@@DR_1_1 not possible to be so accurate. You would need a lab-grade test setup for that. And your position on the bike would have much more influence (on the end-time), even if you put out the same power to the watt. But this is not meant as a scientific measurement.
I’m limited to 25c on my updated Colnago C50. I wish I could go up to 28 but I can’t. I use 28 (which inflate to 29/30mm actually) on my other, more recent bikes
definly the worst part of old bikes. i aint sweatin' disc brakes or aero integration or electrics. i just wanna fit bigger tires as it's proven to be both faster and more comfy.
@user-if1gh4xl5h same. My poor bike sweats every time I watch one of these videos showing how going from 28-30 is a performance increase seeing as it doesn't have the clearance for 25s 😂😅. New bike coming as soon as I get the money
Your right on , I put 25c tyres on my new wheelset , Pro Lite Garda , those rims are wider than an older rim , tyres are 27 mm wide now ? Makes a huge difference on rim width ....A 32 on my new wheels would be 34 wide etc
It would be interesting to see the Strava segment "compare" view of the different runs/sizes given the varying terrain of the course. In other words, did the wider tires gain their time steadily throughout the course or were they significantly faster in certain sections and potentially slower in others, etc. Might shed some additional light on their strengths.
Yeah, we looked at that. The results seemed consistent throughout the course, with no definite places where one tire size was gaining or losing time (Similar to our cheap vs expensive tire testing video: th-cam.com/video/6x1uROsxBNk/w-d-xo.html ) Granted, GPS Data can be inconsistent which is why we were looking at lapped time comparisons.
It's amazing ! I remember a well known very experienced " Cyclo tourist "was engaged in a conversation with an equally well known "Bike Racer "in my local bike shop ! This is in the early 1980's ! The Cyclo tourist said the TDF pros should use lower gears and wider tyres ! All the racers in the shop were laughing at him ! Look at the TDF peloton today ! I have an ancient Steel Racing Bike and love my 23 tyres and my 52/42 6 speed freewheel ! There you go !
Been riding with 32's since 2016 love them once you are rolling around 29 30 mph the bike feels like it's floating and the tires make a humming sound, love it.
Two years ago I changed 25 for 28, because I wanted more comfort, but I was dead sure that I would loose on speed. Quite lately I learned something about pressure (never used calculators), turned out I pumped way too much..I compare myself riding 25c with 105-110psi two years ago with the present 28c and 70-75 psi and these are two different worlds in terms of comfort and stability. And now I learn that on top of that I have actually a faster bike! Amazing
The difference between the 32s and 34s is well within the margin of error. I ride 35 gravel king slicks for road riding on my gravel bike. I don’t see much of a difference between these and the 28mm Conti 5000 on my second set of wheels. Larger is less rolling resistance but if you you get too large the weight and aerodynamic penalty will set in. The question is, How large is that. For a recreational rider, I think comfort is king. At the end of the day you’ll be happier!😊
I’m a recreational rider. I’ve got a lovely ti road bike I managed to get 28/30s into, but I never use it, I just use my gravel bike with slick 650/47s on light 24mm ID MTB rims on the road all year. The roads are so crappy and broken especially in winter that they’re perfect, don’t puncture, and grip really well on cornering, so downhill they’re actually faster, plus in the summer I can go down any trails I like the look of while I’m out. They aren’t aero, but neither am I!😅
In this test the 28s are too high pressure wise, the drop from the 28 to the 32 is huge compared to the 32- 34mm (31 and 33mm actual). If that is what Silca calc is stating for these lightweight riders then on that broken surface the 75/73psi is far too much and the results are not comparable. If the take 10psi out of the 28mm tyre then we'd have a proper comparison and suspect the 28mm would be same or better.
Jeff I love all the race recaps and Alviso videos, but I really love seeing these science-based videos. You inspire me a lot and I’ve always been a fan since I first learned about you, keep up all the great work and thanks for the videos!
It's refreshing to see roadies with an open mind who can do some basic testing without letting their bias completely screw up the results. Thanks for the video.
I think inner width and outer width of the rim will determine which tire is the fastest. That set of roval wheels I heard test really well with wider tires. BTW, you should also test, wider rear tires than front tires. Peaktorque says rear tire width does not matter for areodynamics.
In addition the tire clearance of the bike also makes a huge difference. On bikes with 45mm clearance, a 40mm tire would be optimal, whereas a bike with 32mm clearance, I think a 30 or 28mm tire would be optimal. Then there is the design of the bike. 3T, for example, has the same clearance for their Exploro Racemax model and their Exploro Ultra model. The Racemax model is optimised for smaller tires and the Ultra of course for larger tires.
It's cool to see the results are very similar on both tests. This is probably one of the most useful comparison videos I've seen you do, simply because most people can afford almost any tire. Awesome video!
NO BS, spot on, I love you guys! That's just what I want to do but without the time and resource! Plus there might be another plus for bigger tyres, there's no strong evidence, just my own feeling, that the bigger tyres feels a lot more grippier in the corner than slimmer ones. If that is true, then bigger tyres would have another plus for maybe more cornering speed, which could translates to faster descent or less race time for some guys, or a more stable "safer" downhill feeling for other less racey guys. Hope you guys could do some experiment with this. It will be interesting to see if this is really a thing.
Guessing that the aero profile of the wheel is greatly affected by the time you get to 34s. But again, in a crit race that'd probably be insignificant. Good test guys!
It depends on the rim/tire interface. On some tire and rim combos 32s are faster than 28s (aerodynamically). On other configurations the 28s will be faster. Peak Torque did a video about this a while back. But for my riding, I prefer the cornering, braking and comfort of wider tires, sacrificing tiny bit in weight and aerodynamics.
inner rim width might help a lot with that. I have a road bike with 17mm inner width and another one with 23mm inner rim width and it's totally different how it affects the shape of the tyre
Yes, in essence PeakTorque found that the aero advantage of a deep section wheel was quickly lost once the tyre width exceeded the external width of the rims... a near flat profile being ideal. And as mentioned, a smooth transition between tyre and rim would also be very helpful, though that would normally require you to run hookless rims. I may be wrong, but I think we've got a set of Winspace Hypers on one bike (28.5mm ext) and similar Rovals... CLXII?? (30mm ext) on the other. The Winspace taper down towards the tyre a little, and are thereby *aerodynamically* optimised for a narrower tyre.... likely a 25c. I think the Rovals have a flatter profile and probably assume a 28c. BUT as this test shows, the wheel manufacturers need to be looking at optimising for 32c.... maybe even more! I also wonder if there's a substantial aero penalty from using Corsas, which have quite substantial and continuous grooves as tred. I'd bet that Contis and Goodyears would cut the air better, and maybe even grip as well given the lower pressures being run.
In case this helps a newer rider: I’ve only been riding for about 18 months. I switched from lower quality 25s to good 28s and the difference was clear as day.
Hi, thank you for the video. It is an interesting comparaison. Maybe the rim width could influence the result and the couple rim width+tire width is to taken in account to have the best and coherent aerodynamism. Another factor could be the elevation of the ride, during a long climb with a slower speed, the weight could change the game in favor of 28mm. But thank for this work that could help everyone to undestand the best option !
Seems like it has been like 3 years or so where we've jumped from calling 25mm tires wide but maybe not so fast to having to decide between various 30+ mm sizes which are both more comfy and faster. Love cycling. P.s. this is an awesome test. Short, concise, no BS. Keep it up. P.p.s I'll be ordering 30mm gp5000 for my sl7 to replace the 26mm turbos.
Great test guys and the results don’t surprise me all that much. I own a gravel bike with 40 mm tyres and while it is slower than my road bike with 28mm it’s not as big a difference in pure speed as you would expect and it’s so much more comfortable.
Plus one to this comment! I'm in exactly the same boat. I do the same loops in about the same times on my gravel bike on 40mm gravel slicks. But gee, it's kinder on my bones!
Sooo awesome, I want to go wider but the debate in my head is killing meee. Thank you guys for this awesome test. I’m buying 32’s thanks again. Keep it up
@@NorCalCycling Exactly, for the nerds like me out there, for every increase of 4mm of internal rim width, it is like going up 1 tire size. A 21mm internal rim width wheel with a 30c tire will be the same as running a 25mm internal width rim on a 28c tire. Sure there will be tiny differences in contact patches and comfort due to the way the tire will stretch and shape itself on the rim, but they will measure out the same final width.
I put 32 Mondo’s on for winter riding. They measured 31 when I first put them on, but now measure 34 on my Alpinist wheel set after about 1000 miles of riding. While a smidge heavier, I don’t feel slower, and the comfort of rough desert roads is much better.
This sort of goes with what sram and zipp have stated in the past about vibration loses and that many 10s of watts can be found using wider tiers or other devices that can soak up vibration. There certainly is a trade off between aero and this but we saw many tour riders running shallower wheels with wide tiers this year. It would great to see of shallower wheels with wider tiers make an even bigger difference to what you found here.
For the the effort here, the algo and my envy my old Trek 5200 can't see these optimal sizes. Great work guys: direct, analytical and super work. Subscribed
Would love to see this comparison up hill. Rotational weight is 3X actual at the furthest distance from the hub. With the additional mass of a larger tire+wider/deeper rim, I find them slower to accelerate and more difficult to maintain speed while climbing. 25mm handmade clinchers(Veloflex, Challenge, Vittoria, Dugast, FMB) still feel the fastest and plenty comfortable. Please include them in a climbing comparison.
Average on Tour de France is 25-26 mm. Might have been less a decade(s) ago, although in older times like 100 years ago maybe, they had very big tyres at some point (and very bad roads!)... For recreational road biking 28 mm feels like a good compromise to me, maybe slightly more if you are a "big guy".
@@dirtangry No, in 2023 average was 25-26 mm. Vandegaard won stages with 24 mm, Pogacar had 30-32 mm on several occasions, they use a lot of different gear, anyway, so it's difficult to keep track and make exact statistics.
Great video! It would also be interesting to do a test on mixed tire sizes. I saw in a bike check video that some pros had narrower tires up front, and wider in the rear. Either for better aerodynamics and comfort, or to trick their opponents.
Great video, your results don't disagree with some similar tests by GCN and others. As a point of history from a now old guy racing crits/track in the 90s, Conti used to make 18mm tires with a sidewall rating of 150PSI which I ran regularly up to 170PSI on the road. I worked in a shop too and it was believed by nearly all racers that skinnier and harder tires were faster, no one was discussing hysteresis and I believed it too. But, even then we knew these skinny hard tires were not so great in the turns of a crit and my crit tire setup was to run a fat at the time front 23-25mm and a skinnier rear around 20mm, again thinking the 20mm=lower rolling resistance, both tubular. I think it's great that today's cyclists have access to so much scientific facts and data to support current trends in gear, nutrition, training, etc.. I only wish we had power meters and a strava to record back in the 90s; I raced as high as CAT 1 on the track, 3 on the road and I have no idea how fast or fit I really was.
Remember when VREDESTEIN started to be imported to the US in the late 90s? We couldn't believe that a clincher could go up to 170psi! (Not that it was needed). 115-120 was good enough. I still have a stash of Vredestein fortezza 23mm in the back of my closet away from sunlight...with a steel Colnago Master.
Quality content!!!! This is data even the average rider can use. Thanks a bunch. The race videos are fun but the real world testing is what brings me back again and again.
There was a time when MTB tires got wider and wider (up to 3"). They have come back to 2.3" to 2.4" which appears to be the sweet spot. Likewise, widths for road tires could overshoot in the coming years (perhaps 35-38mm) and eventually come back to a more reasonable width of 28-32 mm.
It depends on the bike it depends on the terrain. If you ride glass smooth roads all the time then yes 28, 32 would be ideal. If you ride the real roads, as in Most states with crumbling infrastructure than 34, 35 even 38 may be better performing under rough conditions.
Matching the profile of your rim is going to give you the fastest times unless the roads are terrible. You can see in the face-on images that the 32mm tire best matches up with the rim profile for this test which is why it was the fastest and why it was a bigger advantage for Will as aerodynamics became a bigger factor at the higher speed.
For crits especially. 32s and 34s have more contact patch which could increase your cornering speed or at least help the bike feel more stable when leaned way over in a corner.
@paxundpeace9970 i switched 23mm with 2.0" and had the same top speed during the descent. I was far more confident during cornering on the wider tyre though.
I know this isn’t ideal for testing, but would be interesting to see this same test but on tubeless. I think you’ll see those 32’s actually measuring out at the correct size as your test confirmed 30’s is the best setup😅
@@joneaton3366 do some experimenting on the same wheel set and you’ll be able to measure the difference when it’s only air filling up the volume of the tire vs an internal tube.
insanity,thanks for the great video guys.I am running 28mm back(max fitting size),30mm front now. went from 25mm to 30mm front,the ride got much smoother
What year is your Cervelo, ? I ride a 2013 R3 and still on 23's! After watching this video I am wondering how wide I can go, I am quite sure I can run 25, and maybe 28 in the rear, but definitely cannot run 28 in the front, Is there a noticeable difference from 23 to 25? Some of the guys I ride with, who ride newer bikes are riding on 28's, they really like them
@@philring7681 I'm on a 2011 S2. I can get a 25 Vittoria corsa on, but there's no way it could handle something bigger. I don't notice much of a difference, but I've only recently started keeping pressure of clinchers under 90. I'm sure 28+ would be noticable, but a new bike isn't in the cards for a while. Going to switch to latex this summer. Good luck
I use to be a bike mechanic. I love everything on wheels and I must say, the road cycling world may be the most stubborn, slow thinking, low evolution industry I know of. Seems like most tech advances were made from the MTB world or other industries (cars, planes...). I was sure that 28mm tires would be better than 25mm 15 years ago. 32mm starts to become heavy for acceleration with these 65kg riders. The way the mentality changed when Peter Sagan started to win shows the rigidity of the mindset in road cycling. NorCal you're awesome, love your channel and don't take it personally please.
That's true but the bulge from 25 to 28 on regular double wall rims is acceptable for casual riders who could have benefit from a much comfier, safer and faster ride for many years nonetheless. Also lacing a road hub onto an MTB rim is no sorcery than many could have tested.@@l.d.t.6327
@@l.d.t.6327meanwhile mtb comes with 35mm internal width rims, and they’re still faster, and more comfortable. We haven’t come close to the limit on road bikes yet still
I'm glad you used the Silca calculator and actually meadured the width. My Pirelli 28 tires are nearly 30 on my Elite 50D rims. Also, you made an important point, fatter feels slower but isn't. Once these are worn out I guess I'll buy 30s.
Jeff, your video made me look into getting 32mm tires. Googling the Roval wheelset you used in the test showed a front wheel width of 35 mm and rear wheel width of 30 mm, seems to be wider than many other wheelsets. Despite Silca Josh saying the 105 rule was a very general rule of thumb devised along time ago, it suggests a front tire of 33.3 mm and a rear tire of 28.6 mm. Would be interested in seeing a repeated tests with: 1) a 32mm front tire, and a 28 mm rear tire; and 2) the Winspace D67s that google shows to have a front wheel width of 28 mm and a rear wheel width of 28.5 mm, which 105 rule suggests a fron tire of 26.7 mm and a rear tire of 27.1 mm; and see if the comparison test result findings still hold. Would appreciate it.
I rode 28s on a single speed for a few years and you feel EVERYTHING. Got a Domane with 32s and wow Id never go back. Rides feel so much smoother and more comfortable.
Yes, as the tire+rim is less slender the laminar flow should be impacted. Also the larger frontal area should also have an impact. The aero drag must be impacted when increasing the profile width. I understand if the high volyme tires is faster over rough surfaces, but what about smooth tarmac?
Rubber is a natural material with inherent tolerances. A tire advertised as 32 mm can measure 30 mm or vice versa. So changing a tire by such a small increment might not change anything about your bike's performance at all.
thanks for doing this! im on fairly rough pavement most of the time on 25mm tires. def going to 32s when I get back on the bike in spring. you could do a crank length comparison video but I think that's more about ergonomics and long term effects.
Can you fit 32 on your frame? People who run 25 can usually, if they're lucky, run 28. Usually you need a new bike. That may be why there are seven bikes in my apartment right now.
good question ill have to measure. hopefully. I did find someone saying they have plenty of room left over with 28s on my frame (diamondback podium Vitesse) worst case scenario I think I could run a 32 in the front and 28 in the rear.@@pierrex3226
Thanks for sharing. They really is a big difference in tire pressure. I think another good test would be to lower the pressure on the 28s and just see how the how fast and how it feels riding.
A few weeks a go i did CFD analasys on those specific wheels (roval rapide) in regards to aero drag by tire size. I tested with 26mm (stock) and 30 mm on UiT Arctic Univerity of Norway, Narvik's supercomputer. I found the wider tire to give a 1,2w saving from aero drag. With the added gain in rolling resistance it seems plausible that the increase in speed that you saw is correct. I'd like to point out however that on those wheels that a larger than normal benefit is due to the aero drag that comes from a significant improvement in C_d. My best guess would be around 20-30% of it. The front has the 35 mm wide rim that most others do not have, so do not expect an equal 2-2,6% speed increase like you did. more like 1-1.5% or worse dependent on the rim. This needs a wide rim to fully exploit the gains.
Sorry if you mentioned this somewhere else in the comments, @NorCalCycling, but what are the external and internal widths of the rims you were using? That makes a big difference, at least from what I've read on manufacturers' testing. A wider tire on a rim with a narrower internal width effects the shape of the tire and the contact patch, and the correlation between tire width and external rim width has effects on the aerodynamics.
A problem with comparing tires of different width is that normally you only have one wheelset to mount them on when you want to test back to back. Because of the aerodynamic interface with the rim, this means that both rolling resistance and aerodynamic drag will be different for each size. That's not to say that the comparison in the video is invalid, but I guess matching rim to tire would be ideal to really see if there is any significant trend!
I have seen so many videos of everyone running their own test and coming with different answers. There are too many variables, like aerodynamics, wind direction, temperature and weight. That was very hard for you to achieve those things out in the real world. But its a good start. For the most part, what I have seen from everyone running this empirical testing is that a 30 mm tire is the sweet spot.
@@jemma_19988 I was referring to road bikes on pavement. Of course track bikes on perfectly smooth wood are going to perform better with smaller tires.
Hi, do you think it may be because of aerodynamics? The Roval wheels are very wide outside, and the gap between tire and rim seemed to come down the wider the tire got. Sure "smooth is fast" but the difference could also be the aerodynamic profit too. Edit: more rubber, more grip, could aslo be down to more confidence in corners
This test is more valid for time trials than mass-start races because of the steady-state power output (in the test). The extra weight added will make a difference during a crit with hundreds of accelerations. You have to spin up all that weight every time you accelerate.
not really as it cancels out with the gained inertia, physics has proven the whole spin up thing to be a non-truth. more importantly rolling resistance is a constant loss, so uphill downhill and flats, in draft and out of it you will have significantly less RR, vs aero gains dont have much effect when going slow or in the pack. importantly RR also becomes MORE important when climbing as it is a bigger % of your resistance, the faster you go the less it becomes because air resistance is exponential, so opposite to what you said, RR should be a higher priority for climbing than TT, and the weight is no where near as important as the RR
@@jamesd5241 oh, really? Is that why F1 cars use forged magnesium wheels? The sport with nearly endless money for the best engineers in the world have somehow decided that extremely light wheels are important. Why should I ignore that?
@@RB-xv4si ha well aren't you receptive to feedback ehh! You didn't debate any of my points and used a bad reference. I love F1, they are the pinnacle of engineering, unfortunately this was a stupid reference, because i never argued that increasing weight is a benefit alone, if it was possible to lose weight without being detrimental to other factors then of course it is faster. The whole point is that it is a system pork-chop! you have to compromise, and the extra 50g of weight is meaningless when you save 8watts of rolling resistance! The F1 wheels is merely an example that they can decrease weight without affecting other factors of the system, which of course is performance enhancing. American education?
@@RB-xv4si i write again because i feel you will need it said simpler to understand, an increase in tyre weight in this instance is a compromise, but it is outweighed by the performance advantage that it gives in rolling resistance, maybe you might be able to understand thats why the tour de france was won on 28mm tires and not 23mm which would be lighter? and im sure even you can understand that in the tour de france they have a lot of micro accelerations where they have to "spin up" the wheels? Also, do you think you could get an engineering job at Red Bull F1 by telling Adrian Newey that he could make his magnesium wheels even lighter if he made that half the width?? GENIUS!
@@jamesd5241 my entire original point was that there is an entire real-world element that they didn’t consider for this test. And we won’t really know which aspect outweighs which, because it wasn’t tested. BTW, the test was comparing 28 mm tires to larger tires, not to smaller tires. So I don’t know why you brought on 23s.
Last season I went with 32c back (comfort and closing the gap between the frame for aero gains) with 28c front (aero). Been super happy with that choice
I'm an older and heavier rider (53yrs @ 215lbs) and chose to go bigger with a priority for comfort. I didn't notice any loss of speed on my usual rides (moving up from 32's) but did notice a big increase in overall comfort when sizing up. I am now riding Conti GP5000 AS TR in 35mm on my 22 Roubaix with 56psi front and 59psi rears and am very happy. The larger contact patch also feels a bit grippier as an added benefit.
I ran 32mm Conti 4 seasons on my Spec Tarmac for a few weeks, but there was only a couple of mm clearance and I noticed scratches on the frame, probably from dirt on the tires, so I switched back to 28s. To be honest I didn’t notice any difference between the 28 and 32, but I wasn’t racing and I didn’t do a scientific side-by-side. This video reminds me, I was going to eBay the 32s! 😊
SRAM uses internal rim width and the tire’s labeled width. Silca uses the width of the tire as measured. Both end up almost the same in practice, but Silca’s method is more accurate since SRAM is estimating the final tire width.
@@Adonis-qj1nq silca doesn't allow you to specify your rim's internal width which can have a significant impact on optimal pressure. All other things remaining equal, a wider rim requires less pressure. I recently went from a rim with 19.5mm internal width to a rim with 25mm internal width. The difference in required pressure is 10psi less with the same size tire.
@@chrismitsou9686 For the same tire, say a 700x28, as you increase the size of the internal rim width, the same tire will increase in its measured width. For example, my 700x28 GP5000 S TR measures 30mm on 21 internal rim width. Same exact tire moved to my 25 mm internal rim width now measures 31.5mm. It isn’t the internal rim width which impacts the pressure but the final width of the tire once it is installed onto the rim. SRAM calculator estimates final measured width of the tire/rim combo, Silca makes you measure it, which not everyone has the tools for. Put another way, say you have a 21mm internal width rim and a 700x30 tire that measures out to 31.5mm, and you have a second wheel that is 25mm internal with a 700x28 tire that also measures out to exactly the same 31.5mm, both the Silca and SRAM calculators will recommend the same pressures for both setups.
Finally! The test I've been hoping someone to do - the key for me was also using the Silca pressure calculator to fine tune the pressures. 32s for me! Kudos
Keep in mind, they have used one of the widest (or widest?) possible rim, wider then the widest tire, so going wide havent got much impact on shape and frontal area. If ur rim is smaller, these were 35mm, then u can have different experience. On the other hand, the numbers will fall in the same category anway so choose the most comfortable option.
oh wow, I'm on 32s and have moved to a hilly area with smooth roads. Was thinking I'd go to 28s when I change tyres or get deeper dish rims but I'll have to reasses.
Hi Jeff. Silca calculator is not great because it does not take into account the width of the wheel nor if it is hooked or hookless. Sram calculator is better and will give you better numbers. Anyways, I am on ENVE 3.4 ( 25mm internal and 32 external ) running 30mm GP5000 S TR and I LOVE IT. It feels fast, confy and handles super well.
Silca calculator uses the ACTUAL size of the tire, while sram is a guesswork. I have 2 gp 5k on my bike same size, same rims yet they r 2mm apart in real width, sram calculator cant handle that silca can. Different manifaturers have different real size of their tire, regardless of the numbers are the same.
@@ThomasHubik You are partial correct. SRAM takes into account the width of the wheel, labeled width of tire and use that to give you an approximate number. Also since Silca does not take Hookless into account, many times the number you get is way above the hookless max pressure! This is why you have to use SRAM if you have hookless.
@@ThomasHubik Here are the numbers I get: 25MM internal 30mm tire 32mm inflated Total bike+rider weight 180 lbs Sram: 60 psi rear and 56 front Silca: 63 rear and 62 front Wheel Manufacturer recommendation ( enve ) 58psi Sram and Enve are very close to each other’s recommendations but Silca is way higher. I know is just higher by a few PSI but on a hookless wheel a few PSI can be a big difference.
wow, amazing video. I love the look of wide tyres, specially from 35mm to 42mm. What about even going wider? Maybe there are more, but the tyres I can think of for testing with even wider tyres are the Continental Contact Urban which have a huge range of widths, from 28mm to 50mm, available. Plus they got a bit of everything: low rolling resistance, best wet grip ever and fine puncture protection. As for calculators, the Silca one is very good of course, and you also have the SRAM tyre pressure calculator, which I use 'cos it also takes into account inner rim width.
German Tour magazine made the same test but in a lab/wind tunnel, with very similar findings. However, rim widths could change that game again. Once rims are aerodynamically optimized for 34 mm, how much faster will that be? I am also surprised how narrow these Vittorias measure. Already six years ago, my 28 mm GP4000 measured 31 mm on Easton EC90 wheels. Back then, some riders caught up with me on a climb and they were absolutely convinced it is those big tires slowing me down 😂
The rim size used to make measurements changed a few years ago I think. Measurements were done on bigger rims matching current trends, so new tyres may be rated higher compared to older tyres of the same size.
Thanks for this. On an old Giant TCR disc. Fallen behind a bit. Run 25's but track pumps loses grip, have to pump them up CONSTANTLY to 97-100 psi (rear) to stop me bottoming out and to maintain them at correct pressure. Have just purchased new TCR disc frame that has far wider clearance then the old model. 32 here I come!
Hi. I have not built it up yet, likely will nearer spring. I believe 32 is max hence 32. I will likely stick with GP5000 which I think come up slightly narrower anyways so it should accommodate them fine. @@chrisc.8862
The other factor and one of the reasons Tour Pros like bigger tires, is they’re not getting “beat up”. Day to Day classic races of miles and miles, comfort also factors into daily performance.
Great video! Well I keep my 35s on for a while... on a gravel bike which I normally have 40s on. But now in winter and all the crappy roads I am on, maybe 35 is actually best but unsure
Clinchers have always been so uncomfortable it is no wonder riders in the post tub error appreciate the improved comfort of larger tires and lower pressures. Regardless, it would be nice to see some tubs in these tests, even as a benchmark, since they have 25 to 30% more hoop stress for a given diameter and pressure, and should therefore be run at even lower pressures. Also, similar to tire pressure creating the correct hoop stress for each size tire, the rim width is also a critical factor in aerodynamic drag and must be matched to the tire width. And don't forget the rotational inertia of the wheels is critical especially in a crit. Heavy wheels are a huge disadvantage in a corner...
I had a Ridley Fenix and the largest tire I could fit was a 28. I traded it for a Cube C:62 cross race gravel bike. The geometry of the bike is almost exactly the same. The Cube is a Kilo + less weight and I can now run upwards of 45c tires on 700 wheels and slightly larger on 650b wheels. The bike is much more daily useful with all the benefits of having a fast road bike. I will never go back to 25c tires
Great video. I’ve been advocating for 30’s and 32’s for a while now. Basically go as wide as your frame will allow. One thing I would love to see is a braking test or comparing cornering grip of 28 vs 32s.
On the current Vuelta I looked at the bikes and most of them use 28C tires, but for example on Lotto bikes I saw 30C. Many people don't know this, but a wider tire is much harder at the same pressure as a narrow one. If we inflate 25C at 70psi and 32C at 70psi, 32C will be faster. But if we inflate both tires to such pressures that they have identical deflection (identical comfort), then the narrow tire will be faster (weighs less - faster acceleration and lower aerodynamic resistance). I don't know how the SILCA calculator selects pressures, but maybe it doesn't take into account the fact that deflection depends on tire capacity and that's why wider tires are faster.
I tried big tyres, yes they are more confortable but they lack that snap that makes a race bike feel like a race bike. The most important thing is that I can accelerate really quickly to jump wheels and create gaps. Wider tyres are heavier and that rotational weight is slower to accelerate. The roll great when up to speed but if your on a crit with corners, slowing and speeding up, narrower tyres are better. I will always run 25's, 28's or bigger for riding around doing Z2 on crap roads.
Thanks for the video. This is very interesting. My first road bike I had 28mm tires and the handling felt a little squishy. I sent down to 25mm and it woke the handling up. I have preferred 25mm because of the handling feel rather than the comfort. How did the bigger tires affect the handling of the bike? Responsiveness and cornering primarily is what I am asking.
Since this is NorCal cycling my opinion is that 25s are better for a road like Page Mill or King’s Mountain. Cornering to me seems crisper when there are a number of switch backs or chicanes to navigate. If the road is more straight forward wider I like better for more vibration damping. I can’t believe how low pressure the Silica guidelines are. It’s very hard for me to go under 100 on 25s or 95 on 28s. Decades of habit.
Would be worth getting wider rims too to retain the benefit of aero wheels. I feel like pressure is a factor too. But 32 definitely seems like the sweet spot
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It's impressive how consistent you guys are repeating the wattage down to the watt!
Maybe they have real time monitoring and are adapting their effort...
Too bad wind wont co-operate.
@@DR_1_1 not possible to be so accurate. You would need a lab-grade test setup for that. And your position on the bike would have much more influence (on the end-time), even if you put out the same power to the watt. But this is not meant as a scientific measurement.
Unfortunately a lot of 'older' bikes don't come with the clearence to fit 30mm tyres - so going wider comes with the little pricetag of a new bike 😢😅
...which is exactly why the pros are riding wider tires, the industry wants you to think you need a new bike...
I’m limited to 25c on my updated Colnago C50. I wish I could go up to 28 but I can’t. I use 28 (which inflate to 29/30mm actually) on my other, more recent bikes
definly the worst part of old bikes. i aint sweatin' disc brakes or aero integration or electrics. i just wanna fit bigger tires as it's proven to be both faster and more comfy.
@user-if1gh4xl5h same. My poor bike sweats every time I watch one of these videos showing how going from 28-30 is a performance increase seeing as it doesn't have the clearance for 25s 😂😅. New bike coming as soon as I get the money
that's why I use an old cyclocross bike with 32c gp5000s as my road bike
Maybe do this test again using only 32c tires but different rim widths, would be interesting to see how that affects things.
YES!! I had posted saying I can fit 28s but they feel squishy on 21mm rims.
Great thought… even the same size tire on a wider rim
Your right on , I put 25c tyres on my new wheelset , Pro Lite Garda , those rims are wider than an older rim , tyres are 27 mm wide now ? Makes a huge difference on rim width ....A 32 on my new wheels would be 34 wide etc
It would be interesting to see the Strava segment "compare" view of the different runs/sizes given the varying terrain of the course. In other words, did the wider tires gain their time steadily throughout the course or were they significantly faster in certain sections and potentially slower in others, etc. Might shed some additional light on their strengths.
Yeah, we looked at that. The results seemed consistent throughout the course, with no definite places where one tire size was gaining or losing time (Similar to our cheap vs expensive tire testing video: th-cam.com/video/6x1uROsxBNk/w-d-xo.html ) Granted, GPS Data can be inconsistent which is why we were looking at lapped time comparisons.
@@williamrhardin Right on, thanks Will. Just watched the other video; the overlayed views were a nice touch.
It's amazing ! I remember a well known very experienced " Cyclo tourist "was engaged in a conversation with an equally well known "Bike Racer "in my local bike shop ! This is in the early 1980's !
The Cyclo tourist said the TDF pros should use lower gears and wider tyres !
All the racers in the shop were laughing at him !
Look at the TDF peloton today !
I have an ancient Steel Racing Bike and love my 23 tyres and my 52/42 6 speed freewheel !
There you go !
52/42, with a 6-spd corn cob 🌽 on the back! Old school, represent!! 🤘
At 1st i tried 23mm. Very rough ride.
And i switch to 28mm.
Very comfortable
As wide as your frame can take in they back.
105% external rim width rule on the front. Comfy and fast.
Been riding with 32's since 2016 love them once you are rolling around 29 30 mph the bike feels like it's floating and the tires make a humming sound, love it.
Two years ago I changed 25 for 28, because I wanted more comfort, but I was dead sure that I would loose on speed. Quite lately I learned something about pressure (never used calculators), turned out I pumped way too much..I compare myself riding 25c with 105-110psi two years ago with the present 28c and 70-75 psi and these are two different worlds in terms of comfort and stability. And now I learn that on top of that I have actually a faster bike! Amazing
The difference between the 32s and 34s is well within the margin of error. I ride 35 gravel king slicks for road riding on my gravel bike. I don’t see much of a difference between these and the 28mm Conti 5000 on my second set of wheels. Larger is less rolling resistance but if you you get too large the weight and aerodynamic penalty will set in. The question is, How large is that. For a recreational rider, I think comfort is king. At the end of the day you’ll be happier!😊
Same here but with the 38’s gk slicks. Not as comfortable as my mountain bike but relatively plush.
I’m a recreational rider. I’ve got a lovely ti road bike I managed to get 28/30s into, but I never use it, I just use my gravel bike with slick 650/47s on light 24mm ID MTB rims on the road all year. The roads are so crappy and broken especially in winter that they’re perfect, don’t puncture, and grip really well on cornering, so downhill they’re actually faster, plus in the summer I can go down any trails I like the look of while I’m out.
They aren’t aero, but neither am I!😅
In this test the 28s are too high pressure wise, the drop from the 28 to the 32 is huge compared to the 32- 34mm (31 and 33mm actual). If that is what Silca calc is stating for these lightweight riders then on that broken surface the 75/73psi is far too much and the results are not comparable. If the take 10psi out of the 28mm tyre then we'd have a proper comparison and suspect the 28mm would be same or better.
I ride Schwalbe GOne RS 35mm on my gravel bike and 28 mm Pirelli PZero on my road bike. Night and day.
Jeff I love all the race recaps and Alviso videos, but I really love seeing these science-based videos. You inspire me a lot and I’ve always been a fan since I first learned about you, keep up all the great work and thanks for the videos!
Appreciate you!!!
It's refreshing to see roadies with an open mind who can do some basic testing without letting their bias completely screw up the results. Thanks for the video.
25c feels faster yelled the old man rattling his legs off at 110psi
I think inner width and outer width of the rim will determine which tire is the fastest.
That set of roval wheels I heard test really well with wider tires.
BTW, you should also test, wider rear tires than front tires.
Peaktorque says rear tire width does not matter for areodynamics.
In addition the tire clearance of the bike also makes a huge difference. On bikes with 45mm clearance, a 40mm tire would be optimal, whereas a bike with 32mm clearance, I think a 30 or 28mm tire would be optimal.
Then there is the design of the bike. 3T, for example, has the same clearance for their Exploro Racemax model and their Exploro Ultra model. The Racemax model is optimised for smaller tires and the Ultra of course for larger tires.
Peak Torque also did a good test a while back where he discovered that running tires narrower than the rim's width (external) would not be faster.
tire/rim interface is important for aerodynamics, check out "rule of 105"
Doesn't this "rule" come into play only at relatively high yaw angles where you spend little time?
Totally agree. Enve SES has a wider inner rim, 25 mm. They say 28 mm is the fastest. I run 30mm, off the chart smooth on my North Texas county roads.
I’ve been on 32’s on my deep section Hunt’s for 2 years and absolutely love it for my daily commute. Comfy over bumps and much more forgiving 👍🏾
Commuting on a performance road bike? I love it
What do you mean communting?@@ChuckHatt
@@ChuckHattdamn right its a crit channel.
I can't get comfortable on a relaxed bike. I commute on a "high performance" bike too, just comfortable for me @@ChuckHatt
@@kasper6131commuting generally means your journey from home to work
It's cool to see the results are very similar on both tests. This is probably one of the most useful comparison videos I've seen you do, simply because most people can afford almost any tire. Awesome video!
Sweet vid. I liked how the different watts graph mirrored each other. I've been on 30mm since 2013, my butt doesn't lie!
I've been using 35s on my Orbea for over a year (with no issues & plenty of room to spare).
Luv 'em!
Back in my day, we raced on 21s. Now get off my lawn.
Back in somebody's day, they raced on 19s.
@@stefanschuchardt5734 I did once. Never again. 😆
19s only
back in my day we raced on horses!
@@stefanschuchardt5734!!!!!
NO BS, spot on, I love you guys! That's just what I want to do but without the time and resource! Plus there might be another plus for bigger tyres, there's no strong evidence, just my own feeling, that the bigger tyres feels a lot more grippier in the corner than slimmer ones. If that is true, then bigger tyres would have another plus for maybe more cornering speed, which could translates to faster descent or less race time for some guys, or a more stable "safer" downhill feeling for other less racey guys. Hope you guys could do some experiment with this. It will be interesting to see if this is really a thing.
Guessing that the aero profile of the wheel is greatly affected by the time you get to 34s. But again, in a crit race that'd probably be insignificant. Good test guys!
thanks!
It depends on the rim/tire interface. On some tire and rim combos 32s are faster than 28s (aerodynamically). On other configurations the 28s will be faster. Peak Torque did a video about this a while back. But for my riding, I prefer the cornering, braking and comfort of wider tires, sacrificing tiny bit in weight and aerodynamics.
inner rim width might help a lot with that. I have a road bike with 17mm inner width and another one with 23mm inner rim width and it's totally different how it affects the shape of the tyre
Yes, in essence PeakTorque found that the aero advantage of a deep section wheel was quickly lost once the tyre width exceeded the external width of the rims... a near flat profile being ideal. And as mentioned, a smooth transition between tyre and rim would also be very helpful, though that would normally require you to run hookless rims. I may be wrong, but I think we've got a set of Winspace Hypers on one bike (28.5mm ext) and similar Rovals... CLXII?? (30mm ext) on the other. The Winspace taper down towards the tyre a little, and are thereby *aerodynamically* optimised for a narrower tyre.... likely a 25c. I think the Rovals have a flatter profile and probably assume a 28c. BUT as this test shows, the wheel manufacturers need to be looking at optimising for 32c.... maybe even more! I also wonder if there's a substantial aero penalty from using Corsas, which have quite substantial and continuous grooves as tred. I'd bet that Contis and Goodyears would cut the air better, and maybe even grip as well given the lower pressures being run.
I seriously doubt 2mm is going to make much of a difference for anybody averaging under 40mph.
In case this helps a newer rider: I’ve only been riding for about 18 months. I switched from lower quality 25s to good 28s and the difference was clear as day.
Hi, thank you for the video.
It is an interesting comparaison.
Maybe the rim width could influence the result and the couple rim width+tire width is to taken in account to have the best and coherent aerodynamism.
Another factor could be the elevation of the ride, during a long climb with a slower speed, the weight could change the game in favor of 28mm.
But thank for this work that could help everyone to undestand the best option !
I am so happy to see racers catch up to where constructeurs were 80 years ago. :)
Seems like it has been like 3 years or so where we've jumped from calling 25mm tires wide but maybe not so fast to having to decide between various 30+ mm sizes which are both more comfy and faster. Love cycling.
P.s. this is an awesome test. Short, concise, no BS. Keep it up.
P.p.s I'll be ordering 30mm gp5000 for my sl7 to replace the 26mm turbos.
Great test guys and the results don’t surprise me all that much. I own a gravel bike with 40 mm tyres and while it is slower than my road bike with 28mm it’s not as big a difference in pure speed as you would expect and it’s so much more comfortable.
Plus one to this comment! I'm in exactly the same boat. I do the same loops in about the same times on my gravel bike on 40mm gravel slicks. But gee, it's kinder on my bones!
Sooo awesome, I want to go wider but the debate in my head is killing meee. Thank you guys for this awesome test. I’m buying 32’s thanks again. Keep it up
Hunt 48 limitless with 32mm gp5k measure to 34mm and are very close to 105 rule due to 35mm external width.
Great video. What about rim internal width, and how that affects cornering?
internal width affects the measured width of the tire. larger measured width has a bigger contact patch so better grip and confidence in corners.
@@NorCalCycling Exactly, for the nerds like me out there, for every increase of 4mm of internal rim width, it is like going up 1 tire size. A 21mm internal rim width wheel with a 30c tire will be the same as running a 25mm internal width rim on a 28c tire. Sure there will be tiny differences in contact patches and comfort due to the way the tire will stretch and shape itself on the rim, but they will measure out the same final width.
I put 32 Mondo’s on for winter riding. They measured 31 when I first put them on, but now measure 34 on my Alpinist wheel set after about 1000 miles of riding. While a smidge heavier, I don’t feel slower, and the comfort of rough desert roads is much better.
This sort of goes with what sram and zipp have stated in the past about vibration loses and that many 10s of watts can be found using wider tiers or other devices that can soak up vibration. There certainly is a trade off between aero and this but we saw many tour riders running shallower wheels with wide tiers this year. It would great to see of shallower wheels with wider tiers make an even bigger difference to what you found here.
Very helpful video. I'm trying 32s for the first time and they feel very smooth.
For the the effort here, the algo and my envy my old Trek 5200 can't see these optimal sizes. Great work guys: direct, analytical and super work. Subscribed
Would love to see this comparison up hill. Rotational weight is 3X actual at the furthest distance from the hub. With the additional mass of a larger tire+wider/deeper rim, I find them slower to accelerate and more difficult to maintain speed while climbing. 25mm handmade clinchers(Veloflex, Challenge, Vittoria, Dugast, FMB) still feel the fastest and plenty comfortable. Please include them in a climbing comparison.
Not exactly. The tires you mentioned are also very supple, which muddles the comparison.
feeling fast and actually being fast is different
Average on Tour de France is 25-26 mm.
Might have been less a decade(s) ago, although in older times like 100 years ago maybe, they had very big tyres at some point (and very bad roads!)...
For recreational road biking 28 mm feels like a good compromise to me, maybe slightly more if you are a "big guy".
@@DR_1_1tour de france average was 28-30mm and next year there will be even more people on 28-30mm
@@dirtangry No, in 2023 average was 25-26 mm.
Vandegaard won stages with 24 mm, Pogacar had 30-32 mm on several occasions, they use a lot of different gear, anyway, so it's difficult to keep track and make exact statistics.
Great video! It would also be interesting to do a test on mixed tire sizes. I saw in a bike check video that some pros had narrower tires up front, and wider in the rear. Either for better aerodynamics and comfort, or to trick their opponents.
back in the early seventies, I rode two Schwinn 10 speeds with 27"x11/4" tires. These were so comfortable.
32mm is the optimal size for my road riding , comfort from rough tarmac & gradient speed that hits the road on the sweet spot 👌
Thank you for doing this test! I’m curious to see how much of a difference a larger tire makes for me, especially as a heavier rider.
Great video, your results don't disagree with some similar tests by GCN and others. As a point of history from a now old guy racing crits/track in the 90s, Conti used to make 18mm tires with a sidewall rating of 150PSI which I ran regularly up to 170PSI on the road. I worked in a shop too and it was believed by nearly all racers that skinnier and harder tires were faster, no one was discussing hysteresis and I believed it too. But, even then we knew these skinny hard tires were not so great in the turns of a crit and my crit tire setup was to run a fat at the time front 23-25mm and a skinnier rear around 20mm, again thinking the 20mm=lower rolling resistance, both tubular. I think it's great that today's cyclists have access to so much scientific facts and data to support current trends in gear, nutrition, training, etc.. I only wish we had power meters and a strava to record back in the 90s; I raced as high as CAT 1 on the track, 3 on the road and I have no idea how fast or fit I really was.
Weird…I guess GCN gets lucky sometimes.
Remember when VREDESTEIN started to be imported to the US in the late 90s? We couldn't believe that a clincher could go up to 170psi! (Not that it was needed). 115-120 was good enough.
I still have a stash of Vredestein fortezza 23mm in the back of my closet away from sunlight...with a steel Colnago Master.
plz try 26/32, 28/32, 30/32. in motorsport, they almost always run narrower at the front and wider in the rear.
Quality content!!!! This is data even the average rider can use. Thanks a bunch. The race videos are fun but the real world testing is what brings me back again and again.
Thank you!!
@@NorCalCyclingthe tire guys need to give you a cut! We will now be buying new hoops. Strangely, I cannot find 32 mm tires anywhere…😂
There was a time when MTB tires got wider and wider (up to 3"). They have come back to 2.3" to 2.4" which appears to be the sweet spot. Likewise, widths for road tires could overshoot in the coming years (perhaps 35-38mm) and eventually come back to a more reasonable width of 28-32 mm.
It depends on the bike it depends on the terrain. If you ride glass smooth roads all the time then yes 28, 32 would be ideal. If you ride the real roads, as in Most states with crumbling infrastructure than 34, 35 even 38 may be better performing under rough conditions.
@@rider65 37mm mam w gravelu
Tour de France riders use 25-26mm on average.
Matching the profile of your rim is going to give you the fastest times unless the roads are terrible. You can see in the face-on images that the 32mm tire best matches up with the rim profile for this test which is why it was the fastest and why it was a bigger advantage for Will as aerodynamics became a bigger factor at the higher speed.
It also makes for safety. Putting a 32 mm tire on a rim designed for 23s is asking for trouble.
For crits especially. 32s and 34s have more contact patch which could increase your cornering speed or at least help the bike feel more stable when leaned way over in a corner.
GCN even put 35mm to the test downhill they were much faster
@@paxundpeace9970 ut going up...
@paxundpeace9970 i switched 23mm with 2.0" and had the same top speed during the descent. I was far more confident during cornering on the wider tyre though.
The more Comfortable you get the less stress you get. Simply means MORE POWER BABY!!!
I know this isn’t ideal for testing, but would be interesting to see this same test but on tubeless. I think you’ll see those 32’s actually measuring out at the correct size as your test confirmed 30’s is the best setup😅
A tube doesn't change the size😅
@@joneaton3366 do some experimenting on the same wheel set and you’ll be able to measure the difference when it’s only air filling up the volume of the tire vs an internal tube.
@@joneaton3366but does reduce pressure
Great give & take for the result ! instead do in wind tunnel. Now im happy with 32c and i knew it is fastest setup :)
insanity,thanks for the great video guys.I am running 28mm back(max fitting size),30mm front now.
went from 25mm to 30mm front,the ride got much smoother
Thank you for the time to do this! Wish my old Cervelo could fit something more than 25
What year is your Cervelo, ? I ride a 2013 R3 and still on 23's! After watching this video I am wondering how wide I can go, I am quite sure I can run 25, and maybe 28 in the rear, but definitely cannot run 28 in the front, Is there a noticeable difference from 23 to 25? Some of the guys I ride with, who ride newer bikes are riding on 28's, they really like them
@@philring7681 I'm on a 2011 S2. I can get a 25 Vittoria corsa on, but there's no way it could handle something bigger. I don't notice much of a difference, but I've only recently started keeping pressure of clinchers under 90. I'm sure 28+ would be noticable, but a new bike isn't in the cards for a while. Going to switch to latex this summer. Good luck
I use to be a bike mechanic. I love everything on wheels and I must say, the road cycling world may be the most stubborn, slow thinking, low evolution industry I know of.
Seems like most tech advances were made from the MTB world or other industries (cars, planes...).
I was sure that 28mm tires would be better than 25mm 15 years ago. 32mm starts to become heavy for acceleration with these 65kg riders.
The way the mentality changed when Peter Sagan started to win shows the rigidity of the mindset in road cycling.
NorCal you're awesome, love your channel and don't take it personally please.
We didn't have rims fitting 28mm without bulging, back in 2008. So that wasn't an option if you wanted to take curves at high speed.
That's true but the bulge from 25 to 28 on regular double wall rims is acceptable for casual riders who could have benefit from a much comfier, safer and faster ride for many years nonetheless.
Also lacing a road hub onto an MTB rim is no sorcery than many could have tested.@@l.d.t.6327
@@l.d.t.6327meanwhile mtb comes with 35mm internal width rims, and they’re still faster, and more comfortable. We haven’t come close to the limit on road bikes yet still
I'm glad you used the Silca calculator and actually meadured the width. My Pirelli 28 tires are nearly 30 on my Elite 50D rims. Also, you made an important point, fatter feels slower but isn't. Once these are worn out I guess I'll buy 30s.
Jeff, your video made me look into getting 32mm tires. Googling the Roval wheelset you used in the test showed a front wheel width of 35 mm and rear wheel width of 30 mm, seems to be wider than many other wheelsets. Despite Silca Josh saying the 105 rule was a very general rule of thumb devised along time ago, it suggests a front tire of 33.3 mm and a rear tire of 28.6 mm. Would be interested in seeing a repeated tests with: 1) a 32mm front tire, and a 28 mm rear tire; and 2) the Winspace D67s that google shows to have a front wheel width of 28 mm and a rear wheel width of 28.5 mm, which 105 rule suggests a fron tire of 26.7 mm and a rear tire of 27.1 mm; and see if the comparison test result findings still hold. Would appreciate it.
I rode 28s on a single speed for a few years and you feel EVERYTHING. Got a Domane with 32s and wow Id never go back. Rides feel so much smoother and more comfortable.
I got into cycling 2004. I started with 23mm tires, 53/39 crank and 11-25 cassette. I raced a circuit race on 21mm tires. Times have changed
It would be interesting seeing how the results change as speed increases and aerodynamic drag cubes up.
That Roval Rapide front wheel is 35mm wide externally. You won't see much aerodynamic penalty when tires are still narrower than the rim.
Yes, as the tire+rim is less slender the laminar flow should be impacted. Also the larger frontal area should also have an impact. The aero drag must be impacted when increasing the profile width. I understand if the high volyme tires is faster over rough surfaces, but what about smooth tarmac?
Good info. Thank you! Is there much of a difference between 30mm and 32mm? What about when you go up hill?
Rubber is a natural material with inherent tolerances. A tire advertised as 32 mm can measure 30 mm or vice versa. So changing a tire by such a small increment might not change anything about your bike's performance at all.
thanks for doing this! im on fairly rough pavement most of the time on 25mm tires. def going to 32s when I get back on the bike in spring. you could do a crank length comparison video but I think that's more about ergonomics and long term effects.
Can you fit 32 on your frame? People who run 25 can usually, if they're lucky, run 28. Usually you need a new bike. That may be why there are seven bikes in my apartment right now.
good question ill have to measure. hopefully. I did find someone saying they have plenty of room left over with 28s on my frame (diamondback podium Vitesse) worst case scenario I think I could run a 32 in the front and 28 in the rear.@@pierrex3226
I think tubeless and width also has a bearing .. but totally agree. I've been using 32s this winter and will be staying on 32s in the summertime
Thanks for sharing. They really is a big difference in tire pressure. I think another good test would be to lower the pressure on the 28s and just see how the how fast and how it feels riding.
thanks! just ordered some 32 tires. hope they fit!!
This content is gold, thank you so much for testing and finally put the slim tyre trend to the trash bin where it should belong long time ago
As a long time urban/MTB rider just now going roadie 32s are definitely my sweet spot
Backwards hat Dylan has a good take on this. Wider is definitely the future.
A few weeks a go i did CFD analasys on those specific wheels (roval rapide) in regards to aero drag by tire size. I tested with 26mm (stock) and 30 mm on UiT Arctic Univerity of Norway, Narvik's supercomputer. I found the wider tire to give a 1,2w saving from aero drag. With the added gain in rolling resistance it seems plausible that the increase in speed that you saw is correct. I'd like to point out however that on those wheels that a larger than normal benefit is due to the aero drag that comes from a significant improvement in C_d. My best guess would be around 20-30% of it. The front has the 35 mm wide rim that most others do not have, so do not expect an equal 2-2,6% speed increase like you did. more like 1-1.5% or worse dependent on the rim. This needs a wide rim to fully exploit the gains.
So why quickstep riding on 26 tyres?
Fantastic video guys - love the nuance to the test. Amazing that companies like GCN with 100x the financial backing can't do a simple test right.
Sorry if you mentioned this somewhere else in the comments, @NorCalCycling, but what are the external and internal widths of the rims you were using? That makes a big difference, at least from what I've read on manufacturers' testing. A wider tire on a rim with a narrower internal width effects the shape of the tire and the contact patch, and the correlation between tire width and external rim width has effects on the aerodynamics.
A problem with comparing tires of different width is that normally you only have one wheelset to mount them on when you want to test back to back. Because of the aerodynamic interface with the rim, this means that both rolling resistance and aerodynamic drag will be different for each size. That's not to say that the comparison in the video is invalid, but I guess matching rim to tire would be ideal to really see if there is any significant trend!
Logically the bigger tyre will be less aero in this case so the result for 32mm and 34mm is better in that case.
really liked the video guys, right to the point!!! subscribed as soon as the video started I noticed the style....
I have seen so many videos of everyone running their own test and coming with different answers. There are too many variables, like aerodynamics, wind direction, temperature and weight. That was very hard for you to achieve those things out in the real world. But its a good start. For the most part, what I have seen from everyone running this empirical testing is that a 30 mm tire is the sweet spot.
But track racers still run narrows at high pressure and they are the ones who break records
@@jemma_19988 I was referring to road bikes on pavement. Of course track bikes on perfectly smooth wood are going to perform better with smaller tires.
Hi, do you think it may be because of aerodynamics? The Roval wheels are very wide outside, and the gap between tire and rim seemed to come down the wider the tire got. Sure "smooth is fast" but the difference could also be the aerodynamic profit too.
Edit: more rubber, more grip, could aslo be down to more confidence in corners
Thanks for doing the testing for us! Very helpful!
This test is more valid for time trials than mass-start races because of the steady-state power output (in the test). The extra weight added will make a difference during a crit with hundreds of accelerations. You have to spin up all that weight every time you accelerate.
not really as it cancels out with the gained inertia, physics has proven the whole spin up thing to be a non-truth. more importantly rolling resistance is a constant loss, so uphill downhill and flats, in draft and out of it you will have significantly less RR, vs aero gains dont have much effect when going slow or in the pack.
importantly RR also becomes MORE important when climbing as it is a bigger % of your resistance, the faster you go the less it becomes because air resistance is exponential, so opposite to what you said, RR should be a higher priority for climbing than TT, and the weight is no where near as important as the RR
@@jamesd5241 oh, really? Is that why F1 cars use forged magnesium wheels? The sport with nearly endless money for the best engineers in the world have somehow decided that extremely light wheels are important. Why should I ignore that?
@@RB-xv4si ha well aren't you receptive to feedback ehh! You didn't debate any of my points and used a bad reference. I love F1, they are the pinnacle of engineering, unfortunately this was a stupid reference, because i never argued that increasing weight is a benefit alone, if it was possible to lose weight without being detrimental to other factors then of course it is faster.
The whole point is that it is a system pork-chop! you have to compromise, and the extra 50g of weight is meaningless when you save 8watts of rolling resistance!
The F1 wheels is merely an example that they can decrease weight without affecting other factors of the system, which of course is performance enhancing.
American education?
@@RB-xv4si i write again because i feel you will need it said simpler to understand,
an increase in tyre weight in this instance is a compromise, but it is outweighed by the performance advantage that it gives in rolling resistance, maybe you might be able to understand thats why the tour de france was won on 28mm tires and not 23mm which would be lighter? and im sure even you can understand that in the tour de france they have a lot of micro accelerations where they have to "spin up" the wheels?
Also, do you think you could get an engineering job at Red Bull F1 by telling Adrian Newey that he could make his magnesium wheels even lighter if he made that half the width?? GENIUS!
@@jamesd5241 my entire original point was that there is an entire real-world element that they didn’t consider for this test. And we won’t really know which aspect outweighs which, because it wasn’t tested. BTW, the test was comparing 28 mm tires to larger tires, not to smaller tires. So I don’t know why you brought on 23s.
Wow! Thanks for sharing and making this video! I will definitely go wider when I need replacement ( if my rim breaks bike can handle)
Now it would be interesting to see if the calculator is correct; test the 32’s at different pressures.
Need to test the 28mm’s at higher pressure
also with 34s
Nice analysis! Curious what the result would have been when running the 28mm at lower pressure. Thanks!!
Last season I went with 32c back (comfort and closing the gap between the frame for aero gains) with 28c front (aero). Been super happy with that choice
I'm an older and heavier rider (53yrs @ 215lbs) and chose to go bigger with a priority for comfort. I didn't notice any loss of speed on my usual rides (moving up from 32's) but did notice a big increase in overall comfort when sizing up. I am now riding Conti GP5000 AS TR in 35mm on my 22 Roubaix with 56psi front and 59psi rears and am very happy. The larger contact patch also feels a bit grippier as an added benefit.
Same here... similar age/weight and I just love the comfort of my 40mm tires (I don't race)!
The 35s fit in the non SL8 Roubaix?? Interesting, might have to try that. Whats your rim internal width?
@@j03yl33 I'm still running the original DT Swiss wheels with an internal width of 20mm. There's still plenty of clearance
I ran 32mm Conti 4 seasons on my Spec Tarmac for a few weeks, but there was only a couple of mm clearance and I noticed scratches on the frame, probably from dirt on the tires, so I switched back to 28s. To be honest I didn’t notice any difference between the 28 and 32, but I wasn’t racing and I didn’t do a scientific side-by-side. This video reminds me, I was going to eBay the 32s! 😊
Should have used the SRAM tire pressure calculator instead of silca's as it takes into consideration internal rim width for optimal tire pressure.
thanks will do for the next one!
SRAM uses internal rim width and the tire’s labeled width. Silca uses the width of the tire as measured. Both end up almost the same in practice, but Silca’s method is more accurate since SRAM is estimating the final tire width.
@@NorCalCycling No need, Silca is actually a more accurate method. See my other comment.
@@Adonis-qj1nq silca doesn't allow you to specify your rim's internal width which can have a significant impact on optimal pressure. All other things remaining equal, a wider rim requires less pressure. I recently went from a rim with 19.5mm internal width to a rim with 25mm internal width. The difference in required pressure is 10psi less with the same size tire.
@@chrismitsou9686 For the same tire, say a 700x28, as you increase the size of the internal rim width, the same tire will increase in its measured width. For example, my 700x28 GP5000 S TR measures 30mm on 21 internal rim width. Same exact tire moved to my 25 mm internal rim width now measures 31.5mm. It isn’t the internal rim width which impacts the pressure but the final width of the tire once it is installed onto the rim. SRAM calculator estimates final measured width of the tire/rim combo, Silca makes you measure it, which not everyone has the tools for.
Put another way, say you have a 21mm internal width rim and a 700x30 tire that measures out to 31.5mm, and you have a second wheel that is 25mm internal with a 700x28 tire that also measures out to exactly the same 31.5mm, both the Silca and SRAM calculators will recommend the same pressures for both setups.
Finally! The test I've been hoping someone to do - the key for me was also using the Silca pressure calculator to fine tune the pressures. 32s for me! Kudos
Keep in mind, they have used one of the widest (or widest?) possible rim, wider then the widest tire, so going wide havent got much impact on shape and frontal area. If ur rim is smaller, these were 35mm, then u can have different experience. On the other hand, the numbers will fall in the same category anway so choose the most comfortable option.
oh wow, I'm on 32s and have moved to a hilly area with smooth roads. Was thinking I'd go to 28s when I change tyres or get deeper dish rims but I'll have to reasses.
Hi Jeff. Silca calculator is not great because it does not take into account the width of the wheel nor if it is hooked or hookless. Sram calculator is better and will give you better numbers. Anyways, I am on ENVE 3.4 ( 25mm internal and 32 external ) running 30mm GP5000 S TR and I LOVE IT. It feels fast, confy and handles super well.
Silca calculator uses the ACTUAL size of the tire, while sram is a guesswork. I have 2 gp 5k on my bike same size, same rims yet they r 2mm apart in real width, sram calculator cant handle that silca can. Different manifaturers have different real size of their tire, regardless of the numbers are the same.
@@ThomasHubik You are partial correct. SRAM takes into account the width of the wheel, labeled width of tire and use that to give you an approximate number. Also since Silca does not take Hookless into account, many times the number you get is way above the hookless max pressure! This is why you have to use SRAM if you have hookless.
@@ThomasHubik Here are the numbers I get:
25MM internal
30mm tire
32mm inflated
Total bike+rider weight 180 lbs
Sram: 60 psi rear and 56 front
Silca: 63 rear and 62 front
Wheel Manufacturer recommendation ( enve ) 58psi
Sram and Enve are very close to each other’s recommendations but Silca is way higher. I know is just higher by a few PSI but on a hookless wheel a few PSI can be a big difference.
wow, amazing video. I love the look of wide tyres, specially from 35mm to 42mm. What about even going wider? Maybe there are more, but the tyres I can think of for testing with even wider tyres are the Continental Contact Urban which have a huge range of widths, from 28mm to 50mm, available. Plus they got a bit of everything: low rolling resistance, best wet grip ever and fine puncture protection.
As for calculators, the Silca one is very good of course, and you also have the SRAM tyre pressure calculator, which I use 'cos it also takes into account inner rim width.
German Tour magazine made the same test but in a lab/wind tunnel, with very similar findings. However, rim widths could change that game again. Once rims are aerodynamically optimized for 34 mm, how much faster will that be?
I am also surprised how narrow these Vittorias measure. Already six years ago, my 28 mm GP4000 measured 31 mm on Easton EC90 wheels. Back then, some riders caught up with me on a climb and they were absolutely convinced it is those big tires slowing me down 😂
The rim size used to make measurements changed a few years ago I think. Measurements were done on bigger rims matching current trends, so new tyres may be rated higher compared to older tyres of the same size.
Thanks for measuring, good call
This video proves that the best tire is the one that fits the rim the best. the 32mm fit the rim perfectly and was fastest because of that.
Thanks for this. On an old Giant TCR disc. Fallen behind a bit. Run 25's but track pumps loses grip, have to pump them up CONSTANTLY to 97-100 psi (rear) to stop me bottoming out and to maintain them at correct pressure. Have just purchased new TCR disc frame that has far wider clearance then the old model. 32 here I come!
Have you tried the 32s on the new TCR yet? is there clearance for 34 or have you reached the limt?
Hi. I have not built it up yet, likely will nearer spring. I believe 32 is max hence 32. I will likely stick with GP5000 which I think come up slightly narrower anyways so it should accommodate them fine. @@chrisc.8862
Very nice! I've been running 32s for years now.
The other factor and one of the reasons Tour Pros like bigger tires, is they’re not getting “beat up”. Day to Day classic races of miles and miles, comfort also factors into daily performance.
Great video! Well I keep my 35s on for a while... on a gravel bike which I normally have 40s on. But now in winter and all the crappy roads I am on, maybe 35 is actually best but unsure
Clinchers have always been so uncomfortable it is no wonder riders in the post tub error appreciate the improved comfort of larger tires and lower pressures. Regardless, it would be nice to see some tubs in these tests, even as a benchmark, since they have 25 to 30% more hoop stress for a given diameter and pressure, and should therefore be run at even lower pressures. Also, similar to tire pressure creating the correct hoop stress for each size tire, the rim width is also a critical factor in aerodynamic drag and must be matched to the tire width. And don't forget the rotational inertia of the wheels is critical especially in a crit. Heavy wheels are a huge disadvantage in a corner...
My stash of NOS Vredestein 23mm clinchers are laughing! They are in the back of my closet away from sunlight...
I had a Ridley Fenix and the largest tire I could fit was a 28. I traded it for a Cube C:62 cross race gravel bike. The geometry of the bike is almost exactly the same. The Cube is a Kilo + less weight and I can now run upwards of 45c tires on 700 wheels and slightly larger on 650b wheels. The bike is much more daily useful with all the benefits of having a fast road bike. I will never go back to 25c tires
I much appreciate the great content and effort
You could do a test in particular for cornering speeds. If there are gains to be had there - that is essential for crit racing...
Great video. I’ve been advocating for 30’s and 32’s for a while now. Basically go as wide as your frame will allow. One thing I would love to see is a braking test or comparing cornering grip of 28 vs 32s.
I went up from 32s to 35s and can absolutely notice the increase in cornering grip. (Conti GP5000S/TR to GP5000AS/TR)
A winspace frame with roval wheel, how the times are changing. Good video!
On the current Vuelta I looked at the bikes and most of them use 28C tires, but for example on Lotto bikes I saw 30C. Many people don't know this, but a wider tire is much harder at the same pressure as a narrow one. If we inflate 25C at 70psi and 32C at 70psi, 32C will be faster. But if we inflate both tires to such pressures that they have identical deflection (identical comfort), then the narrow tire will be faster (weighs less - faster acceleration and lower aerodynamic resistance). I don't know how the SILCA calculator selects pressures, but maybe it doesn't take into account the fact that deflection depends on tire capacity and that's why wider tires are faster.
When I travel to Japan/Asia, their roads are excellent. Everyone is on 25s. I think it's about the road quality. Go 32C for USA
I tried big tyres, yes they are more confortable but they lack that snap that makes a race bike feel like a race bike. The most important thing is that I can accelerate really quickly to jump wheels and create gaps. Wider tyres are heavier and that rotational weight is slower to accelerate. The roll great when up to speed but if your on a crit with corners, slowing and speeding up, narrower tyres are better. I will always run 25's, 28's or bigger for riding around doing Z2 on crap roads.
the weight difference between 28s and 32s is almost negligible - 30 grams. I was surprised.
Add extra sealant sloshing around for greater tyre volume. As I said, it's a 'feel' thing, actual performance results may differ.@@NorCalCycling
Thanks for the video. This is very interesting. My first road bike I had 28mm tires and the handling felt a little squishy. I sent down to 25mm and it woke the handling up. I have preferred 25mm because of the handling feel rather than the comfort. How did the bigger tires affect the handling of the bike? Responsiveness and cornering primarily is what I am asking.
Since this is NorCal cycling my opinion is that 25s are better for a road like Page Mill or King’s Mountain. Cornering to me seems crisper when there are a number of switch backs or chicanes to navigate. If the road is more straight forward wider I like better for more vibration damping.
I can’t believe how low pressure the Silica guidelines are. It’s very hard for me to go under 100 on 25s or 95 on 28s. Decades of habit.
Would be worth getting wider rims too to retain the benefit of aero wheels. I feel like pressure is a factor too. But 32 definitely seems like the sweet spot