel tire sizing.
Optimal is 60 mm for road :)
90s hybrid bikes had it going on and no one knew it. Your 30mm road wheel looks a lot like a old hybrid wheel.
I still have a difficult time understanding how fatter tires with lower pressure has less rolling resistance. But I'm fine with it either way because they're more comfortable
What was the width of tires used in the Tour de France 100 or so years ago, when roads were no so smooth and were rarely paved?
Going out on a limb here, but I'm guessing those bikes weren't at all optimal.
a really interesting thought here about how wide a tire you should go. I had to go into the office which is only 4 miles away. I have a Orbea M20 with 28mm tubeless and a Koga Signature with Rohloff, and using Schwalbe Marathon + 34mm tires (double the overall weight). The difference between them was only 5 mins. I found on the Koga I was rolling over the potholes more freely with no concern of loosing control etc.
Think tyre compounds and tube type or quantity of tyre sealant makes a larger difference than often discussed.
Yet another great vid 👌🏾✊🏾
wait what? as far as i know the lower the tire pressure(or the more it deforms) the higher the grip witch means higher drag? did i not heard something or what?
(i ride a mountain bike so i'm that familiar with road bikes)
One thing no one seems to be talking about is that different rim depth most likely have different optimal widths. A 80mm deep TT wheel can be wider than a 40mm wheel to get a airfoil profile.
The other factor seems to be not as performance driven as we are told. Aerodynamic performance of a wheel is much more important than rolling resistance and optimizing rolling resistance doesn't make you faster when you give up more in terms of aerodynamics. However, with the rise of tubeless tyres, hookless rims and the use of sealant. Running aerodynamically optimal 23mm tyres on a 40mm rim at 90psi mean hookless rims and sealant do not work properly.
I think the optimum for climbing wheels will be 25mm tyres and 28mm for deep areo wheels. Discs we can probably run 30s or 32s.
We might not necessarily be talking about it, but believe me we are thinking about it! A lot of it comes down to exactly how you define "optimal". If you're looking at it purely from an aero perspective, wider is what you're after. But of course with a wider rim, there's more material used, so it comes with a weight penalty. I talked a bit about this with Francis in another of the recent videos but there are certainly times when you want to minimise weight.
However, one of the great things about our #thinkwider range of wheels is that you can have both. You can optimise rolling resistance by running a wider (28mm) tyre, but without any aero penalty given the wide rim design.
It's definitely a massive topic though and one that we're keen to keep exploring with Francis. If there's a specific part that you'd be interested in hearing about more, just let us know and we'll try to cover it.
@@ParcoursDov How exactly is a 28mm tyre on a 30mm wide rim able to create a more aerodynamic profile than a 23mm tyre on a 25mm wide rim? I'm assuming a shallow climbing wheel with the same depth. There is a 20% increase in frontal area that can't be made up by a more airfoil rim profile the way a very deep (80mm) wheel can make up for it. I'm thinking about width to depth ratio. 30mm 'Lightweight Wheel' ends up with a 1:1 ratio, the 40mm 'Allrounder' has a 1.33:1 ration and the 80mm TT-Wheel has a 2.66:1 ration. I guess there is also the width difference between rim and fork to consider.
I think most people understand how the 28mm tyre on the 25mm wide rim is a poor choice. But that is not really my concern. I'm just very doubtful about marketing by the bike industry in regards to marginal gains. Ceramic bearings and 'silly' spin tests come to mind.
Some other things about aerodynamics. I personally ride a 6 spoke wheel on my road bike and would love to learn more about spoke impacts on aerodynamics. I especially like the Corima Carbon Spoke design and believe these wheels really punch above their depth because they have 12 spokes instead of the typical 24. What Impact have the disc rotors on aerodynamics? The Shimano Rotors have very different designs compared to the SRAM and Campag Rotors.
@@Circial totally agreed re: the frontal area, but remember that the key element of the drag equation is CdA - so a combination of frontal area (A) with drag coefficient (Cd). Cd is driven by the shape of an object and is dimensionless, so will also have an impact on overall drag.
Measuring drag from spokes gets really challenging as you need to consider the rotational drag (i.e. the drag from the spokes rotating with the wheel) as well as the translational drag (i.e. the drag from the spokes moving forwards with the bike and rider). Wind tunnel testing is best suited to measuring translational drag, as for rotational drag you would need to also consider the torque on the axle. Pretty challenging if you're using a motorised rig to spin the wheel to match the airspeed! This is why solid disc wheels are often arguably penalised in a wind tunnel test - by almost removing rotational drag completely they will give a greater aero benefit than the translational drag data can show. Clearly with a deep vs. shallow rim there is also a difference (shorter vs. longer spokes) as well as between a 12-spoke and 24-spoke build. And that's before you begin to consider spoke profiles!
As for disc rotors, we've actually tested this. You'll see on our website that we've seen differences of just over 1W between different designs of rotors and around 0.7W between a 140mm and 160mm rotor from the same brand
Funny. Somehow caliper brakes were the limiting factor? Are roadies against Cantis or bigger calipers or something? That honestly sounds silly lol.
obviously it's beyond all human ingenuity to design a very slightly wider caliper brake!
I have a set of 25mm Inner/32mm Outer width wheels. I’m currently running 28 mm Continental road tires based on the manufacturer’s recommendation. From your discussion I’m wondering if I could go wider. The 28s are nice but I wouldn’t mind a wider tire with lower pressure to dampen the road vibrations of chip seal rural roads in my area. How wide could I go with those wheeldimensions and still get optimum rolling and aero performance? Thanks.
Hi Jerry, hard to say exactly what the ideal setup is without knowing a bit more about the wheels. But from the dimensions you've provided I'd take a guess that you're pretty close to optimal aero performance. However, with our Strade wheelset (which has a similar outer rim width), the drop-off in aero performance between a 28 & 30mm tyre is pretty small. So if you're looking to improve ride comfort, running a 30mm tyre is unlikely to be too detrimental to overall performance.
@@ParcoursDov Thanks, That’s what I hoped to hear. I bought my wheels overseas from Light Bicycles in Shanghai, China last winter. I have both gravel and paved options where I live so I went with the wider 32 mm rims because, I felt they would give me more comfort and tire width flexibility for gravel riding going forward (and because there was a price advantage going wide). But, I have since recognized that the majority of my riding is on pavement and decided to use these wheels as road wheels and use the alloy wheels and 38mm tires that came with the bike for gravel. I originally went with 28mm tires, as I said, based on the Manufacturer’s recommendation, but I think having ridden them the early part of this season that 30s (or maybe even 32s) may be better suited to the crappy chip seal roads around here. I used to ride them on 23 mm tires on 25 mm rims and the difference going to 28s on the 32mm rims is like night and day. The 28s are very comfortable, roll great, and seem to grip the pavement better than any other tires I’ve owned previously. But, that being said, I’m a not very fast recreational rider, so the aero advantages of my wheels are less important to me than their rolling resistance compliance. I want to get any aero advantage I can, of course, but think the vibration damping benefits of the wider tires far out weight any aero benefits of getting the perfect tire/rim profile. I’ll ride the 28s for the rest of this season, but will definitely go a bit larger with my next set of tires. I’m so glad I went with wide rims. Thanks for opening up this discussion.
Excellent, Francis, and surely the industry will have no problem with making aero gravel wheels a thing. And why not, we cyclists do like innovations and new components and perhaps we'll get gravel tires with a golf-ball tread for the win. :)
Lol they already have, Zipp 303s are marketed as gravel wheel as well as for road. I think 48 hunt limitless is as well.
Rule of 60% or something.
@@crimson177 I may even start jogging if they come up with a gravel tri bike.
This has been a great pair of videos… very informative! 😎🍻
Your mate elgin wants more money on his youtube now 🤑🤑🤑🤣
Cycling industry in 10 years: we discovered that narrow tyres and rims are more areo.
How about wheel depth it is also getting higher why so?
As a mountain biker the lightbulb stuff is just what I've always known tyres to look like lol.
It's not right for mountain bikes, either. I mean, there is definitely a point at with the narrow part of the lightbulb is too narrow, with a number of detrimental effects.
I put a set of wider 700c hybrid rims on my old Raleigh and it definitely rides better!
It was my understanding that at the speeds bicycles travel at the chord length of the wheels is too short to reattach the airflow. Once it's turbulent, it's turbulent.
What sort of tyre pressures would you run on a 28 or 30mm tyres?
I also think a bigger volume tyre is better for bigger riders too.
Just a thought. Is it more likely to get a puncture with a wider tyre opposed to a narrow one? I would assume that if you are touching more of the road surface,there is a bigger chance of hitting a sharp object. Also wider is going to be heavier. I am starting to think that we are being duped into buying the latest trend. It wouldn't surprise me if we went back to super narrow tyres in the future. I know there is a lot of science behind this,but if I have learned one thing in life,it's that science is always changing as we find out more about our world.
Probably negligible, my dad's old GT mountain bike has got 2 inch slicks on it and never got a flat. I think you're right, the industry is trying to get us obsessed with these miniscule gains. But one thing I've noticed since switching to 28s is how my times have improved over long rides, the roads where I live is not perfect and running 28s on lower pressure allowed me to bomb through these rough sections of roads. Really depends on where you live.
Wider tyre means less pressure - less likely to push anything through the tyre - who knows 🤔
@@JIMMYHIBBS1 Good point.
@@ILOVEDEFENDINGTHE1PERCENT I have an GT tempest mountain bike also with slicks on it. Come to think of it,I don't ever remember getting a puncture on the road on it either. And I have to admit it is far more comfortable over the crappy roads where I live. I am still old school on the road bike with my 23mm tyres though. Maybe it's my age,but I think they look better,especially on my old steel framed bikes.
@@atmywitsend1984 Most old frames like my Peugeot will only fit 23s unfortunately. Also we tend to attribute things like discomfort, bumpiness and being able to feel the road chatters and vibrations on a rock hard narrow tyre with speed. Some would argue that's the whole point of old school setups, it's about the feeling you get from it more than anything else.
I don’t feel that we were ever restricted to the width of the brake caliper. The width of the rim dictated the width of the caliper. If the rim was made wider a wider caliper would have been close behind. If you build it, they will come, so to speak. Disc brakes had more advantages, so too went the engineering efforts.
Another advantage of discs: to not have to redesign the rim, tires, tubes and rim tape width AS WELL AS the caliper.
I think maybe in the video it was not worded so clearly. There is a point where if you want say 30mm+ tyres with rim brakes you have to go with medium drops, 35mm+ say with long drops etc. each time you have a longer drop calliper the worse the braking becomes due to calliper flex and less leverage. Above that point you go to cantis or v-brakes and even then the tyre size is limited to where the brake cable may end up depending on your setup.
@@jonathanip6757 you're absolutely right, I could have been a bit clearer there.
The longer version that perhaps is more comprehensive is that we, as an aftermarket wheel manufacturer, were/are constrained by the brake calipers fitted onto our riders' bikes. I'm sure the likes of Shimano, SRAM, Campagnolo, TRP etc. as brake caliper manufacturers have their reasons for the caliper widths they use, but this is what we are restricted to in our rim design.
Great insights. Interesting point about aero gravel wheels being "not really a thing". good to know.. but i still like the sex appeal of a deep rim.
I feel like I’m in the dark ages running 25mm tubular tyres. 25mm definitely still feels WIDE to me. If I wanted to go wider it’d mean a new bike and possibly new wheels too. Haven’t got a spare 5k to spend on yet another bike.
Can we have some real world speed gains for going to aero and wider rims e.g. 30kmh ish? Anyone seen any data at this speed?
Hi Francis, what depth wheels are you running, question, why are we seeing different depths of wheels, such as a 39mm front and a 44mm rear. 🚴👍
Great question & it's not just the different depths, but also widths and shapes. The (very) short version of "why" is that we design rims to suit the airflow conditions at different points of the bike, i.e. front wheel & rear wheel. We know from our testing that these are very different, hence the difference in front & rear rims.
Because the roads are getting so worse, especially here in the Uk.
rim should be 105% wider than tires?
I have a 38c gravel tires, does this mean I should get a 40mm inner width rim to go with, to get aero benefits?
I think he meant the outer width.
@@ILOVEDEFENDINGTHE1PERCENT you're right - the outer width is the driver for aero performance.
As I mentioned in the video though, the biggest factor impacting aero performance for gravel will be the tyre. As soon as you introduce the bigger tread patterns on gravel tyres, the negative aero impact will be much, much more than the benefit of a deeper or wider rim
wider tyre + wheel is less aerodynamic than a narrower tyre + wheel. its only faster if can compensate with better rolling resistance. To truly get the best combo you want the external rim width to match the width of the tyre. Tyre choice should be based on road condition and rider weight. A light weigh rider has no reason to go to big 30mm tyre if they can run lower pressure with a 28mm or 25mm tyre. Wider internal rim will impact the real width of the tyre thus also needs to be considered.
Aero is a factor in wider tires. If averaging 21mph and up ---such as a road race, 25mm has proven to be faster that 28mm.
You really think 3mm does make much of any difference at all?
I agree, most aero drag penalties would come from a suboptimal position of a rider, clothing, a helmet. That’s where ppl need to seek for optimisations should that be necessary
I see plenty of pros on 28mm tires. It’s not slowing them down.
@@aygwm Yes, they have the latest wheels designed for 28mm tires. Most of us mortals are riding rims designed for 25mm tires...... 28mm on a 25mm rim would create a lightbulb design for the tire which would of course be slower.
@@the.communist Yes you do...you can't compared when you just ride 10km. Those season rider are going at 100km at least every ride. 50km non stop action at minimum 40kmh depends on gradient. Crank arm u have 170mm and 172.5mm. You can also said that 2.5mm make no different. Even a cleat out of position of just 1mm, after 100km ride you'll feel your leg feeling uncomfortable.
The best type of tread for gravel is smooth. Ted King rides smooth tyres in his gravel races. Only in mud, snow and wet sand you profit from knobs.
never understood 23/25 width tyres, they're uncomfortable and there's so little friction, if it even slightly drizzles you've had it going down an inclination. 32 is the sweetspot IMO
Its for speed. 23 vs 32 is almost 1 cm. Noticeable maybe. But 23 vs 25 is a joke
30mm is the sweet spot.
Er, so how did pro riders descend high mountains at 60 mp/h for 50 years, using rim brakes, without crashing any more than they do now?!
@@reginaldscot165 my guess is that stiff carbon is nowhere near as comfortable as alleged, compared with steel and titanium, so the wider tyres are suddenly necessary where they weren't before, and the science is there to justify it. Disc brakes have been forced on pros and consumers alike, probably to facilitate this trend. Touring bikes always had wider tyres, but they weren't faster. It's almost as if the whole bike industry has decided that everyone, including themselves, was stupid in the old days.
What PSI do you run on a 28-32 tire?
I try using nitrogen to my wheels Francis it's roll smoothly, coz the PSI never change, not like oxygen when temperature got hot it expand? Try it out on your next blog.... Correct me if im wrong.. tnx God bless ❤️❤️❤️
I have a question for Dov. One thing that gets omitted in discussions about tire width is the influence of the rider's weight, (or more properly, system weight). I'm lightweight, and I get on fine with 23 mm tires. It seems to me that ideal tire width should be a factor, (a range of constants allowing for the tire pressure and surface roughness of the pavement), times the square root of the system weight. What does Dov think?
Great point. Looking at it the other way, one of the reasons why increasing inner rim width or introducing hookless rims can be problematic is that it puts an upper limit on tyre pressure. So for heavier riders, they may be forced to either run a wider tyre than their rim is suited to, or a lower pressure than is optimal for them.
As an example, a 110kg rider on a hookless wheel with a 23mm inner width / 27mm outer width. According to ETRTO, that's fine to run a 25mm tyre and ensure optimal aero performance, however they would need to run a pressure over the 72.5psi hookless limit or risk bottoming out. Instead they're forced to run something more like a 32mm tyre in order to keep tyre pressure low enough for a hookless system. In doing so, the aero performance goes out the window!
In your example, there's still likely to be a benefit from running a wider tyre however. Potentially something to experiment with?
@@ParcoursDov Hi Dov. I didn't explain myself very well. I was thinking of rolling resistance. In my case my system weight is approximately a half that of your 110 kg rider. So for the same tire pressure, my contact patch would have half the area of his. Assuming his contact patch length and width increase uniformly over mine, they'd be 41% longer and wider. Simplistically, for the same tire pressure, that suggests to me that he'd need a 41% wider tire. (I pump my 23 mm rear tire to 100 psi., my preferred pressure.)
@@richardharris8538 I think we're past the limit of my knowledge of tyre mechanics and performance here. What you say does make sense to me, but I also know from discussions with those who have far more tyre knowledge than I do, that (as always with these things) there are multiple factors at play.
@@ParcoursDov Yes, the mechanics of the tire and inner tube are a complication. I'm gonna stick with 23 mm tires at 100 psi, (so long as I don't put on a lot of weight 😀).
3:29 I think someone in other chanel *CN tech ... coff! mention a whole study when you try to be aero is a limit you can co faster as a peak speed but average speed is a whole different game the ave speed of a not pro cyclist for a 100 km won't go slow ... er by using wide tyres, because the weekend warrior rides in average 33 to 36 km hr even if your top speed peak lower your average is quite the same the wattage savings come from the rough seccitions and the gains in your comfort in descent zones ... I really did go deeper on the quite study and decide to try my road rides on my gravel and well now a days the average speed using 40 gravel tyres and 25 is quite close on tarmac.
Even if you don't go with wider wheels/tires.. upgrade your wheels from the stock ones. The difference is astounding. I got vision team 35s and the difference between the stock Axis classic pieces of junk is just mind blowing.
most manufacturers will spec their lower end bikes with very heavy and durable alloy wheelsets to keep costs down and because they will usually last forever. wheels should always be the first upgrade on any bike except for really high end bikes that already come equipped with nice carbon wheels.
@@adrianc6534 in my casey axis wheels definitely did NOT last forever. I was having to true them constantly. Horrible things.
I don't buy the width of the caliper argument for determining the width of wheels. Reason being track bikes which have historically had no brakes.
Without the limitation of any brake they could have substantially wider wheels yet they have not gone that direction. it's worthy to note that no hour record attempt has ever been done on wide tyres.
This suggests that for ultimate performance wider wheels and tyres are perhaps not the way to go.
The road surface and comfort being the determining factor in the trend towards wider tyres imho but I'm not convinced by the performance argument as rider weight must also impact what is the sweet spot.
A 60kg and 100kg rider will have different needs as such no one size fits all exists.
Interesting discussion though.
Tour De France riders use 25mm tyres........if 30mm was faster you would think they would use them......
They’re riding on a perfectly flat, hard surface, a track. So they can pump up to super high pressures and rolling resistance is less of a factor.
@@aygwm That's my very point, imho it is not as straight forward to simply state wider wheels and tyres are faster as the marketing blurb does.
The environment and rider characteristics such as rider weight determine that.
It's all marketing to get people to buy what the industry wants, the same as hookless rim which benefit the industry with ease of manufacture more than benefiting the consumer.
@@aygwm Well you can also pump up wider tires to super high pressures and have similarly low RR, so that's not an argument.
They don't do it because it would be less aerodynamic (and heavier but less of an concern on track)
1:11 Could've been elements to 'factor' in
It's not always the case either way.. A wheel can be to narrow, and it can be to wide. Same for pressure, to high or, definitely to low is slower. And disc have nothing to do with wider tires, any modern rim brake can accommodate up to a 30 or 32 wide tire, which wider than a road bike looking for speed is going to be used. Not the same for gravel obviously..
Still not convinced. I ride 25mm tyres at 100psi even though wheels can take up to 32mm (Trek Emonda). The roads here is France are very good and the surface not bad at all. Not convinced to move to even 28mm at say 70-80psi.
You will just gain comfort n grip.
this made me miss james and bike fit tuesday
The weight weenies won’t go for 32mm tyres, and they might have a point if you ride in a hilly area 🤔
Might? Id say its a definite
Thanks Francis...my next upgrade will be wheels....Peace
Tour De France riders seem to go for 25mm tyres........Why not 30mm??? 😀😀😀😀
.....to make disc brakes less lethal (lost traction on narrow tyre) 😆
whoa breaking news! you should sell this info to pro's who still pick rim brakes
a roadesk-endurance bike that fit 30-32 tyres is the absolute best bike i could get. i oftenly need to ride snippets of gravel when on long allday rides, and 30mm tyres make gravel not a pain in the ass.
sorry 90s/20s roadbikes. discbrake bikes that fit 28+ is the only way to go from now on.
(id own and ride a steel bianchi from 90s, cuz they look the best, dont they?)
Disc bikes are a pain with their zinc, zinc, zinc.......
how old are you cade?
Richie from Melbourne.
Buen video, dan ganas de comprar unas ruedas
I always wonder the difference between a gravel wheelsets and a xc wheelset , can you run gravel on xc and xc on gravel? 🤷♂️
If the hub spacing is the same. For sure. Easier to run gravel wheels on xc frame since xc rims are designed for fatter tyres that may not fit your gravel bike frame clearance
Yep, but of course they've changed the "standards" of modern MTBs so the hub spacing is really wide now, my bikes are both "boost" front and rear so I can't run my gravel bike wheels if I wanted to.
Ah yes hub spacing 🤦♂️ more of a rim thing , a gravel specific rim should be fine on an xc bike?, can imagine a gravel bike wheel takes more of a beating if you ride it hard then an xc bike with suspension and bigger tyres
Can someone actually clarify why a wider lower pressure tyre has less rolling resistance please?
Because this video doesn’t, it just states that we know it does.
(I know why it’s more comfortable or more aero, those are concepts I can understand)
OK, so sooner or later racing tires will be as wide as a classic (I mean 1960-1980s) city bike's wheels (in todays standards 700x32C or 622-32). Nice... You reinvented the wheel, that already existed in almost the same form. You are a genius. And because it is "new technology, designed with science", it will be exceptionally expensive. (Just like the hookless rims more expensive compared to hooked ones, meanwhile cheaper to make).
Rim brakes never were a constraint. Keeping rim and tire width the same does not impact the rim brakes, they just need more spacing. A lot of bs, the reason is rolling resistance, comfort and traction. All because testing shows it makes up for the aero loss. Adding surface area (ie. wider rims/tires) is always less aero.
0:45 Wait, What? wider tires at lower pressure create LESS rolling resistance? I would like to hear the theory and then see the math on that spectacular claim.
I'm sure Dov can elaborate, but generally that is what people are finding when testing.
I think there is some argument over tyres being set to the same pressure but not having the same compliance due to higher volume though:
www.schwalbetires.com/technology-faq/rolling-resistance/#:~:text=Tires%20with%20a%20smaller%20diameter,roll%20better%20than%20narrower%20tires.
conti-tyres.co.uk/latest-news/165-wider-tyres-go-faster
www.velonews.com/gear/tech-faq-seriously-wider-tires-have-lower-rolling-resistance-than-their-narrower-brethren/
Why do road bike rims become so wide? Because the industry wants that! Is the same with disc brakes and gravel bikes ! They want money to make even more money and that is the only reason why the cycling world has changed so much! And that's why I stopped cycling after years of cycling! the intrusive nature of the current cycling world just pisses me off!
Basically bad road surfaces need wider tyres to roll faster, wider tyres need wider rims.... It's a vicious cycle.....
"We're learning as we go." It's PHYSICS! None of this is new to any well educated engineer. If only the bike industry were as good at physics (not to mention engineering and manufacturing) as it is marketing. Wider wheels do no decrease rolling resistance but they do increase comfort, traction, and aerodynamic drag. So tired of the marketing BS.
Lower pressure will often reduce rolling resistance. Can run more optimum lower pressures in wider tires, so yes, wider tires facilitate lower rolling resistance by allowing lower pressures to be run safely.
The principles are well understood. It's the 'real world' application that's challenging. Trying to find the sweet spot with so much system variability can be difficult when your looking for marginal gains.
Also, wider wheels increase the frontal area, yes, but can in turn dramatically reduce the Cd, and thus significantly reduce drag.
Do your own research, there are many resources available. Or feel free to repeat the bike marketing drivel here.
@@chbrosz Drag is directly proportional to the [reference] area. Regardless of what reference area you choose, the greater the area the greater the drag. All else being equal, wider wheels have an increased frontal area therefore they have increased drag.
The question is why did people ever ride 23's
I was a mechanic in the late 1990’s and it was always a question of whether you wanted 700c x23 or if you were hardcore and went with 19’s lol
I guess people assumed thinner = less friction therefore faster 🤷
There was a time when 23's were considered 'Wide''! 😀
My 2009 Felt frame can't fit wider tires than 23's 😬
I still ride 23c on the front and 25c on the back.
Last 🛞
Hi Francis
hello!
but how about wider riders? 🤔💪
Wider riders, more wind drag, slower results.
@@the.communist it was a joke but OK
@@the.communist It would also increase the space between the ears;)
Tfw you daily a 23 in London
30MM 😎
0:45 Says who? If that's faster, how come all the UK hill climb guys and fast TTers are still obsessed with running 20mm track tubs or 23mm clinchers? You can't say the rolling resistance is more on those and that they are less aero. Come on. I'm just not buying it.
The hill climb scene is something of a law unto itself. The idea that removing bolts or racing without bar tape to save a handful of grams is going to be the difference between winning and losing is far more psychological than it is based in hard fact. However, no one is disputing that super-narrow rims and tyres are lighter - there's just less material in them. Whether or not it's faster up a climb will depend on things like the road surface as much as gradient however.
Then for time trialling, again it's a slow process of change. We know that a 20mm tub pumped to 140psi _feels_ fast on the road, but plenty of tyre test data suggests otherwise. We are actively testing a range of different rim/tyre combinations to cover both time trialling and triathlon - keep an eye out for the results later in the year.
I find this stuff interesting. Hearing different people speak on it help it make even more better sense to me.
If I was a young cyclist, I would grab the slowest tire I could find and then train on it till I could keep up with everyone else, then change out when I go to compete.
I hear a tyre inside a tyre is the way to go 👀
@@Cade_Media I saw that video. Totally a training tire.
Basically it's because of the increasing population and traffic meaning they can't easily resurface and repair roads without major disruption and cost. This means roads are getting rougher and almost dangerous for skinny 20-23mm road tyres! Yes larger tyres at lower pressures roll, stop and corner better on rough roads but skinnier tyres would be faster if they'd resurface the roads more often but that would mean spending money! It's all about money!
The reason with wider tires are because of the disc brakes problem. That's all.
Great, ANOTHER standard is changing. This sport kills me man.
AND....good luck at Unbound.....
Why not put MTB wheels and 60 mm tires, that is the fastest :)
Aero sox and shoe cover's will make a bigger difference then the rim's ! I live in Vietnam Aero sox $5.00 Aero Shoe covers $6.00 US D$$ skin suit Less then $60.00 US D, I us $700.00 wheels from china with 7000 miles on them Go fast and keep it cheep
Ffs, I'm still on 25's. LOL
If you don’t race then why not ? A smoother ride and a better experience, not to mention comfortable, while still being able to keep up with your group ride. Why race with a lambo with friends when you can chill inside a mercedes. It’s really up to preference, and then an elitist.
Answer: because you need bigger and bigger tyres with less and less psi so when you lock your “new and improved disc brakes” you dont kill yourself - dont believe the marketing hype rim brakes for life 👊
Rims4theWin
Why the USA flag at your background?
#GoodStuff