Besides getting a ‘fast’ tyre the most important call out to me from this is to match the tyre width (or range of suitable tyre widths) to the rim. e.g. 25mm Conti 5000 have the flattest transition on my current 5yr old aero carbon wheels but I’ve got a newer, wider wheel set and 28mm Conti 5000 appear to me to give the flattest transition. And yes you can feel it on the road. So it’s clear rim width is your primary determinant of tyre with.
Drat! Going from a 76mm internal rim to 80mm internal isn't going to reduce aero drag on 27x4.5 inch studded tires. I'll just have to wait until the ice melts. Winter biking aside, these videos make me very tempted to get tires with a better compound for the spring/summer/fall.
@@seanmccuen6970 i agree, its tough to keep up with a dad on a hybrid when all you got is some expensive carbon fiber bike whose advertising is more polished then their actual product.
I don't need anything beyond 25c on my local roads and they blow out to close to 28c on my 28mm wide rims. I have a 23c that goes to 25c on the front on another bike with 28mm wide rims. I tried wider tyres but the weight and non availability in my preferred tyres . The tyres I use are Michelin power competition and tufo calibre lite 25c. The Michelin lithions also blow out generously giving around 27.6 on a 23mm internal 28mm eternal clincher rim.
Outstanding! None of the "fatter feels slow to me" slop people often spout. The final test with a moderate tyre vs a fast one was a great addition. Subbed. (FWIW I use gatorskin 25 mm so I have the worst of all worlds)
On my Polaris 69s, the 32mm GP5K isn’t much wider than the 28mm, but it is significantly taller. It’s effectively creating a deeper profile in the wheel+tire system.
The down side (potentially) and I have found this with conti tiers it can make the wheel very unstable and way more susceptible to side winds. When I had a pair of alloy hung 34s simply moving from conti to Michelin power cups transformed the stability for the better. Just my experience from a complete stranger online
These tests are great, and I sure hope you keep doing them, especially taking into account mere mortal average speeds into your testing. The cycling media and industry has somehow decided that an average speed of 40 km/h (or more) is somehow statistically significant as a reference, as if most cyclists, regardless of sex, age, fitness level or weight are fully comfortable with pushing 300W average powers on a daily basis.
@@PeakTorque my FTP is around 260-270W (used to be about 290W a couple of years ago) for 182 cm, about 87 kg and a rubbish CdA, but there's no way I'll willingly put down that much power on flats for more than a couple of minutes at a time. So far as I'm concerned, a 190-200W average power on flats already involves spending a lot of time in the upper half of my HR Z3 (over 145 BPM), which is more than plenty for my usual 4+ hour rides. It's great though to see how marginal all these aero gains are for somebody who rarely goes over 32 km/h on flats with no headwind and usually ends up with 25-26 km/h average speeds when riding solo. Again, far from what the cycling media and industry think the average road cyclist actually does.
so what? if you ride into a headwind, you go slower, if you have a tailwind, you go faster - your average speed over one year will still be whatever it is, in this case 25-26 km/h
Don't forget you can measure vibration attenuation with your other set of cheeks too! Thanks for showing that the P42 is good with 32mm tires as well - great for winter months and rougher roads.
I'm pretty sure that I'll never apply any of this to my cycling life/habits, but I sure do enjoy those videos and the amount of work that was put into them. Thank you a thousand times for that!
I've got a 28mm tyre on a narrow back rim (internal 19,6), with an ez disc cover, it does bulb - but is it as important for the back wheel as it is for the front wheel? The wheeks are giants hookless slr1 42's so tyre options are limited for an 80kg rider trying to stick under the crappy 73psi etrto limit. so its either ride cadex or suck up a 28mm bulbing gp5000 s tr
I have been quite vocal on the approximations from the previous video, you have been quite more accurate on this one. Good job on the accurate pressure adjustment between width. A table with rim and tire measured width would put things in perspective and the real point missing is a 25mm tire there.
In the 80s for time trials I used Wolber Profil 18 18mm rims with 19mm tubular tires. That was pretty common in the professional ranks. 165psi Now I use a 21 on the front and 23 in the back or a 23 in the front and 25 in the back. Also the standard setup in the 80s was Vittoria CX silk tubular in the front and a Vittoria CG cotton in the back.
Thanks for all the great videos you make. You're top 3 on YT for sure. I follow you all the time. Thanks for all you do. The best wheelsets you can ever buy are Flo, made in America. I sure would like to see you do a video comparing these to any wheels you might choose. I would say these are better than anything else you can find.
great test! I have a road bike with the "default" 28mm tyres it came with, and the inner rim is 17mm wide. Should I stay with the 28mm or go with a 32mm tyre (the max that my bike allows)?
I'm excited to see part 2 of this video on suspension losses. I've drunken the Jan Heine juice and run very wide 650B Rene Herse tires (48mm). I frequently wonder how much speed I'm losing due to aero and how much I gain from the increased suspension.
That has always been my thought. More weight rests on the rear wheel, so a bigger tire helps more there. At the same time, aero dynamics are less of an issue since there is a lot of stuff around the rear tire.
I went from Tufo S3 tubulars to 28mm GP5Ks + latex tubes on ~30x60mm aero wheels and probably saw about a 25W gain at ~30km/h. I was probably going 3-5km/h faster at the bottom of descents with no other changes. Tires, wheels and clothes are prob ground zero for low hanging fruit.... I would damn near say everything else is window dressing, especially for amateur watts. Thanks for the study
When I started using the Michelin Pro4's (well, at the time they were just Pro's) I was shocked at the substantially lower rolling resistance. When I tried the GP5K's, I didn't notice any improvement in RR, though perhaps in cornering speed, which is difficult to quantify. The Pro4's are cheaper and seem more puncture resistant. But the change from high pressure 23's to 28's made such a difference to ride comfort that I wouldn't have cared if they were slower. Since you're perhaps 15 lbs heavier than me, perhaps the wider tire is more comfortable for you. I have a recurring problem with speed being used for the quality of a ride, but then I am 78. But when I was riding 10,000 miles per year, I don't believe I was especially interested in speed on group rides unless everyone else was very fast. Then, I had a carbon fiber fork fall apart and drop me on my forehead, and my life changed completely. For two years, I was completely out of it. I was not even remembering to eat, and my previous 100kg fell to 60. I was finally taken by a cop friend to a competent neurologist who determined that I was having seizures that I couldn't remember afterward. It took about 6 months to determine the best medication and dosage, but suddenly, I became aware. I returned to riding with a vengeance on all of the latest bikes, but slowly, I became more uncomfortable with a bike made from strong fiber held together by weak resin. Finally, my cop friend who had saved my life had the entire head tube fall off of his C40, and he was lucky to only lose a finger because he was making a sharp slow uphill turn. But 5 minutes later, he would have been descending at 40 mph in heavy traffic. That was the final straw. I tried aluminum bikes and didn't care much for the noise. (The new ones like they Trek Alpha do not have that problem). Back to steel and 90s, welded frames are only marginally heavier than carbon fiber. My present Tommasini Fire that I put a steel fork on is 1/2 lb. heavier than my Trek Emonda. Somehow, I couldn't care less about the extra weight. I am shocked by the RR difference between the GP5K'S and the Vittoria Corsa.
That is a crazy and interesting experience? Which bike has the fork snap on you? And your friend's C40 must have been pretty knackered and a lot of mileage.
I stay away from full carbon bikes for that reason, and because they also cost way too much for little gain. I didn't think a carbon fork could just snap like that though. My bike frame is aluminum but of course parts like the seatpost and forks are carbon.
@@tommyfreckmann6857 That is a pretty dumb statement to make. It's definitely more fragile than aluminum for a bicycle. Once the resin starts to wear or you have a chip in the carbon, it's integrity is compromised. You can have a dent in aluminum and drop it and it'll be perfectly fine. Aluminum is 100% less fragile and more robust than carbon for a bicycle. You have to remember we are talking about something that is going to get dropped, crashed, damaged, and ridden a lot in all conditions. Carbon has a limited life span.
good suff, I am riding Zipp 303 firecrest with GP5000str. Had multiple punctures recently and was considering the Corsa NEXT as an alternative. Now will think twice...
Why do you think the p42’s had greater air resistance than the aero 35’s on 28mm tyres, shouldnt it have been the other way round? Due to the increased rim width?
Excellent channel and a great video. Do you run special tubes in your GP5000 tires? Can you confirm that the system weight for the 76psi ideal on the 28mm tires is just over 100kg? My system weight is 95kg.
Am I thn correct in understanding that the smooth transition is still the most important aspect - so right size tyre for the rim rather than wider or narrower per se?
After rewatching, the ratio between outer rim width and stated tyre width versus the aero performance makes sense: the 28mm wide Ican aero 35 wheels were faster with the 28mm tyres, and the 33.5mm wide Ascent Polaris 42 wheels were (slightly) faster with the 32mm tyres. The smaller benefit with the 42s and 32mm tyres may be because the rim is actually wider than the tyre in that case? This suggests a 1:1 ratio of rim width to stated tyre width is the best in terms of aero, what makes sense really
Top video, love the detail. Would like a pair in the tan side wall but losses on BRR puts me off big time. Don’t suppose you or anyone else has tested against black. Thanks 🙏🏻
I have light bicycle ar375 which are 25mm and bulge out to 30mm and currently run 25mm gp500Str (27mm measured), would there really be a penalty if I swapped to a 28mm F and 30mm R?
Most 23mm tyres came down in price. On 19mm wheels tyres expand to 25mm. With lowish pressure (front) they match and roll just fine. (more aero and lighter)
So the difference of (narrow rim & narrow tyr)-(wide rim & narrow tyre)=6 W (aero). What if you take into account rolling resistance and friction? High chance the gain would be bigger than those 6W
Super cool look at detailed 'stuff'. One thought - a treaded tyre like the Vittoria Corsa has virtually zero chance of achieving laminar (attached) airflow over the curve (leading edge) of the tyre. The treads act as turbulators that trip the air flow up causing it to tumble. The more prominent the tread the greater the boundary layer of turbulent air between the tyre and the smooth flowing surrounding airmass - this effectively increases the profile drag of the entire wheel. For best aero ride slicks and match the tyre width to the rim such that there is as little indentation or difference in width as possible (smooth transition). In fact tyre designers should be exploring this to make tyre/wheel combos that have zero interference to airflow - completely flush join at bead.
I think you may be getting a bit confused on this. The leading edge so-called tread on road tyres (especially the gp5000) is allegedly there on purpose as a vortex generator to energise the boundary layer and decreasing separation with the aim of lowering the total form drag. You wouldn't want laminar flow there as its not very sticky once perturbed, a turbulent boundary layer will detach later and cause a lower overall pressure drag. The same could be said for the corsa. This is why we hardly see pure slicks with no tread on the shoulders. Whether this theory works or not is another matter.
question non-topic related, what is the front light you're using? super cheeky and elegant mounting system right below the stem, I'd love to know what brand/model it is?
Vittoria Corsa cotton fanboy here. Yes, I have run older Continental GPs and Michelin Powers a few years ago, when going to Corsas I felt like I am on really fast and comfortable rail tracks. On pair prior to my last Corsa Controls I made 10Kkm rear/14Kkm front, changing them after 1st flat on the rear, while even the rear one had at least half of the profile left. And the wear is not square as on nylon tyres. From autumn I am on Controls and they have been a blast. I can even descend with them on partially snow covered roads with confidence, that's how good the grip is, no wonder that most of peloton used these in tubular version just a season or two back. I can't feel difference to standard Corsa profile in speed, while I can feel minimal penalty on flat speeds on Corsas vs older GPs, but there is no way a 19W difference in ride feel. That is more than difference if I put on alu shallow wheels vs aero carbon - which I can surely feel then. And my times on Strava are in favour of Corsa cottons, so I really must trust them more than slippery GP/Power even on climbs. And it is a much more comfortable ride even at higher pressure than on GP to match the comfort. If I was racing crits then I would think of faster tyres, but for my style of riding Corsa cotton are FTW and I am maybe even staying on Controls in summer as these are probably one of best real 4 season tyres. Saying all that I would like to try newest Michelin Power Cups, does anybody have a real world comparison between Power Cup/Corsa cotton?
I think the corsa controls are a good all round tyre but not the fastest, and the corsa speeds for me are the fastest but just don't last long enough and are pretty fragile. The last set of Powers I used cracked around the diagonal sipes on the tread. 4 tyres did this, absolutely unforgiveable!
I am 220 lbs. And am old school for sure! I still run 25mm Conti's at 120psi. Of course they will rattle the fillings out of my teeth, but absolutely zero rolling resistance, and and hard as diamonds, which means I almost never flat. I always get a kick when somebody rolls up next to me running 32's with 55 psi, riding on their rims, and expect to keep up. Then they wonder why they get their doors blown off! LOL!
Hey PT, cannot remember for the life of me your opinion about the 105% rule. 28mm wide rims usually have that larger part measuring 30 so in accordance with 105% rule with 28 tires
We need the measured width of the tires on the rims (at the PSIs you mentioned). That would be immensely helpful. I don't assume tires are their labeled width after being mounted on a rim.
Is the overall recommendation to get to as close to 1:1 measured tire width and external rim width to maximize options for rolling resistance and comfort while maintaining the aerodynamic relationship between the tire and rim?
@@PeakTorque I have a play set of Hunt 48 limitless with 32mm GP5K. WAM is 34mm+ and the external rim width is 35mm. I was pleasantly surprised how nice it rides, only the 48 Limitless wheelset weight of 1610g is a little obnoxious. I also have Polaris 69mm running 28mm GP5K and they’re great. Also own Hunt 44UD on 28mm GP5K, aaaaand since I have a serious cycling wheels addiction at the moment, I just bought my first hookless 353 NSW on 28mm GP5K S TR. Eyeing @ascentbikes P42 if they can give us 25mm hooked internal in a future version to improve 28mm tire to rim transition 😉.
There is a "105 rule" found by Hed if I remember well, that determined that the external rim width should be at least 105% of the measured tire width. Can you confirm @Peak Torque ?
Peak for the win.. Hambini's great, but forgot to mute my earphones at the start of last nights video... Had to visit A&E, as cooked my toes, when dropped sesame oil all over my left foot... My test levels went through the fucking roof though..
Very interesting data as usual. Would love to see a similar test with 25-28-30-32 mm tyres on the same rim, preferably a bit deeper (like 60 mm). Quantifying the gains and proving/debunking the 105% rule. Huge props for doing these, I've tried doing some experiments myself, had some success when gravity or RR caused most of the losses, but I also found that there simply isn't enough resolution, or the circumstances change too much to analyse aero losses/gains - without the pitot tube, of course :D
@@PeakTorque I can only imagine, that's one of the reasons I only made Excel sheets from my findings 😁 Would love to support you, just finished university, once I get a job you can count on me :D
what is going on with your seat tube? looks like there's no seatpost and only seat tube 6:40. Is your seatpost just the same colour as the frame and it's hard to see?
Great timing. I run 32mm GP5000S TR and just upgraded from 23mm external width standard rims to Roval Rapide CL II (35mm max width) aero rims. Using the "Chung method" I found a 12% lower CdA. I know a lot of that is due to eliminating the "light bulb" effect. Also, since the Rapides are optimized for 28mm I was wondering how much aero I was giving up running 32mm tires. Roval support said the differences would be quite minor and your work backs that up.
I have the same wheels as yours can i ask, does your front hub feel quite resistant? do you get many revolutions when in the fork? i understand that dt hubs need preload of the fork to allow them to work well as they feel pretty rough off the bike with out pressure. just curious how free you're front hub is.... many thanks in advance
Nice to have the data back up the intuitive result. You'd expect the wider tire to be less detrimental on a deeper wheel, to the point that a solid disc wheel would be fine with tires that would really screw up a shallow rim of the same width. Those Polaris rims are a bit of a joke in width really, you'd have to get a mountain bike tire to be in the "too wide" range 😄
Good question. I've done a bit of testing on that Cannondale Knot theory with a bulging rim lip. My tests are showing its not a good idea. I don't think the air recovers after being tripped. Don't see many other brands doing this either. With Tubular tyres, the lip is always present, which is maybe why clued up World Tour teams are not using them.
@@PeakTorque Thanks. Bottom line, the external run width matching the tire you want to ride is all important. Side note- tubulars rode so great. They may not have been aero, but they sure did feel good underneath you. 😀
Good test and video! My experience going to wider internal rims (28mm measured clincher to 30.6mm measured tubeless tire on ~55mm deep wheels) also felt like not much, if any aero penalty with tires narrower than rims. I am somewhat surprised b/c some (like Hambini) suggest that once you go to wide tires, the required chord ratio for aero benefits is well beyond 80mm deep wheels. (Which I may have misunderstood to mean that wider tires require deeper wheels to maintain same CdA). Or is the better understanding that the max width of tire/rim system is determinative, and so long as you keep the tires < rim, you can maintain CdA (or perhaps slightly improve since the overall system is deeper)?
Because he makes assumptions (doesn't test, not like this) and applies aeronautical methodologies and design principles to round spinning things with blades and axel that touch a solid surface and has a slab of meat on top. Wheels are not "fixed-point" aerofoils and don't act anything like them in many ways and need to be thought about very differently if we didn't we'd all be taking off as the first aero wheels frequently did. There is a compromise to be made between stability, comfort, hysteresis and aerodynamics he quite frequently "forgets" about 3 of them. The difference in points of a Milliermtere is not going to have any bearing on what already is a very messy airflow coming off the road you don't need a master's to know this much. A 25-30mm tier, if the rim is wide enough and has a clean edge and interface it will be "aero", it really is that simple! There will be very little difference to the point that it could be classed as margin for error, it's 5 dam millimetres. Though Roval has shown you don't necessarily need a clean interface either, look a the 26mm tier on the front of a CLX Rapide wheelset, its one of the fastest wheelsets on the planet they obviously have some very clever people working for them and throw a lot of this out the window. It's all very interesting watching these engineering principles come to light.
No it doesn’t. The sample size is way too small. It just says “that specific combo of 28 on that wheel is faster than the 28/32 on the other wheel.” There may be a combo of 32 with another wheel that’s as fast or faster…
Mmmm, yes, there might be an advantage to scaling down tire/rim profiles in order to increase aerodynamic efficiencies by way of lowering frontal and surface areas. Of course, this approach likely will come at the expense of increased CRR due to the narrower tire. It’s for sure food for thought….
Tyres with the same construction but in different widths will have lower rolling resistance with increasing width. That is at least true in any reasonable range - like 1 to 10 cm. Also you cannot get the same comfort (equals performance) on a 20 mm tyre as on a 42 mm tyre. Jan Heine did a FKT this year on 54 mm tyres. He was concerned about the width but in hindsight he doesn't think it was holding him back. So the optimal tyre width is probably larger than what you think.
Something else - bigger tire at lower pressure becomes less flat prone. Or, put another way, it takes a sharper object to puncture said tire at the lower pressure. Can only guess at what percent lower rate of flatting...... Although, folks in their black soot belching turbo-deisel 4x4 pickup trucks are still gonna' throw thumbtacks in the bike lanes 😔
Did you measure the actual width of each tyre vs the labelled width? I ask because in the last 18 months I've had 3 sets of 28mm Conti 5000's First set came stock with Canyon Endurace on the stock DT swiss rims (I believe 21mm Internal Width). In order of purchase the 28mm Conti 5000's measured (calipers) at: 30.5mm/31mm 29mm/28.3mm 27.8mm/27.3mm At my weight this results in a 14psi difference between the first and last tire.
So that means i have to choose a fast tire with the width matching the outer width of my rim. Since I got the AGX36 from nextie (40mm wide) ill chose a 40mm tire and hopefully be a little more aero?
76psi (for the 28.5mm measured width) on this test course, but that is specific to this road as i explained on the video. A rougher road will be lower, a smoother tt course would be higher.
@@PeakTorque so they basically tell you that wider tyres are better to make you buy them but in reality they are just the same size as the old ones that are apparently so much slower😂😂
@@PeakTorque I have a pair of 2020 Hypers, 19 mm inner and 26 mm outer width. On my rims, a 23 mm GP5000 is about 25 mm wide (I run it on the front wheel) and the 25 mm GP5000 is about 26 mm wide (my setup for the rear wheel so far). I also recently discovered that on my commuter bike, a 28 mm GP4000 is actually 2 mm wider than a 30 mm GP5000 ! Thats a big downsizing I guess !
@@PeakTorque Worked in the tire industry for a bit (albeit automotive). The thing I always tell other cyclists is this: You cannot outdesign a bad compound. These smaller companies can do all the tread siping and unique patterns that they want, but at the end of it, companies like Conti will have the biggest budget for compound research and there isn't much you can do about it.
Argh, I'm even more confused now. I have 19mm internal width rims (Giant SLR1) designed for 25mm tyres. I wanted to try 28mm for the comfort benefits, rolling resistance should be about the same. Hookless aside, I'm 70kilos and had no issue running 25mms for 10000km now at 80 psi. I want to go 28mm so I can drop the pressure a bit but seems like aerodynamics wise, I will be penalised ... What would you buy if you were me? :D
would've loved to have seen some winspace wheels with 25mm tyres (given they're sold as being designed to fit 25mm tyres best. my set is flush af with 25mm gp5k's). RR vs cda for 25 vs 28 would be super nice to see. my hypothesis is still that 25mm front and 28mm rear is fastest (as seen on some WT team setups), but you're the only person who could test this, lol ((btw ERTRO standard rim for measuring width is the same for 25 and 28mm tyres, 19mm inner since Jan 2020. ultra wide wheels are a meme, same as road tubeless))
I run winspace wheels with 28mm gp5000 S TR with Vittoria Inserts. 25mm isn't faster once you factor in comfort, ability to keep power down through less chatter and handling when hitting corners hard. Not to mention Tadej Pogacar is now using gp5000 TT in 28mm. Good enough for TDF winner, I'd say it's time to switch.
that transition is not at least a design issue, the eye got to like the ride as well, but on top of all that, one should remember to consider much more important issues for layman riders with the tire choice, as - grip, - durability, - how they actually drop off in corners or when braking, how they perform in their second half of their life span, - comfort/traction vs. weight/agility concerning width. Differences in the mentioned are staggering - and decisive for the pleasure and safety of the sport. I opted twice for top ranking products in a bike magazine's comparative test. Both had to get off the bike after one or two rides. They just were dangerous fun preventers and in one case have even shown very quick wear. So some self education and research pays off, as well as incrementally testing forward from a once well-proven selection.
thats why i like conti. One of the lowest Crr but durability, wet grip, and puncture resistance beats the other low Crr tyres by a mile (Corsa speed etc)
@@PeakTorque I for purpose didn't mention brands. But Conti actually IS the benchmark. Yet they (the 4000-s) drop in performance significantly when their compound isn't fresh any more. Cannot say something about the 5000-s, don't have the mileage on them (Bike since more than a year stripped for painting...). But there is one clearly superior to them: MAVIC. When fresh they are a bit less agile then Conti - but they stay as they are literally till last bit of rubber is down and you ride on the linen. And they last long. Really long. When you fit a new one of the same, other than with Conti, you don't realize that much of a sudden improvement. Further plus: Their 28mm isn't really 28, but still much more than 26. It such fits well under fenders or in older tight frames. And they look cool...
@@AGENDA_1938 Has the performance drop of Conti been documented anywhere? 1st time i hear it. I've been riding them for years and the fact that it could be the case never even occurred to me. And which Mavic tyres are you talking about?
Have you ever tested the effect of filling in the gap between sidewall and rim with a rtv silicone/caulk? I've heard rumors of pros doing it, I don't think it'd be practical for flat repair, but it would make a nearly perfect transition and I'm curious what it would save. Great video.
Would it be safe to assume that that these results would hold if the size of the lightbulb effect was constant? So if the 32mm tire and 28mm iCan rim has a 4mm lightbulb effect, would a 28mm tire and 24mm rim have the same aero losses? I assume there’s a few other things you’d have to assume as constant, but like… the same-ish aero effect?
The 28-24 would be faster than the 32-28 because it would be narrower overall. 24-24 would be much faster still So basically from fastest to slowest: 24-24 28-28 28-24 32-28
I wonder how Polaris 42 and zipp 303 firecrest compare. Only 2mm difference in depth. 303 is 2mm internally wider. Same price point too. They’re roughly the same weight too.
BTW l m shocked how low you run the tires for your weight ,you got 8kg on me , l know l d get pinch flats if l ran em that low . What kind of watts can be saved at higher pressures??
@@PeakTorque So a wider tyre on the back wheel would be an option. Here's an other testing idea: slick tyre against profiled tyre on the front (e.g. veloflex record/Michelin power against continental). Lot's of rumors, very few evidence
Although these tests with a living thing in the saddle (you) are unscientific, and uncomparable, I really like your effort and dedication. You are on the right level, but to find the right door either your tests' limitations should be better explained, or go to a more showlike approach, where everyone suspects them and the product is still entertaining.
Disagree. I have the CdA repeatability down to 0.007m^2 on some runs. I have done 200 laps on this course and everything is kept exactly the same between runs. Atmospheric conditions (if changing slightly) are dealt with by the sensor. I will leave you to work out what 0.007 CdA represents in terms of wattage repeatability. When you do enough repeats, anything is possible. My background is professional R&D engineering so I am comfortable sticking to an extremely strict protocol. I don't show even a 10th of the data that goes into this video series because; A) It is VERY time consuming. Doing the repeats, processing the raw csv files, filming, presenting the data (in a way the largest proportion of the bell curve can understand). That leaves only a finite time for video production. B) Keeping an audience is key. No one will watch or understand a 2h long presentation on CdA convergence or simultaneous equations. So I keep it as technical as possible for 15 mins approx video length. C) You can find more of part B on patreon. Cheers
Maybe I missed it, but are the tests using tubed or tubeless tires? And also, that feeling when realizing Corsa N.EXT have just been mounted to one's wheels. 😭
😂 I've had the N.EXTs on for a few thousand KMs... nothing bad to say really, but I also have some 28mm GP5000 TRS sitting in their boxes...I normally want to shoot myself in the leg rather than remount tubless tires...so I will wait...but now I REALLY want to put the GP5000s back on!
Reason why I love wiser tyres is a lot of roads where I live are absolute shit. Torn up, I encounter gravel roads when I don’t want to. So a good tyre that I can run tubeless at a low psi is good for my everyday riding.
Tire sizing is all over the place which is a bit annoying, I gotta say. I got Vittoria Corsas labelled 25c. On a rim with around 22mm internal width they measure a true 29mm. So they're just fractionally narrower than my rims at around 29.5 external. It's a fast combination. Schwalbe and Conti tires have been significantly downsized. The 25c Corsa is wider than a 28c Schwalbe One on the same rim. You really got to do your research when buying tires these days.
l run 100 psi in my 25s on 38mm deep wheel ,now with faster tires WOW difference , and 80psi on my 32s with 28mm deep rim not as fast but way more comfortable overall and less buffing from the winds, that s why its everyday bike the other for fast days in the saddle :) GRANTED two very different bikes but l know the tires sizes and psi play an important part of feel overall too when just rolling around town
So the narrower rims and tyre are faster then? I've never seen a test of a 23mm tyre on a old narrow rim vs a 28mm tyre on a wide rim - maybe it would be too embarrassing.
Narrow tyre 100% more top speed but less comfort & low grip. Just use 1:1 ratio or simply use recommended tyre size for that rim. I use my 100cc machine/motorcycle to do the test between thin & wide tyre. Obviously machine is more consistent than human. Full throttle on fat tyre, top speed at 100km/h and thin tyre at 120km/h.
I have 40mm Terra Speed gravel tyres on my gravel bike. I've ridden 32C Conti gp5000, so i'm all in favour of that for the road. But 45C road tyre makes absolutely no sense.
@@pierrex3226 not too long ago we said that about 28c tires and now they are raced at the tour; for anybody slower than world tour speeds maybe a 30c or higher could be faster assuming a good rim/tire interface; just curious really.
@@brian_simmons_ yes, but no. I'm saying that as someone who's ridden 23, 25 28 32 and 40. Road 40 is already ridiculous. Road 45 is extra ridiculous. Wider is better, up to a point.
Testing done with error-bars, love it. Liked and subscribed! I have one more question regarding aero of wider wheels, if I may. Often I read/hear that for best aero performance, the height/width ratio should be at least 3:1, e.g. if I have 30mm wide tire I would need a rim depth of 60mm, so that tire height (assuming 30mm as well)+ rim depth equals 90mm which is 3x tire width. For a 32mm tire that would require a 66mm rim depth which is quite extreme and way deeper than what you have in your test. So from your experience/knowledge, how important is that 3:1 rule actually? How big do you think the penalty would be to go to 2:1 for example? (My main events are all day solo rides with large distances, so the speed is not super high, but if an aero gains could save me 30mins of an 16h ride I'd take it. So far I am still on my standard wheels, as I am reluctant to spend tons of money for wheels that potentially are not saving me much because rim depth/ tire width are not fitting together anyway
For ultra distances you really need to be doing everything you can! Yes the speeds are lower but the cumulative time savings are huge. If its not windy, there's no downside to going deep. My advice would be go deep as you can comfortably handle, use tt clip on bars with a highish position so you're comfortable.
@@PeakTorque Thank you for your response. As I never had deep wheels before in my life, I can't judge how deep is comfortable to handle regarding crosswinds and there is so much contradicting information about it. Of course I know it also depends on the weight of the rider and I am 2,08m tall 95kg, so probably less affected. However, I also read that in ultra distance, when you tend to be super tired in the end, it get's more dangerous. Also, as the rider, espesically in my size, is of larger impact to the overall drag, it might be better to have shallower wheels, but therefore be able to keep riding in the aerobars. It makes it all super hard to judge for me, as I get alot of theoretical information but have no personal experience to gauge it. Also, I will probably buy only one set of wheels, so I can't make it wheather depend (other than typically central europe). As you are quite tall yourself and therefore closer to me than most other riders in tests I can find, what would you choose as rim depth if you had the usecase I describe? And how much time savings do you think might that provide over typical 500€ stock wheels (as in order of magnitue, are we taking 1s/1km or way more or way less). I hope it doesn't bother you that I ask so specific, but there just isn't much reliable data out there. Thank you allready for all that you provide allready :)
@@martinbrinkmoller7396 You're a tank, you can go 80mm at the back easily (some argue that a disc at the back is actually more stable because you're sitting on it), and you can absolutely handle 70mm at the front, unless you really expect nasty gushes or what not. I'm about 82kg, i've ridden 50, 60, 69mm for years. I've never ridden a disc. I wouldn't recommend 69 in the mountains to light riders. Unless there is violent sidewind (and i mean violent), handling 60mm becomes 2nd nature (once you're used to it, you just automatically correct, it's not conscious anymore), and i think anybody but feathers can handle 50mm. There's probably 5W difference between 35 and 45mm, another 5W to 60, probably a bit less than 5W to 80mm. Ball park. For the 2 wheels together @35-40kmh. The slower you go, the more it matters, because you pedal for longer. I've been riding Conti 4000/5000 + latex tubes for years. They're fast, i can attest :)
@@pierrex3226 Thank you for your answer. I have allready bought 45mm deep rims allready, so maybe not as deep as I could have gone for, but I still feel the improvement. I am riding Conti GP 5000 on them, 32mm wide, so I also got a wheelset with a 32mm external width. The combination is great
@@martinbrinkmoller7396 very good! If you climb a lot, you can't go wrong with that. If you do a lot of flat, you can save 5-10W going to 60 or 70. Now whether that's worth the money or not, that's not for me to say. Happy riding!
Well Continental claims that much of the aero efficiency of their GP5000 is due to the side thread in the tyre, so that might explain why two tyres of the same diameter perform differently, and still via an aerodynamic rather than rolling effect
Besides getting a ‘fast’ tyre the most important call out to me from this is to match the tyre width (or range of suitable tyre widths) to the rim. e.g. 25mm Conti 5000 have the flattest transition on my current 5yr old aero carbon wheels but I’ve got a newer, wider wheel set and 28mm Conti 5000 appear to me to give the flattest transition. And yes you can feel it on the road. So it’s clear rim width is your primary determinant of tyre with.
Drat! Going from a 76mm internal rim to 80mm internal isn't going to reduce aero drag on 27x4.5 inch studded tires. I'll just have to wait until the ice melts.
Winter biking aside, these videos make me very tempted to get tires with a better compound for the spring/summer/fall.
everyday we are closer to the park hybrid dad bike, they've been the answer for ages.
so 'close', yet so far away...
@@seanmccuen6970 i agree, its tough to keep up with a dad on a hybrid when all you got is some expensive carbon fiber bike whose advertising is more polished then their actual product.
I don't need anything beyond 25c on my local roads and they blow out to close to 28c on my 28mm wide rims. I have a 23c that goes to 25c on the front on another bike with 28mm wide rims. I tried wider tyres but the weight and non availability in my preferred tyres . The tyres I use are Michelin power competition and tufo calibre lite 25c. The Michelin lithions also blow out generously giving around 27.6 on a 23mm internal 28mm eternal clincher rim.
Fat road bike ftw
Outstanding! None of the "fatter feels slow to me" slop people often spout. The final test with a moderate tyre vs a fast one was a great addition. Subbed. (FWIW I use gatorskin 25 mm so I have the worst of all worlds)
"hey Margaret, that strange man is biking up and down the road again"
On my Polaris 69s, the 32mm GP5K isn’t much wider than the 28mm, but it is significantly taller. It’s effectively creating a deeper profile in the wheel+tire system.
The down side (potentially) and I have found this with conti tiers it can make the wheel very unstable and way more susceptible to side winds. When I had a pair of alloy hung 34s simply moving from conti to Michelin power cups transformed the stability for the better. Just my experience from a complete stranger online
According to measurements in the GST wind tunnel, higher tires are a disadvantage.
These tests are great, and I sure hope you keep doing them, especially taking into account mere mortal average speeds into your testing. The cycling media and industry has somehow decided that an average speed of 40 km/h (or more) is somehow statistically significant as a reference, as if most cyclists, regardless of sex, age, fitness level or weight are fully comfortable with pushing 300W average powers on a daily basis.
im about 270w to go 36kmh in an upright position where the air is thick and cold, but thats cos i have a pretty big CdA!
@@PeakTorque my FTP is around 260-270W (used to be about 290W a couple of years ago) for 182 cm, about 87 kg and a rubbish CdA, but there's no way I'll willingly put down that much power on flats for more than a couple of minutes at a time. So far as I'm concerned, a 190-200W average power on flats already involves spending a lot of time in the upper half of my HR Z3 (over 145 BPM), which is more than plenty for my usual 4+ hour rides.
It's great though to see how marginal all these aero gains are for somebody who rarely goes over 32 km/h on flats with no headwind and usually ends up with 25-26 km/h average speeds when riding solo. Again, far from what the cycling media and industry think the average road cyclist actually does.
air speed, not your speed
so what? if you ride into a headwind, you go slower, if you have a tailwind, you go faster - your average speed over one year will still be whatever it is, in this case 25-26 km/h
The people who are likely to spend that kind of money are likely to be serious competitors as well..
Don't forget you can measure vibration attenuation with your other set of cheeks too!
Thanks for showing that the P42 is good with 32mm tires as well - great for winter months and rougher roads.
I'm pretty sure that I'll never apply any of this to my cycling life/habits, but I sure do enjoy those videos and the amount of work that was put into them. Thank you a thousand times for that!
I have to say probably the same for me! But its good to know the actual data eh. Helps me sleep!
@@PeakTorque as my trainer always stated: [this; for whatever this is] won’t make you dumber.
I've got a 28mm tyre on a narrow back rim (internal 19,6), with an ez disc cover, it does bulb - but is it as important for the back wheel as it is for the front wheel? The wheeks are giants hookless slr1 42's so tyre options are limited for an 80kg rider trying to stick under the crappy 73psi etrto limit. so its either ride cadex or suck up a 28mm bulbing gp5000 s tr
Great video, of course. But is that your E46 M3 at 3:31? Gorgeous car!..
3:31 casually flexing the beamer
I thought he hurriedly pulled the shot away from it, as something embarrassing. He's in the UK, after all, not the US.
I have been quite vocal on the approximations from the previous video, you have been quite more accurate on this one.
Good job on the accurate pressure adjustment between width. A table with rim and tire measured width would put things in perspective and the real point missing is a 25mm tire there.
In the 80s for time trials I used Wolber Profil 18 18mm rims with 19mm tubular tires. That was pretty common in the professional ranks. 165psi
Now I use a 21 on the front and 23 in the back or a 23 in the front and 25 in the back.
Also the standard setup in the 80s was Vittoria CX silk tubular in the front and a Vittoria CG cotton in the back.
Probably ran on MAVIC Open 4 rims as well?
@@WowRixter probably gel330 or 280
Thanks for all the great videos you make. You're top 3 on YT for sure. I follow you all the time. Thanks for all you do. The best wheelsets you can ever buy are Flo, made in America. I sure would like to see you do a video comparing these to any wheels you might choose. I would say these are better than anything else you can find.
great test! I have a road bike with the "default" 28mm tyres it came with, and the inner rim is 17mm wide. Should I stay with the 28mm or go with a 32mm tyre (the max that my bike allows)?
I'm excited to see part 2 of this video on suspension losses. I've drunken the Jan Heine juice and run very wide 650B Rene Herse tires (48mm). I frequently wonder how much speed I'm losing due to aero and how much I gain from the increased suspension.
+1 for this
Coming soon, well, not so soon as its a shit load of testing and planning! But it will happen. Working on some accelerometer gear for the test too.
Seems that PT is deleting my link and any mention of Rene Herse’s tire test post
@@Velodictorian just ride fat bikes, the ultimate fat tire.
@@VelodictorianIs it not UA-cam’s bot deleting links?
Would like to know how just changing the rear wheel width affects the result. Guessing there’s less aero watts lost with a wider tire in the back
That has always been my thought. More weight rests on the rear wheel, so a bigger tire helps more there. At the same time, aero dynamics are less of an issue since there is a lot of stuff around the rear tire.
I went from Tufo S3 tubulars to 28mm GP5Ks + latex tubes on ~30x60mm aero wheels and probably saw about a 25W gain at ~30km/h. I was probably going 3-5km/h faster at the bottom of descents with no other changes. Tires, wheels and clothes are prob ground zero for low hanging fruit.... I would damn near say everything else is window dressing, especially for amateur watts. Thanks for the study
can you try 25mm gp5000 on the 21 internal rims? thats what im running now they measure 28mm external width
My chamois meter has long detected that the tire compound, carcass, etcetera was a bigger factor in overall wattage than rims.
Thanks for the excellent methodology and clear reporting.
Glad you enjoyed it!
When I started using the Michelin Pro4's (well, at the time they were just Pro's) I was shocked at the substantially lower rolling resistance. When I tried the GP5K's, I didn't notice any improvement in RR, though perhaps in cornering speed, which is difficult to quantify. The Pro4's are cheaper and seem more puncture resistant. But the change from high pressure 23's to 28's made such a difference to ride comfort that I wouldn't have cared if they were slower. Since you're perhaps 15 lbs heavier than me, perhaps the wider tire is more comfortable for you. I have a recurring problem with speed being used for the quality of a ride, but then I am 78. But when I was riding 10,000 miles per year, I don't believe I was especially interested in speed on group rides unless everyone else was very fast. Then, I had a carbon fiber fork fall apart and drop me on my forehead, and my life changed completely. For two years, I was completely out of it. I was not even remembering to eat, and my previous 100kg fell to 60. I was finally taken by a cop friend to a competent neurologist who determined that I was having seizures that I couldn't remember afterward. It took about 6 months to determine the best medication and dosage, but suddenly, I became aware. I returned to riding with a vengeance on all of the latest bikes, but slowly, I became more uncomfortable with a bike made from strong fiber held together by weak resin. Finally, my cop friend who had saved my life had the entire head tube fall off of his C40, and he was lucky to only lose a finger because he was making a sharp slow uphill turn. But 5 minutes later, he would have been descending at 40 mph in heavy traffic. That was the final straw. I tried aluminum bikes and didn't care much for the noise. (The new ones like they Trek Alpha do not have that problem). Back to steel and 90s, welded frames are only marginally heavier than carbon fiber. My present Tommasini Fire that I put a steel fork on is 1/2 lb. heavier than my Trek Emonda. Somehow, I couldn't care less about the extra weight. I am shocked by the RR difference between the GP5K'S and the Vittoria Corsa.
As dumb I may sound sound but even few stories of broken CF forks keep me sticking to steel. Have a great rides!
That is a crazy and interesting experience? Which bike has the fork snap on you? And your friend's C40 must have been pretty knackered and a lot of mileage.
I stay away from full carbon bikes for that reason, and because they also cost way too much for little gain. I didn't think a carbon fork could just snap like that though. My bike frame is aluminum but of course parts like the seatpost and forks are carbon.
@@username8644 aluminum is more fragile than carbon.
@@tommyfreckmann6857 That is a pretty dumb statement to make. It's definitely more fragile than aluminum for a bicycle. Once the resin starts to wear or you have a chip in the carbon, it's integrity is compromised. You can have a dent in aluminum and drop it and it'll be perfectly fine. Aluminum is 100% less fragile and more robust than carbon for a bicycle. You have to remember we are talking about something that is going to get dropped, crashed, damaged, and ridden a lot in all conditions. Carbon has a limited life span.
good suff, I am riding Zipp 303 firecrest with GP5000str. Had multiple punctures recently and was considering the Corsa NEXT as an alternative. Now will think twice...
If you aren't worried about outright speed, the tires are excellent as mile munchers. Like, truly excellent.
Why do you think the p42’s had greater air resistance than the aero 35’s on 28mm tyres, shouldnt it have been the other way round? Due to the increased rim width?
Excellent channel and a great video. Do you run special tubes in your GP5000 tires? Can you confirm that the system weight for the 76psi ideal on the 28mm tires is just over 100kg? My system weight is 95kg.
Great video. Well explained. I'm looking forward to the next video.
Am I thn correct in understanding that the smooth transition is still the most important aspect - so right size tyre for the rim rather than wider or narrower per se?
From this test, it does suggest that.
@PeakTorque what mudguard is that at 2:09? Looks super practical.
I made it, see my last video.
After rewatching, the ratio between outer rim width and stated tyre width versus the aero performance makes sense: the 28mm wide Ican aero 35 wheels were faster with the 28mm tyres, and the 33.5mm wide Ascent Polaris 42 wheels were (slightly) faster with the 32mm tyres.
The smaller benefit with the 42s and 32mm tyres may be because the rim is actually wider than the tyre in that case?
This suggests a 1:1 ratio of rim width to stated tyre width is the best in terms of aero, what makes sense really
Top video, love the detail. Would like a pair in the tan side wall but losses on BRR puts me off big time. Don’t suppose you or anyone else has tested against black.
Thanks 🙏🏻
I have light bicycle ar375 which are 25mm and bulge out to 30mm and currently run 25mm gp500Str (27mm measured), would there really be a penalty if I swapped to a 28mm F and 30mm R?
No
Always look forward to peak torque content. Thanks buddy!!!!
More to come!
Most 23mm tyres came down in price.
On 19mm wheels tyres expand to 25mm.
With lowish pressure (front) they match and roll just fine. (more aero and lighter)
So the difference of (narrow rim & narrow tyr)-(wide rim & narrow tyre)=6 W (aero). What if you take into account rolling resistance and friction? High chance the gain would be bigger than those 6W
Good to know rolling resistance is first, then matching tire size/profile to rim external width gives the best aero.
Super cool look at detailed 'stuff'. One thought - a treaded tyre like the Vittoria Corsa has virtually zero chance of achieving laminar (attached) airflow over the curve (leading edge) of the tyre. The treads act as turbulators that trip the air flow up causing it to tumble. The more prominent the tread the greater the boundary layer of turbulent air between the tyre and the smooth flowing surrounding airmass - this effectively increases the profile drag of the entire wheel. For best aero ride slicks and match the tyre width to the rim such that there is as little indentation or difference in width as possible (smooth transition). In fact tyre designers should be exploring this to make tyre/wheel combos that have zero interference to airflow - completely flush join at bead.
I think you may be getting a bit confused on this. The leading edge so-called tread on road tyres (especially the gp5000) is allegedly there on purpose as a vortex generator to energise the boundary layer and decreasing separation with the aim of lowering the total form drag. You wouldn't want laminar flow there as its not very sticky once perturbed, a turbulent boundary layer will detach later and cause a lower overall pressure drag. The same could be said for the corsa. This is why we hardly see pure slicks with no tread on the shoulders. Whether this theory works or not is another matter.
how wide was the gp5000 32mm tire on the p42, and the gp5000 28mm tire on the Ican rim?
question non-topic related, what is the front light you're using? super cheeky and elegant mounting system right below the stem, I'd love to know what brand/model it is?
Knog
Vittoria Corsa cotton fanboy here. Yes, I have run older Continental GPs and Michelin Powers a few years ago, when going to Corsas I felt like I am on really fast and comfortable rail tracks. On pair prior to my last Corsa Controls I made 10Kkm rear/14Kkm front, changing them after 1st flat on the rear, while even the rear one had at least half of the profile left. And the wear is not square as on nylon tyres. From autumn I am on Controls and they have been a blast. I can even descend with them on partially snow covered roads with confidence, that's how good the grip is, no wonder that most of peloton used these in tubular version just a season or two back. I can't feel difference to standard Corsa profile in speed, while I can feel minimal penalty on flat speeds on Corsas vs older GPs, but there is no way a 19W difference in ride feel. That is more than difference if I put on alu shallow wheels vs aero carbon - which I can surely feel then. And my times on Strava are in favour of Corsa cottons, so I really must trust them more than slippery GP/Power even on climbs. And it is a much more comfortable ride even at higher pressure than on GP to match the comfort. If I was racing crits then I would think of faster tyres, but for my style of riding Corsa cotton are FTW and I am maybe even staying on Controls in summer as these are probably one of best real 4 season tyres. Saying all that I would like to try newest Michelin Power Cups, does anybody have a real world comparison between Power Cup/Corsa cotton?
I think the corsa controls are a good all round tyre but not the fastest, and the corsa speeds for me are the fastest but just don't last long enough and are pretty fragile. The last set of Powers I used cracked around the diagonal sipes on the tread. 4 tyres did this, absolutely unforgiveable!
@@PeakTorque whoa! Then I guess the only non-cotton experiment that is out there left for me are Pirelli P Zero Race 4S.
I am 220 lbs. And am old school for sure! I still run 25mm Conti's at 120psi. Of course they will rattle the fillings out of my teeth, but absolutely zero rolling resistance, and and hard as diamonds, which means I almost never flat. I always get a kick when somebody rolls up next to me running 32's with 55 psi, riding on their rims, and expect to keep up. Then they wonder why they get their doors blown off! LOL!
Hey PT, cannot remember for the life of me your opinion about the 105% rule. 28mm wide rims usually have that larger part measuring 30 so in accordance with 105% rule with 28 tires
28 tires also expand more once you pop air in them so should be fine. As long the rim is wider than the tire. It should be ok
We need the measured width of the tires on the rims (at the PSIs you mentioned). That would be immensely helpful. I don't assume tires are their labeled width after being mounted on a rim.
Is the overall recommendation to get to as close to 1:1 measured tire width and external rim width to maximize options for rolling resistance and comfort while maintaining the aerodynamic relationship between the tire and rim?
Basically. Yes. And if using a wide tyre, make sure the rim is wide to lengthen the aerodynamic chord as much as possible.
@@PeakTorque I have a play set of Hunt 48 limitless with 32mm GP5K. WAM is 34mm+ and the external rim width is 35mm. I was pleasantly surprised how nice it rides, only the 48 Limitless wheelset weight of 1610g is a little obnoxious. I also have Polaris 69mm running 28mm GP5K and they’re great. Also own Hunt 44UD on 28mm GP5K, aaaaand since I have a serious cycling wheels addiction at the moment, I just bought my first hookless 353 NSW on 28mm GP5K S TR. Eyeing @ascentbikes P42 if they can give us 25mm hooked internal in a future version to improve 28mm tire to rim transition 😉.
There is a "105 rule" found by Hed if I remember well, that determined that the external rim width should be at least 105% of the measured tire width. Can you confirm @Peak Torque ?
Rim width should be slightly greater than tyre width for optimum aerodynamics.
@@KMS2468 105% rule was developed by Josh Poertner of Silca while he was at Zipp, developing the first 404 wheel.
Peak for the win..
Hambini's great, but forgot to mute my earphones at the start of last nights video...
Had to visit A&E, as cooked my toes, when dropped sesame oil all over my left foot...
My test levels went through the fucking roof though..
Very interesting data as usual. Would love to see a similar test with 25-28-30-32 mm tyres on the same rim, preferably a bit deeper (like 60 mm). Quantifying the gains and proving/debunking the 105% rule.
Huge props for doing these, I've tried doing some experiments myself, had some success when gravity or RR caused most of the losses, but I also found that there simply isn't enough resolution, or the circumstances change too much to analyse aero losses/gains - without the pitot tube, of course :D
Do you know how time consuming this video was to make, process and edit 😝
@@PeakTorque I can only imagine, that's one of the reasons I only made Excel sheets from my findings 😁
Would love to support you, just finished university, once I get a job you can count on me :D
what is going on with your seat tube? looks like there's no seatpost and only seat tube 6:40. Is your seatpost just the same colour as the frame and it's hard to see?
Great timing. I run 32mm GP5000S TR and just upgraded from 23mm external width standard rims to Roval Rapide CL II (35mm max width) aero rims. Using the "Chung method" I found a 12% lower CdA. I know a lot of that is due to eliminating the "light bulb" effect. Also, since the Rapides are optimized for 28mm I was wondering how much aero I was giving up running 32mm tires. Roval support said the differences would be quite minor and your work backs that up.
I have the same wheels as yours can i ask, does your front hub feel quite resistant? do you get many revolutions when in the fork? i understand that dt hubs need preload of the fork to allow them to work well as they feel pretty rough off the bike with out pressure. just curious how free you're front hub is.... many thanks in advance
I saw that E46 M3. Nice!
How about 61 mm MTB tire , any recommendations ?
Nice to have the data back up the intuitive result. You'd expect the wider tire to be less detrimental on a deeper wheel, to the point that a solid disc wheel would be fine with tires that would really screw up a shallow rim of the same width.
Those Polaris rims are a bit of a joke in width really, you'd have to get a mountain bike tire to be in the "too wide" range 😄
Howabout getting hold of a few different tyres to test if other brands can match the gp5000 tubeless
What is the result if the tire is slightly undersized, eg, a 25 tire on a rim that needs a 28 to be at 1:1?
Good question. I've done a bit of testing on that Cannondale Knot theory with a bulging rim lip. My tests are showing its not a good idea. I don't think the air recovers after being tripped. Don't see many other brands doing this either. With Tubular tyres, the lip is always present, which is maybe why clued up World Tour teams are not using them.
@@PeakTorque Thanks. Bottom line, the external run width matching the tire you want to ride is all important. Side note- tubulars rode so great. They may not have been aero, but they sure did feel good underneath you. 😀
@@rg807 Width matching is one thing, but the transition is really important too it seems.
Super video. So for those on rim brake with 17C/19C rims, does it means, that for more "aeroness" we maybe should stick on 25mm tyre?
Good test and video! My experience going to wider internal rims (28mm measured clincher to 30.6mm measured tubeless tire on ~55mm deep wheels) also felt like not much, if any aero penalty with tires narrower than rims. I am somewhat surprised b/c some (like Hambini) suggest that once you go to wide tires, the required chord ratio for aero benefits is well beyond 80mm deep wheels. (Which I may have misunderstood to mean that wider tires require deeper wheels to maintain same CdA). Or is the better understanding that the max width of tire/rim system is determinative, and so long as you keep the tires < rim, you can maintain CdA (or perhaps slightly improve since the overall system is deeper)?
Because he makes assumptions (doesn't test, not like this) and applies aeronautical methodologies and design principles to round spinning things with blades and axel that touch a solid surface and has a slab of meat on top. Wheels are not "fixed-point" aerofoils and don't act anything like them in many ways and need to be thought about very differently if we didn't we'd all be taking off as the first aero wheels frequently did. There is a compromise to be made between stability, comfort, hysteresis and aerodynamics he quite frequently "forgets" about 3 of them. The difference in points of a Milliermtere is not going to have any bearing on what already is a very messy airflow coming off the road you don't need a master's to know this much. A 25-30mm tier, if the rim is wide enough and has a clean edge and interface it will be "aero", it really is that simple! There will be very little difference to the point that it could be classed as margin for error, it's 5 dam millimetres. Though Roval has shown you don't necessarily need a clean interface either, look a the 26mm tier on the front of a CLX Rapide wheelset, its one of the fastest wheelsets on the planet they obviously have some very clever people working for them and throw a lot of this out the window. It's all very interesting watching these engineering principles come to light.
What's the make of your gilet? Been looking for a hazard (Hambini) orange one. Found it. Endura.
Does your data suggest that narrow rims, with narrower tires, require less power to maintain a specific speed?
No it doesn’t. The sample size is way too small. It just says “that specific combo of 28 on that wheel is faster than the 28/32 on the other wheel.”
There may be a combo of 32 with another wheel that’s as fast or faster…
Mmmm, yes, there might be an advantage to scaling down tire/rim profiles in order to increase aerodynamic efficiencies by way of lowering frontal and surface areas. Of course, this approach likely will come at the expense of increased CRR due to the narrower tire. It’s for sure food for thought….
Tyres with the same construction but in different widths will have lower rolling resistance with increasing width. That is at least true in any reasonable range - like 1 to 10 cm. Also you cannot get the same comfort (equals performance) on a 20 mm tyre as on a 42 mm tyre.
Jan Heine did a FKT this year on 54 mm tyres. He was concerned about the width but in hindsight he doesn't think it was holding him back. So the optimal tyre width is probably larger than what you think.
Something else - bigger tire at lower pressure becomes less flat prone.
Or, put another way, it takes a sharper object to puncture said tire at the lower pressure.
Can only guess at what percent lower rate of flatting......
Although, folks in their black soot belching turbo-deisel 4x4 pickup trucks are still gonna' throw thumbtacks in the bike lanes 😔
Did you measure the actual width of each tyre vs the labelled width? I ask because in the last 18 months I've had 3 sets of 28mm Conti 5000's First set came stock with Canyon Endurace on the stock DT swiss rims (I believe 21mm Internal Width). In order of purchase the 28mm Conti 5000's measured (calipers) at:
30.5mm/31mm
29mm/28.3mm
27.8mm/27.3mm
At my weight this results in a 14psi difference between the first and last tire.
Are you measuring all of them right after mounting, or after a first ride?
@@n0ch91c3s New, a few rides old, a few months old, and end of life. Consistent.
So that means i have to choose a fast tire with the width matching the outer width of my rim. Since I got the AGX36 from nextie (40mm wide) ill chose a 40mm tire and hopefully be a little more aero?
A 35mm tire that balloons out to 38mm on that rim is where it's at.
Can I ask what pressure you use please? I'm interested as we are same weight
76psi (for the 28.5mm measured width) on this test course, but that is specific to this road as i explained on the video. A rougher road will be lower, a smoother tt course would be higher.
would have loved to see a 25mm compared to a 28
The gp5k 28 is basically the gp4k 25mm. Same measured width. They all got downsized.
@@PeakTorque Sadly pretty much everything has been downsized today, except the prices of things.
@@PeakTorque so they basically tell you that wider tyres are better to make you buy them but in reality they are just the same size as the old ones that are apparently so much slower😂😂
@@PeakTorque I have a pair of 2020 Hypers, 19 mm inner and 26 mm outer width. On my rims, a 23 mm GP5000 is about 25 mm wide (I run it on the front wheel) and the 25 mm GP5000 is about 26 mm wide (my setup for the rear wheel so far).
I also recently discovered that on my commuter bike, a 28 mm GP4000 is actually 2 mm wider than a 30 mm GP5000 ! Thats a big downsizing I guess !
But did the diameter decrease? My frame can only take 25 tyres
In terms of rolling resistance have you looked at Veloflex vs the GP 5000? I am debating which ones to get
Not tried those for years but they were soo fragile. Conti have an unbeatable mix of speed and durability
@@PeakTorque Worked in the tire industry for a bit (albeit automotive). The thing I always tell other cyclists is this: You cannot outdesign a bad compound. These smaller companies can do all the tread siping and unique patterns that they want, but at the end of it, companies like Conti will have the biggest budget for compound research and there isn't much you can do about it.
Argh, I'm even more confused now. I have 19mm internal width rims (Giant SLR1) designed for 25mm tyres. I wanted to try 28mm for the comfort benefits, rolling resistance should be about the same. Hookless aside, I'm 70kilos and had no issue running 25mms for 10000km now at 80 psi. I want to go 28mm so I can drop the pressure a bit but seems like aerodynamics wise, I will be penalised ... What would you buy if you were me? :D
I don't see any links to videos in the description.
So what cadence is more aero?
would've loved to have seen some winspace wheels with 25mm tyres (given they're sold as being designed to fit 25mm tyres best. my set is flush af with 25mm gp5k's). RR vs cda for 25 vs 28 would be super nice to see. my hypothesis is still that 25mm front and 28mm rear is fastest (as seen on some WT team setups), but you're the only person who could test this, lol
((btw ERTRO standard rim for measuring width is the same for 25 and 28mm tyres, 19mm inner since Jan 2020. ultra wide wheels are a meme, same as road tubeless))
I run winspace wheels with 28mm gp5000 S TR with Vittoria Inserts. 25mm isn't faster once you factor in comfort, ability to keep power down through less chatter and handling when hitting corners hard.
Not to mention Tadej Pogacar is now using gp5000 TT in 28mm. Good enough for TDF winner, I'd say it's time to switch.
What’s the best tyres besides a Conti 5k? Pirellis?
that transition is not at least a design issue, the eye got to like the ride as well,
but on top of all that, one should remember to consider much more important issues for layman riders with the tire choice, as
- grip,
- durability,
- how they actually drop off in corners or when braking,
how they perform in their second half of their life span,
- comfort/traction vs. weight/agility concerning width.
Differences in the mentioned are staggering - and decisive for the pleasure and safety of the sport.
I opted twice for top ranking products in a bike magazine's comparative test.
Both had to get off the bike after one or two rides.
They just were dangerous fun preventers and in one case have even shown very quick wear.
So some self education and research pays off, as well as incrementally testing forward from a once well-proven selection.
thats why i like conti. One of the lowest Crr but durability, wet grip, and puncture resistance beats the other low Crr tyres by a mile (Corsa speed etc)
@@PeakTorque I for purpose didn't mention brands. But Conti actually IS the benchmark. Yet they (the 4000-s) drop in performance significantly when their compound isn't fresh any more. Cannot say something about the 5000-s, don't have the mileage on them (Bike since more than a year stripped for painting...).
But there is one clearly superior to them: MAVIC. When fresh they are a bit less agile then Conti - but they stay as they are literally till last bit of rubber is down and you ride on the linen. And they last long. Really long. When you fit a new one of the same, other than with Conti, you don't realize that much of a sudden improvement. Further plus: Their 28mm isn't really 28, but still much more than 26. It such fits well under fenders or in older tight frames. And they look cool...
@@AGENDA_1938 Has the performance drop of Conti been documented anywhere? 1st time i hear it. I've been riding them for years and the fact that it could be the case never even occurred to me. And which Mavic tyres are you talking about?
Have you ever tested the effect of filling in the gap between sidewall and rim with a rtv silicone/caulk? I've heard rumors of pros doing it, I don't think it'd be practical for flat repair, but it would make a nearly perfect transition and I'm curious what it would save. Great video.
I know a few guys who do it for TT but it's not UCI legal
@@PeakTorque how much can it save in aero watts? I can't see it being >10w but who knows.
@@10ktube 10 w, no way. probably a watt or two per tire at 40 kpg on average or so
Josh Porter (Silca) claims filling the gap increases rolling resistance more than it reduces aero.
I believe this was a part of the Mavic UST road system, but disappeared as a product because it was banned by UCI.
Thanks for all your hard work!
I assume this mostly pertains to the front tire?
How much of a CdA noise does Pogihair introduce?
What’s the best size tyre for 25mm internal with 40mm deep rims?
Whatever matches the outside width of the rim, when inflated.
Would it be safe to assume that that these results would hold if the size of the lightbulb effect was constant?
So if the 32mm tire and 28mm iCan rim has a 4mm lightbulb effect, would a 28mm tire and 24mm rim have the same aero losses?
I assume there’s a few other things you’d have to assume as constant, but like… the same-ish aero effect?
The 28-24 would be faster than the 32-28 because it would be narrower overall. 24-24 would be much faster still
So basically from fastest to slowest:
24-24
28-28
28-24
32-28
I wonder how Polaris 42 and zipp 303 firecrest compare. Only 2mm difference in depth. 303 is 2mm internally wider. Same price point too. They’re roughly the same weight too.
Brilliant work, thank you.
Many thanks!
Interested to see what the 42 front and 69 back wheel combination works like, Ascent are selling these as a package?
Yes we are!
BTW l m shocked how low you run the tires for your weight ,you got 8kg on me , l know l d get pinch flats if l ran em that low . What kind of watts can be saved at higher pressures??
external rim width, tire width on the rim vs external rim width matter a lot... what were those measurements?
Polaris 42 and Ican 35 on google. it's clearly spelled out on their websites.
Thank you so much for your testing efforts!! Do you think the effect comes manly from the front wheel?
Most definitely.
@@PeakTorque So a wider tyre on the back wheel would be an option.
Here's an other testing idea: slick tyre against profiled tyre on the front (e.g. veloflex record/Michelin power against continental).
Lot's of rumors, very few evidence
Is the wheel aero database already available somewhere? I’m looking at buying a new wheelset and could use some advice 😅.
It will be going up on patreon soon, I just need to finish presenting it in a more presentable way. Currently its just sheets of excel data!
Although these tests with a living thing in the saddle (you) are unscientific, and uncomparable, I really like your effort and dedication. You are on the right level, but to find the right door either your tests' limitations should be better explained, or go to a more showlike approach, where everyone suspects them and the product is still entertaining.
Disagree. I have the CdA repeatability down to 0.007m^2 on some runs. I have done 200 laps on this course and everything is kept exactly the same between runs. Atmospheric conditions (if changing slightly) are dealt with by the sensor. I will leave you to work out what 0.007 CdA represents in terms of wattage repeatability. When you do enough repeats, anything is possible. My background is professional R&D engineering so I am comfortable sticking to an extremely strict protocol. I don't show even a 10th of the data that goes into this video series because;
A) It is VERY time consuming. Doing the repeats, processing the raw csv files, filming, presenting the data (in a way the largest proportion of the bell curve can understand). That leaves only a finite time for video production.
B) Keeping an audience is key. No one will watch or understand a 2h long presentation on CdA convergence or simultaneous equations. So I keep it as technical as possible for 15 mins approx video length.
C) You can find more of part B on patreon.
Cheers
That intro is stronger than pre-mutation Covid-19 LOL
well said LOL
Fantastic data, subbing on Patreon I want to see more.
massive value! thank you!
Maybe I missed it, but are the tests using tubed or tubeless tires? And also, that feeling when realizing Corsa N.EXT have just been mounted to one's wheels. 😭
😂 I've had the N.EXTs on for a few thousand KMs... nothing bad to say really, but I also have some 28mm GP5000 TRS sitting in their boxes...I normally want to shoot myself in the leg rather than remount tubless tires...so I will wait...but now I REALLY want to put the GP5000s back on!
Reason why I love wiser tyres is a lot of roads where I live are absolute shit. Torn up, I encounter gravel roads when I don’t want to. So a good tyre that I can run tubeless at a low psi is good for my everyday riding.
Tire sizing is all over the place which is a bit annoying, I gotta say. I got Vittoria Corsas labelled 25c. On a rim with around 22mm internal width they measure a true 29mm. So they're just fractionally narrower than my rims at around 29.5 external. It's a fast combination. Schwalbe and Conti tires have been significantly downsized. The 25c Corsa is wider than a 28c Schwalbe One on the same rim. You really got to do your research when buying tires these days.
l run 100 psi in my 25s on 38mm deep wheel ,now with faster tires WOW difference , and 80psi on my 32s with 28mm deep rim not as fast but way more comfortable overall and less buffing from the winds, that s why its everyday bike the other for fast days in the saddle :) GRANTED two very different bikes but l know the tires sizes and psi play an important part of feel overall too when just rolling around town
Excellent information.
if that E46 is your car you have great car taste as well!
So the narrower rims and tyre are faster then? I've never seen a test of a 23mm tyre on a old narrow rim vs a 28mm tyre on a wide rim - maybe it would be too embarrassing.
Narrow tyre 100% more top speed but less comfort & low grip.
Just use 1:1 ratio or simply use recommended tyre size for that rim.
I use my 100cc machine/motorcycle to do the test between thin & wide tyre. Obviously machine is more consistent than human.
Full throttle on fat tyre, top speed at 100km/h and thin tyre at 120km/h.
Superb. Good work.
What’s the most aero tyre width for an e46 m3😉
255/35/19
Thank you!
I want to see a test like this with like 45c tires!
Are there any aero-ish super wide rims out there that would be optimal for a tire that wide?
Not quite that wide. The widest gravel rims are from Hunt and from 3T.
Cross country rims but they wouldn't be aero at all. I'm planning on building a set anyway. Something about 27 to 28mm internal
I have 40mm Terra Speed gravel tyres on my gravel bike. I've ridden 32C Conti gp5000, so i'm all in favour of that for the road. But 45C road tyre makes absolutely no sense.
@@pierrex3226 not too long ago we said that about 28c tires and now they are raced at the tour; for anybody slower than world tour speeds maybe a 30c or higher could be faster assuming a good rim/tire interface; just curious really.
@@brian_simmons_ yes, but no. I'm saying that as someone who's ridden 23, 25 28 32 and 40. Road 40 is already ridiculous. Road 45 is extra ridiculous. Wider is better, up to a point.
Great looking gillet what brand is it ?
Endura. I really like the warmth at the front and the zero insulation at the back.
Testing done with error-bars, love it. Liked and subscribed!
I have one more question regarding aero of wider wheels, if I may. Often I read/hear that for best aero performance, the height/width ratio should be at least 3:1, e.g. if I have 30mm wide tire I would need a rim depth of 60mm, so that tire height (assuming 30mm as well)+ rim depth equals 90mm which is 3x tire width. For a 32mm tire that would require a 66mm rim depth which is quite extreme and way deeper than what you have in your test.
So from your experience/knowledge, how important is that 3:1 rule actually? How big do you think the penalty would be to go to 2:1 for example? (My main events are all day solo rides with large distances, so the speed is not super high, but if an aero gains could save me 30mins of an 16h ride I'd take it. So far I am still on my standard wheels, as I am reluctant to spend tons of money for wheels that potentially are not saving me much because rim depth/ tire width are not fitting together anyway
For ultra distances you really need to be doing everything you can! Yes the speeds are lower but the cumulative time savings are huge. If its not windy, there's no downside to going deep. My advice would be go deep as you can comfortably handle, use tt clip on bars with a highish position so you're comfortable.
@@PeakTorque Thank you for your response. As I never had deep wheels before in my life, I can't judge how deep is comfortable to handle regarding crosswinds and there is so much contradicting information about it. Of course I know it also depends on the weight of the rider and I am 2,08m tall 95kg, so probably less affected. However, I also read that in ultra distance, when you tend to be super tired in the end, it get's more dangerous. Also, as the rider, espesically in my size, is of larger impact to the overall drag, it might be better to have shallower wheels, but therefore be able to keep riding in the aerobars.
It makes it all super hard to judge for me, as I get alot of theoretical information but have no personal experience to gauge it. Also, I will probably buy only one set of wheels, so I can't make it wheather depend (other than typically central europe). As you are quite tall yourself and therefore closer to me than most other riders in tests I can find, what would you choose as rim depth if you had the usecase I describe? And how much time savings do you think might that provide over typical 500€ stock wheels (as in order of magnitue, are we taking 1s/1km or way more or way less).
I hope it doesn't bother you that I ask so specific, but there just isn't much reliable data out there. Thank you allready for all that you provide allready :)
@@martinbrinkmoller7396 You're a tank, you can go 80mm at the back easily (some argue that a disc at the back is actually more stable because you're sitting on it), and you can absolutely handle 70mm at the front, unless you really expect nasty gushes or what not. I'm about 82kg, i've ridden 50, 60, 69mm for years. I've never ridden a disc. I wouldn't recommend 69 in the mountains to light riders. Unless there is violent sidewind (and i mean violent), handling 60mm becomes 2nd nature (once you're used to it, you just automatically correct, it's not conscious anymore), and i think anybody but feathers can handle 50mm.
There's probably 5W difference between 35 and 45mm, another 5W to 60, probably a bit less than 5W to 80mm. Ball park. For the 2 wheels together @35-40kmh. The slower you go, the more it matters, because you pedal for longer.
I've been riding Conti 4000/5000 + latex tubes for years. They're fast, i can attest :)
@@pierrex3226 Thank you for your answer. I have allready bought 45mm deep rims allready, so maybe not as deep as I could have gone for, but I still feel the improvement. I am riding Conti GP 5000 on them, 32mm wide, so I also got a wheelset with a 32mm external width. The combination is great
@@martinbrinkmoller7396 very good! If you climb a lot, you can't go wrong with that. If you do a lot of flat, you can save 5-10W going to 60 or 70. Now whether that's worth the money or not, that's not for me to say. Happy riding!
Well Continental claims that much of the aero efficiency of their GP5000 is due to the side thread in the tyre, so that might explain why two tyres of the same diameter perform differently, and still via an aerodynamic rather than rolling effect