Chinertown
Chinese Carbon Road Bikes => Road Bike Frames, Wheels & Components => Topic started by: Serge_K on April 30, 2026, 04:07:22 AM
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Hello.
https://www.bicyclerollingresistance.com/cx-gravel-reviews/continental-grand-prix-5000-s-tr-35
This came out, and confirmed the 35C is just as fast as the others. The gold standard of road cycling is not any slower in 35C, & available for purchase.
Various OEMs sell rims as wide as 36, 39, or even 41mm. (checked with Peter, Serenade / 7 tiger, Zen).
ETRTO 2024 doesn't agree with the rule of 105, i'm not sure if it's safe to just ignore that standard (assumes hooked rims, nobody seems to be making such wide rims hookless anyway).
Pogi rode that tyre on an unreleased Enve rim. He's sub 66kg. So, 66kg Roubaix vs 80+kg road, seems logical. He had 32C at the back because his frame can't clear more, i'd wager.
In summer 2023, i bought a rear wheel that's 32 wide, that was marketed as gravel only back then. I almost bought the first rims out of that mold. I didn't have the balls to order the same in front, so i went for a 28 wide rim. I regret it to this day: should have gone just as wide in front, and I "knew it", but didn't have the courage. It was pretty "out there" then. On that rear rim, the GP5000 32C measures 34.4mm. Now, pro riders often are on these very rims (32C measuring more).
This feels similar now: we know the rule of 105, and it's the best rule of thumb we have. For most people (western men c.80kg who want something that performs but also just works), i think running that 35C at the back is a no brainer. I also suspect that running the same 35C with an optimal rim is also the best choice, over a 30 or 32C: the biggest change over the years on my bikes has been comfort, and average speeds keep going up. Peace of mind while motoring through bad road patches is wonderful. Not being beaten up at the end of the ride. Not worrying (or less) about potholes, road cracks, tram tracks, gutter grills, greasy hairpins, dirty forest roads, less than ideal roads at altitude, and so on.
Currently, OEMs are selling these wide rims exclusively for gravel, to the point where some dont want to sell me a set if it's to use a 35C tyre, because of ETRTO.
Bottom line:
I think the new frame standard should become 35C (from 32C currently), assuming that means clearance for a rim that's 41mm with a 35C on it.
I'm not upgrading my daily driver for anything that can't clear that (future proofing + comfort w/o rolling resistance penalty).
Anyone to weigh in on the safety / relevance of ETRTO w, say, a 41mm external (hooked) rim w that GP5000 35C?
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So what’s the questions here ?
You want to use 35mm rubber but ETRTO is putting you off ?
I started using a 25mm (Hooked) internal rims back in 2020 when they were first available from lightbicycle. They’ve had everything on them from 28mm GP5Ks to 2.1 thunderberts.
I’m fortunate enough to have quite a few bikes and currently 10 sets of various wheels. My main take away from ETRTO is it’s massively flawed, and should be used only as a guide. Quite simply, different tyres are a tighter and looser fit on different wheels regardless of adherence to ETRTO.
I think their main objective is to keep things safe by ensuring tyre retention when the tyre is flat. However, in my experience and personal testing, it doesn’t ensure anything of the sort.
I’ve had 30mm GP5Ks on a Bontrager wheel that would always try and fall into the central channel - ETRTO compliant, but I wouldn’t ride it.
However, my current favourite is a 32mm GP5K with a tpu tube on a 32mm internal hooked and 40mm external.
Well outside of ETRTO but that tyre is absolutely not going anywhere - I’ve tested it and tried to unmount it, even when flat.
I previously use a 35mm Pro5 which was ok, but not as secure as the smaller GP5K.
My advice is, if you want to put trust in a flawed system, go with ETRTO. However, if you have the ability to test tyres for yourself - go ahead.
Disclaimer - We are all adults and can do whatever we like. Do what you feel is safe and there are probably 20+ other things more effective you can do rather than chase rule 105. ( which has kind of been debunked on newer wheels anyway )
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According to BRR these measures 34mm on 18mm IW rims, which would mean almost ~37MM on 25mm IW rims.
I think we would need U-shaped rims with wider external profile, but keeping internal 25-26mm..
So essentialy 25-26mm IW, ~37mm EW at its widest.
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If I didn't already have a pair of 32s Id be all over this for my long distance wheels. Im glad some wheel makers are finally getting with the program, but Elitewheels and a bunch of others still have 28 EW as their standard. I feel like 31-32 EW is the new minimum.
And yea I figured out a rough formula for estimating WAM from tire width and rim IW...... on the max -4 Id feel safe with (figuring 28c tires on a 24 IW rim so 31 IW for these) I wouldnt be surprised if these got to 38-39 WAM. These will really need generous frame clearances to run safely but there are def options out there. I think 32s are prob the new standard.
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Same here: for long-distance wheels I’d take a good 32c setup today, but I can see 35c becoming the obvious next step once frames catch up. The speed penalty seems much less worrying than the old road-bike mindset made it sound, while the comfort/safety margin on bad roads is real.
I’d probably shop for wide-road wheels with at least 31–32mm external now, rather than old 28mm EW “road” profiles. One AliExpress example in that direction https://it.aliexpress.com/item/1005009497190160.html (https://s.click.aliexpress.com/e/_c3uzK3S7)
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I would not buy a bike that does not fit 35c tyres if 35c is faster and more comfortable, which it seems to be.
But who decided we should stop at 35c? Did Conti and Pirelli test 40, 45 and 50 mm tyres and find 35 to be the fastest? Is there a white paper showing the data for this?
It doesn't make sense to buy a new frame until we have data that shows the actual breakpoint. At what point does a wider tyre become slower?
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I would not buy a bike that does not fit 35c tyres. If 35c is faster and more comfortable, which it seems to be.
But who decided we should stop at 35c? Did Conti and Pirelli test 40, 45 and 50 mm tyres and find 35 to be the fastest? Is there a white paper showing the data for this?
It doesn't make sense to buy a new frame until we have data that shows the actual breakpoint. At what point does a wider tyre become slower?
As will all these things, it depends.
Aero drag vs rolling resistance.
The rougher it is where you ride, the wider the tyre.
I think 35mm is just a good all rounder right now, but the wheels and frames really limit going any wider.
Yes, you can use a gravel frame for wider wheels, but that’s a different thing.
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I was a pretty early adopter of 32mm tires on the road — at least among my local groups. I went back to 28mm-30mm a couple of years ago because at my size and weight, even 32mm wasn't needed unless I was planning to hit some gravel.
Cobbles are no joke, so I would also run min 32 or 35mm tires if i was doing the Paris Roubaix sportive or smth.
However, there are plenty of trade-offs with wider tires, both in frame design and geometry, and in aero, so I am not eager to see the industry push people onto bikes that officially clear 35mm tires. Fork width is one issue. Aero-wise, superwide seems to perform best in sims, but narrow seems to do just as well IRL. With wider tires, you negate some of the effort put into the first and the second, as it's likely still optimized around the more aero 28-30mm size. So for a light bike or an endurance-type frame, I want clearance for 35mm tires, even if that means my chainstays can't be 405mm. For an aero bike, I probably still want it designed around 28-30mm tires. While people might still cram wider tires in it, I wouldn't change the design if it affects the optimization.
Rule of 105 is also irrelevant. It was coined in reference to a relatively narrow Toroidal shape and was designed to optimize tire selection for a known rim. It's not really that useful for thinking about rim selection for a tire size, nor is it really relevant for non-toroidal shapes, nor for rims that go out to 35mm at their widest point. That said, you do want a relatively smooth transition from the tire wall to the rim, or if it's designed this way, use a wider bead hook as a tripping feature. I know of very few rims that are designed this way. Oddly, there is one in the DFS catalog that is 25mm internal and 35mm external at the hooks going out to like 37 or 38mm. They even appear to have done some basic CFD. Unfortunately, it tops out at 50mm deep, but it could be an option for someone adventurous enough to go there. I didn't order these because I was worried they wouldn't clear the super-narrow 3T fork I use on my road bike.
The other problem is that tire sizing is all over the place. While 35c is clear shorthand for a 700c x 35mm tire. It doesn't quite mean the same thing as clearing a 35mm-wide tire with 6mm or 4mm on each side, which are both ISO specs, because tire manufacturers use different size references for internal width. I think, for example, Continental uses 23mm IW for 28mm and 30mm tires, but 25mm IW reference for 32mm and 35mm tires. Additionally, I think a lot of the western brand bikes that clear 34mm or 35mm tires are doing it under the ISO racing bike category for 4mm of clearance, but that really means a 30mm tire is what the bike would come with from the factory to meet regulations in a lot of countries that require 5.5 or 6mm of clearance. This is an annoying bike industry thing that probably requires a longer post to get into. I think one could also convince me that 4mm isnt really what you should be recommending for daily use, as the chance of damage is quite high.
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I have been running a 40mm ext 32mm int hooked rims with a 36mm tires (Challenge Strada Bianchi) for a couple of months now, and I love it.
Tires blow up to 40mm wide, so nice shape with respect to the rim.
I built the bike 6 years a go to be my road and gravel bike (Merlin Malt G2X in a couple of sizes smaller than my size so the stack is not too high with 2 wheelsets). The frame has 40mm tire clearance. But the times have caught up to it (as 40mm isnt really consideres gravel anymore) so now its just a roadbike with wide tires. The great part is that when I see a nice mtb/gravel trail in a forrest, I can just send it. Also, can run lower pressure.
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35mm for endurance and allroad frames yes, very confi. But nor for aero frames. Today's aero frames like Cervelo S5 and similar can run 34mm tires WAM. Y1RS does not in the rear, guess some day Y2RS will do. And on normal roads in okay condition, 30mm WAM is already quite confortable, even with stiff frames. I can't see a reason why you would need more than 32mm on an all out aero bike. In the end super wide tires for road bikes is another trend the industry wants to sell.
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35c tires are also going to function better tubeless as the typical air pressure is in a better working range for sealant than narrower tires.
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I get a lot of hate from from my road buddies because I run 25c tubeless on my road bikes. I have no problem just running them at 55-60 psi all day. They blow up close to 27-28c and I have no complaints. For my 2x road bikes I really prefer the nimble response of 25c tires. I've tried running 28c tires multiple times and I just don't like them.
On my 1x gravel bikes using a second wheelset, I'm okay running wider 30-35c slicks. For some reason I feel like 1x works better especially since I'm geared lower than 1:1 allowing me to spin at higher cadence.
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I'm also an early adopter of 32mm tires. However, as other members said, I went back to 28mm since the weight penalty was too much (100g per tire) and I'm lightweight anyway (65kg). Running Conti 28mm with TPU tubes, it hits the sweet spot for me.
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This season I've been running 32c rear and a 30c front set of GP5000 clinchers w/ TPUs. Across a variety of different wheels with internal rim widths either 23mm or 24mm. I weigh around 76kg running 58-61 PSI. So far the setup has been a great balance between race days and general endurance riding.
My latest set of XMCS wheels uses 26mm internal rim. Decided to mount in a full set of 32c front and rear GP5000 STR albeit still w/ tubes because that's all I had lying around. The tires stretch to 34.5mm-ish at the rim. 55-57 PSI.
While comfortable and super smooth, both the weight penalty and lack of road feedback is noticeable. 100% awesome for steady state efforts on not so great pavement. But anytime out of the saddle or accelerating out of a corner is when you are reminded of the larger volume. And added weight. Not mention STR tires are inherently heavier than their clincher counterparts. I think I'm gonna bit the bullet and just order a new set of 30c clinchers. They should still stretch to around 31-32mm at the rim anyway.
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I'm very much up for some fatty boom batty 35mm or bigger on my next road build.
Roads round here are like downtown Mogadishu.
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Not a huge fan of the growing width trend.
When the trend is 23->25mm, then later 28mm, I'm fine as it really smooths the ride, and even some of my older frames can support 28mm (TCR adv 2022)
But 35mm? Not only it means a new frame, which is almost ensured to have fully integrated cable routing, but much heavier tubeless tires, much slower acceleration.
My gravel/commuter bike is already running 35mm tires (close to smooth road tire, clincher, with TPU tubes), and I can definitely feel it's way less agile on climb or acceleration.
I guess I'll stick to 28mm tires for the next few years, and check if the trend is live then.
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I'm very much up for some fatty boom batty 35mm or bigger on my next road build.
Roads round here are like downtown Mogadishu.
Theres always the option of multiple wheelsets too. Im going BBW for my long distance wheelset but sticking with tried and true 28c + 60mm deep wheels for fast rides on smoother roads. In the context of selling an old build for a new build an extra wheel set isn't too bad.
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The roads I ride are usually good but I like not limiting myself on where I ride so I’m currently running 32s, and I can see myself going 35 front and rear actually. Just need to wear these current tires out.
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I’m on the fence about 35c tires. I am running 35c michelins and while they are great tires and feel way faster than the 40c kendas I took off, they do not feel as fast (nor do they objectively set faster segment times) than my 28c GP5000s. The Michis are set up tubeless and the continentals with latex tubes for minimal rolling resistance where possible.
While the shock absorption is very good with the fat tires, there are negative effects on handling with such low pressures. I’m running between 50-60 PSI with the 35s and ~75 with the 28s. They feel sluggish in turns and low speed handling is particularly negatively impacted. I also have concerns that the sacrifice they have made with thickness (the 35c GP5000s sound very thin) may make them more prone to flats compared to the other tires in the GP5k lineup.
I suspect that my happy place will be something like a 30/32c F/R combo. I am a bigger, heavier guy (195lb) so I like the shock absorption, but I don’t want to pay the price for diminishing returns.
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What brands actually offer a rim with the dimensions to run a 35c efficiently?
I've seen a few 26/35ew profiles, but that will only just fit a 32 and they only seem to come in 50 deep.
There are the gravel wheelsets who seem to settle on 30-32iw and 40-41ew - perhaps this? My Michelin Pro 5 35's run to 38-39 on a 30iw elite gravel wheelset, so that would give you more space to get the tyre/rim in line.
I feel like you need maybe a 25iw 37 ew? Really, what you want is a 32 on the front, 35 on the rear, so that would bring the 32 to about 35 and the 35 to about 38 but on the rear, ok.
They also need to be deeper - 60mm as a minimum. The wider the wheel and tyre, the deeper it needs to retain boundary attachment.
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I’m running between 50-60 PSI with the 35s and ~75 with the 28s.
Ive been similar weight as you and those pressures sound high. Though IME 5-7 PSI wont be transformative feel wise. I think tire size def helps, but the whole wheel/tire assembly (including spoke material/thickness and wheel depth) adds to the equation. I have a set of similar depth carbon spoke and steel spoke wheels on 28c GP5Ks and despite the carbon spoke wheels having more IW/lower pressures it rides way worse in the back. The wheels have different profiles as well (U vs V) so even aero is a mixed bag.
For my next build Im prob gonna get 2 wheelsets from XMCS with one being for speed/low weight and the other for comfort.
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I have XMCS 26iw 34ew for 50deep wheels for 32c GP5000S TR. They measure about 34.5mm on these rims.
I would love to have love to have rims like the new Elitewheels shown recently: 25IW 36.5EW, these would probably work fine with both 32c and 35c tires.
Would love to have like 58mm deep front wheel and 65mm deep rear wheel.
Have somebody actually tested rule of 105 in wind tunnel with wider tires? Like 30c & 32c on 25-26IW, 34EW rims... That would probably be a perfect test.
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Never forget that you can fit 35mm tires on the 2018 SWORKS VENGE… this is crazy
Ran the PRO ONE in 34c on 25mm internal rim width and it was awesome.
However clearly not as fast as 28c tires that blow up to 31-32mm anyway.
34 to 40 is absolutely great for Endurance rides, Winter rides, Recovery rides etc…
So for your N+1 bike. But for fast group rides or races I think 30-32mm is the optimal course of action. And I mean 30-32 MEASURED. For instance my 28c Michelin Power Cup balloon up to 32,5mm (+ 4,5mm!) on 26mm internal rim width with XMCS aero wheels. So you have the benefit of wide tires, but not too wide so that the 105% rule is respected with the weight saving of 28c branded tires.
240g 28c clincher tires that measure 32mm with TPU inner tubes will save you +250g over 30c tubeless
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I remember Zen having a rim with 28mm internal and 37mm external. I wonder if running a rim like that with 32mm tires would be better than 25mm internal rim with 35mm tires.
The 32mm tire should end up about 35.5mm and the rim would be 105% of it.
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I remember Zen having a rim with 28mm internal and 37mm external. I wonder if running a rim like that with 32mm tires would be better than 25mm internal rim with 35mm tires.
The 32mm tire should end up about 35.5mm and the rim would be 105% of it.
Could you link those Zen wheels (cannot find them)? They sound very nice for 35mm tires also. Closest to those I found are Nextie AGX rims (29mm int, 40mm ext). They look great, but the maximum depth is 45mm, and I'd be interested in something deeper.
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Could you link those Zen wheels (cannot find them)? They sound very nice for 35mm tires also. Closest to those I found are Nextie AGX rims (29mm int, 40mm ext). They look great, but the maximum depth is 45mm, and I'd be interested in something deeper.
I remembered wrong it was xmcs wheelset. Here's a profile pic.
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Just tried 40c Pirellis on 32 IW Tagoola XPLRs for the first time. Coming from 30F/32R Pirellis on 24IW wheels on my standard road bike. FWIW, I probably could have gone with 35s, because 40s blew up to 44 WAM. Definitely a tight fitting tire on the Tagoola wheelset.
Only one ride so far. So, I need a few weeks on them before I can give a good personal assessment.
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Yea definitely could have gone for 35.
When Zipp first launched the 32mm (or so) internal xplr rim, Goodyear made some specific (labeled size 40mm) tires for it that work well in terms of aero. When you look up the measured width of those tires on bicyclerollingresistance, they are 34mm. So they are just labeled 40 because on a 32int rim they blow up to 40.
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Tires are pretty complex engineered products. I know the ETRTO stuff isn't perfect, but let's not confidently ignore things like tread width and the tire's design and just suggest that people do things that could have serious consequences, including injury.
IMO, your best option is to follow the tire company's sizing chart. Regardless of its measured width, the number printed on the side is the ETRTO width, the one designed to be used with the compatibility chart.
For example, Continental https://www.continental-tires.com/tire-knowledge/tire-rim-combinations-etrto-standards/ When using that chart, note that the Aero 111 is narrower than the 28mm GP5000, which is roughly the same measured width as the 30mm GP5000, but if you are on a 25mm IW rim, in terms of ETRTO compatibility, the 29mm Aero 111 and the 30mm GP5000 are safe, whereas the 28mm is not. This is reflected in the tread width and the casing construction.
Pirelli and Vittoria also follow this standard for consistency. So you should consider that 35mm and 40mm road tires, unless otherwise specified, are not designed for use with rims larger than 27mm. There are tires that do vary from that, and are labeled as such on the packaging.
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I'm running 36mm tires on 32mm internal rims. At first I was apprehensive about it as well. Then after running it for a couple of months and liking it, I also saw on the Nero show's Dog or fast bike section that someone with a Canyon Aeroad was running 32mm tires on 32mm internal rims which blow up to 36mm (Nero show on March the 4th, at: 1:07:45) and racing them.
I'm sure the ETRTO have some reasons for not allowing this and thus officially one cannot recommend it. However, I am personally fine running it.
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This is reflected in the tread width and the casing construction.
Exactly this. You don't want to ride on the tires that baloon waaay too much, unless you want to ride on sidewalls... Which will be fast, but not for too long.
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I do know know how it is with the 32mm tire on 32mm into rims, but for my 36 on 32 I will never reach the side wall. Even in an extremely leaned position where my pedal already touches the ground at 45 degrees from the bottom position, we are still comfortably on the thready bit of the tire.
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Exactly this. You don't want to ride on the tires that baloon waaay too much, unless you want to ride on sidewalls... Which will be fast, but not for too long.
I dont think anyone will ever disagree w that, but it's a question of quantifying it / at which point does it matter, and also, how aggressive is the rider with cornering?
I have 32C measuring 34.4mm, there's zero issue. Also, when my rear tyre gets old, the middle of the tyre gets flat, because most of my riding is on the flat, little cornering.
Would a 35C measuring 38mm be pushing your luck? idk, but somehow i doubt it.
I do remember that bicycle rolling resistance noted that the fast Michelin road tyre in 28 i think it was, had a very narrow usable thread, with more sidewalls than competitors. So a tyre like that, you'd want to be careful with.
But i've never heard such issue w Conti GP5000.
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I'm running 36mm tires on 32mm internal rims. At first I was apprehensive about it as well. Then after running it for a couple of months and liking it, I also saw on the Nero show's Dog or fast bike section that someone with a Canyon Aeroad was running 32mm tires on 32mm internal rims which blow up to 36mm (Nero show on March the 4th, at: 1:07:45) and racing them.
I'm sure the ETRTO have some reasons for not allowing this and thus officially one cannot recommend it. However, I am personally fine running it.
At the very least, you should consider it a proper guideline for use. It's great that a bunch of influencers don't notice or care about safety either, but the consequence is shredding your sidewall (light) or dismounting your tire and crashing (severe). Why would you recommend doing something so stupid?
The risk obviously wouldn't be the same between a 36mm tire and a 32mm tire on a 32mm IW rim, but it's still well outside the tire's design unless otherwise specified. Does it really hurt to read the packaging or documentation before installing a tire? Remember that while it has its flaws, the ETRTO is an engineering standards body. Of course, people on the internet categorically know better than a group like them, right?
I dont think anyone will ever disagree w that, but it's a question of quantifying it / at which point does it matter, and also, how aggressive is the rider with cornering?
Remember that tires are not static under cornering loads, and the ground isn't always perfectly flat. Besides, sidewalls are only part of it. The other part is how the tire ends up being shaped and how that affects the different materials that are laid out in the casing. At the end of the day, it's sort of your risk until you crash someone out or damage someone else's property, but the important thing here is that this isn't just about how much the tire measures vs. marked. The size chart and the marking on the sidewall are part of the same compliance scheme, so if the ETRTO size is something, it corresponds to that size in their safety chart.
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I'm running 36mm tires on 32mm internal rims. At first I was apprehensive about it as well. Then after running it for a couple of months and liking it, I also saw on the Nero show's Dog or fast bike section that someone with a Canyon Aeroad was running 32mm tires on 32mm internal rims which blow up to 36mm (Nero show on March the 4th, at: 1:07:45) and racing them.
I'm sure the ETRTO have some reasons for not allowing this and thus officially one cannot recommend it. However, I am personally fine running it.
I think it's super dependent on use case as well. The more time you spend on the side of the tire the less room you have to deviate from ETRTO/manufacturer recs. I basically ride straight up and down like 99% of the time so I feel OK getting a little more aggressive with tire/rim combos for efficiency and comfort.
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I dont think anyone will ever disagree w that, but it's a question of quantifying it / at which point does it matter, and also, how aggressive is the rider with cornering?
I have 32C measuring 34.4mm, there's zero issue. Also, when my rear tyre gets old, the middle of the tyre gets flat, because most of my riding is on the flat, little cornering.
Would a 35C measuring 38mm be pushing your luck? idk, but somehow i doubt it.
I do remember that bicycle rolling resistance noted that the fast Michelin road tyre in 28 i think it was, had a very narrow usable thread, with more sidewalls than competitors. So a tyre like that, you'd want to be careful with.
But i've never heard such issue w Conti GP5000.
Few years ago, new Corsa Speed were introduced in size 30c and Jumbo Visma Switched onto it, around the same time they got new super wide Reserves. It was very fast, however, on that particular season, they got punctures on every race. BRR tested these tires, they figured the thread width remained the same as on 28c. Consequently, they rode on the sidewalls of already thin tire which ballooned beyond its expected width. It is very similar situation when a person is trying to fit relatively narrow tire on a very wide IW rim. So yeah, it is very likely to happen with high performance tires when one is chasing weight reduction and/or 105%.
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Good debate here and honestly when I mounted my 40c Pirelli’s to Tagoola Aero Raptors I never even thought about tire compatibility… something I would have completely looked at for my road bike.
Only a few rides in and now I am looking at how the tire is wearing when I corner. I’m not super aggressive but I have some chicanes on one of my routes that I like to test my abilities on.
Regarding the 32IW, the Tagoolas are hooked, which gives me some small modicum of confidence.
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I mean people shouldn’t be treating reference standards like this as a debate. There is a clearly wrong answer. A member of ETRTO is agreeing to design at least to spec. So if it’s not otherwise specified, a marked 40mm tire is designed for at most a 27mm IW rim. Likewise a marked 29mm tire is the smallest size generally designed for use on at most a 25mm IW rim. Assuming that a manufacturer designed the tire for a wider rim, but isn’t claiming the benefit seems unwise.
Unless you are using a tire that is claiming expanded compatibility with wider rims (e.g., the Goodyear / Zipp tires), breaking the rules means you are willingly eating into the margin of safety that is part of the design process around that tire. Obviously using a tire outside of spec only affects the risk of failure—as failure is based on probability in expected use, not a binary thing. Understanding that you are making a conscious decision to eat into the safety factor of your setup should be something at the top of your mind when you make the choice to run these ultra-wide rims for road or gravel use.
A tire hook—probably doesnt do much to lower the risk of failure caused by too small a tire since that helps more with local separation of the bead from the wheel, but IDK I am not a fan of hookless either. One thing I can’t square is the hypocrisy of claiming hookless is dangerous, but using tires outside their designed IW compatibility isn’t.
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As you understood by now, I am not as concered about it as you. But I do understand your point of view. And I like big rims and I cannot lie.
Therefore, the best solution would be (and probably will be) rims like the Duke WRX AERO 42. On the 28 internal, a 40mm (like the Michelin Pro 5) tire will probably blow up to a 43 or so, making is perfectly in line with the rim and being within ETRTO standards. Everyone happy! It will just take some time for the bike industry to adjust.
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Tried a 35mm gp5k this morning on one of Peter's 26mm wheels.
Had it on the back. Fast and comfortable, really comfortable. Currently 38mm wam.
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Kinda would like this U-shaped design, but with 26mm or max 27mm IW and then about 38mm OW at the widest part of the rim.
https://www.aliexpress.com/item/1005012068359058.html (https://www.aliexpress.com/item/1005012068359058.html)
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As usual the bike industry is overshooting. Wide tires are good (to a certain point), but of course there is no free lunch. I don't expect 35 mm tires to become common on road bikes. The sweet spot is somewhere between 28 and 32 mm, depending on riding style on road conditions.
I've recently switched from 28 to 32 mm tires on an endurance bike. The new tires run wide (WAM ~34 mm) and I definitely feel how this effects handling and acceleration. Also, while it is more comfortable, it is not like this is a groundbreaking change compared to 28 mm. And yes, I've experimented with tire pressure and made sure it's not too high.
I have also switched from 28 mm to 30 mm on a race geo bike. The difference is minimal, not really worth it.
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It's a worst-case safety net, not a performance guide. Written to prevent tire blow-off under a heavy rider on a hookless rim at max pressure with tolerance stacking. If you know your rim and your tire's actual mounted width, you can make your own call. The rule of 105 was always a heuristic, not a law.
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Tried a 35mm gp5k this morning on one of Peter's 26mm wheels.
Had it on the back. Fast and comfortable, really comfortable. Currently 38mm wam.
Cool, I added this info to the https://rubbersideup.cc/ (https://rubbersideup.cc/) database.
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thanks to my 20/20 vision, riding an enve melee that takes up to 35c tires. this will be my end game road bike.
if you guys are looking for lightweight 35c tires (not BRR tested) that weights 280g, look up IRC jetty plus 35c. They roll ridiculously well I was even dropping people right and left on viaducts and climbs.
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As you understood by now, I am not as concered about it as you. But I do understand your point of view. And I like big rims and I cannot lie.
Therefore, the best solution would be (and probably will be) rims like the Duke WRX AERO 42. On the 28 internal, a 40mm (like the Michelin Pro 5) tire will probably blow up to a 43 or so, making is perfectly in line with the rim and being within ETRTO standards. Everyone happy! It will just take some time for the bike industry to adjust.
This woud be absolutely amazing with a 38c tire like the Vittoria Corsa Pro. The WAM would be around 40mm probably, making it perfectly in line with the 105% rule ;D
make these rims in a 60mm depth and you will have a perfect setup for literally everything (except climbing lol)
In general, i would like to see more of this kind of design, with a big difference between the internal and external rim widths
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Jesse Coyle from Nero show recently tested new Tavelo bike with Pirelli 40mms and absolutely loved it
Super comfy, basically no speed loss.... hes saying this could be his only bike and hed even ditch his Incolor for it
https://youtu.be/kt0wt9LrvKg?si=7M6GgLjwWpcjXfaJ
40 is a little crazy for me and I have some smooth loops I will keep 28s for, but my next build will def focus on fitting 35s prob at 37 WAM for longer rides on crap roads.
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Jesse Coyle from Nero show recently tested new Tavelo bike with Pirelli 40mms and absolutely loved it
Super comfy, basically no speed loss.... hes saying this could be his only bike and hed even ditch his Incolor for it
https://youtu.be/kt0wt9LrvKg?si=7M6GgLjwWpcjXfaJ
40 is a little crazy for me and I have some smooth loops I will keep 28s for, but my next build will def focus on fitting 35s prob at 37 WAM for longer rides on crap roads.
To be honest I was a bit surprised by his numbers. We should keep in mind that he did not really do any real scientific testing, he was comparing speeds recorded across many months, with different frames, different weather, different clothes, etc. (basically everything was different lol). Anyway really interesting.
To me the most important take is that on tarmac, gravel bikes are just better than road bikes for 99% of people, and that endrance bikes are basically pointless. Many of us have been saying this for a while and it's nice to see other influential people realizing it as well. Even the bit about the geometry was spot on, I really think that the geometry of modern "race" gravel bikes is just the best geometry for road bikes. (btw I also think that the geometry of modern grave bikes is bad for what they are supposed to do, but I guess this is a topic for another thread ;) )
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The Nero show tests were done on a pan flat crit circuit, no significant hills. If you were riding with a lot of climbing, I expect the weight of a 40mm tyre would be very noticeable.
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Nero show was good, and echoed my current thoughts.
Still loving the 35 gp5k's - 38wam. If they come out with 40's I'll give them a go.
I don't do alpine ascents, but they are generally giving me the same or faster average on my rides, and using a gravel frame instead of previous road bike.
And it's very very comfortable!
(https://weightweenies.starbike.com/forum/download/file.php?id=131054&t=1)
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To be honest I was a bit surprised by his numbers. We should keep in mind that he did not really do any real scientific testing, he was comparing speeds recorded across many months, with different frames, different weather, different clothes, etc. (basically everything was different lol). Anyway really interesting.
To me the most important take is that on tarmac, gravel bikes are just better than road bikes for 99% of people, and that endrance bikes are basically pointless. Many of us have been saying this for a while and it's nice to see other influential people realizing it as well. Even the bit about the geometry was spot on, I really think that the geometry of modern "race" gravel bikes is just the best geometry for road bikes. (btw I also think that the geometry of modern grave bikes is bad for what they are supposed to do, but I guess this is a topic for another thread ;) )
Gravel bikes just dont have the geometry I want. I like TT-ish geometry (steeper STAs, racy trail and more reach). Gravel bikes are starting to get more racy with geometry but road bikes like the LTK-266-D SL and Voice Velo Echo are much closer to ticking all my boxes. For folks who can handle + enjoy more aggressive geometry gravel won't do. We need race bikes w/big tire clearance and built in compliance.
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Gravel bikes just dont have the geometry I want. I like TT-ish geometry (steeper STAs, racy trail and more reach). Gravel bikes are starting to get more racy with geometry but road bikes like the LTK-266-D SL and Voice Velo Echo are much closer to ticking all my boxes. For folks who can handle + enjoy more aggressive geometry gravel won't do. We need race bikes w/big tire clearance and built in compliance.
Bottom bracket drop 94
Stack 575
Reach 440
Seat angle 76
Head angle 72
Wheelbase 1050
Fork trail 45
Chainstays 425
Granted, chainstays are a bit long and maybe head angle not steep enough but it's nearly there :-)
(https://weightweenies.starbike.com/forum/download/file.php?id=130801&t=1)
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The Nero show tests were done on a pan flat crit circuit, no significant hills. If you were riding with a lot of climbing, I expect the weight of a 40mm tyre would be very noticeable.
I love wider tires they're more comfortable and provides way more confidence cornering agressively. They usually feel slower but from my experience this mostly an imporession, the difference in speed is often negligable as long as you pick the correct tire pressure and you pick good tires. As an example, I recently switched my road wheelset (Continental GP5000 S TR 32mm) with my gravel wheelset (Schwalbe G-one RS pro 50mm) on my bike, while they felt way more sluggish when I'm looking at my time on section of flat smooth roads the difference is marginal. My gravel wheelset is slightly deeper 60mm vs 50mm so that might play a role, and the aerodynamic gains of the deeper wheelset might compensate for the slight rolling resistance penalty.
I don't think weight makes such a difference either. Between the 28mm and 40mm version of the Pirellu tire there is only 130g of differece, so with two tires it's around 260g, so around half a 500ml water bottle. You're own weight probably varies more than that during a long ride.
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Bottom bracket drop 94
Stack 575
Reach 440
Seat angle 76
Head angle 72
Wheelbase 1050
Fork trail 45
Chainstays 425
Granted, chainstays are a bit long and maybe head angle not steep enough but it's nearly there :-)
(https://weightweenies.starbike.com/forum/download/file.php?id=130801&t=1)
What frame is this?
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It's either a Mondince FM316 or one of the other open mould variants. I've got the FM326 (same frame with a 25mm longer fork) and whilst it works well for me as a gravel bike it's only tolerable with road tires fitted, to the point where I'd rather just stick with my gravel wheels (50mm Conti Terrra Trail vs GP5000 32mm) if using it on the road.
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What frame is this?
Yup, Gribs is right. fm316 but with road forks, which I guess make a bit of difference :-)
Anyhoo, sorry for straying off topic.
Fat tyres are good 8)
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Nero show was good, and echoed my current thoughts.
Still loving the 35 gp5k's - 38wam. If they come out with 40's I'll give them a go.
I don't do alpine ascents, but they are generally giving me the same or faster average on my rides, and using a gravel frame instead of previous road bike.
And it's very very comfortable!
(https://weightweenies.starbike.com/forum/download/file.php?id=131054&t=1)
What rims (internal width) do you have these tires mounted on? They look good!
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What rims (internal width) do you have these tires mounted on? They look good!
XMCS 26mm internal :)
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Okay, so I've been tinkering.
The 35mm GP5Ks have only just arrived so I don't know how they ride yet.
Observations - They are very easy to fit on a 25mm internal and feel much more secure on a 32mm internal.
To the point that regardless or ETRTO I wouldt ride them on the two 25mm internal wheel sets I have.
To date my fauoured set up is the 32mm GP5K clincher on the 32mm internal. It feel wonderful and is very secure even at 0 psi.
Hopefully the 35mm GP5Ks are even more impressive.
The GP5K 35mm were 370g each and a 32mm clincher is 290g.
Obviously the 35mm will grow as they're used - but how much ?
NOTE - all rims are hooked
(https://i.postimg.cc/zGfgcvxN/IMG-6179.jpg)
(https://i.postimg.cc/Ssc2MMx8/IMG-6180.jpg)
(https://i.postimg.cc/Wp6qpgK4/IMG-6182.jpg)
(https://i.postimg.cc/bwMsVTGC/IMG-6183.jpg)
(https://i.postimg.cc/QCXtKYPK/IMG-6186.jpg)
(https://i.postimg.cc/YqD9j3xj/IMG-6188.jpg)
(https://i.postimg.cc/FzsrHdd1/IMG-6190.jpg)
(https://i.postimg.cc/kXHJ75nC/IMG-6195.jpg)
(https://i.postimg.cc/hjMn6DyX/IMG-6196.jpg)
(https://i.postimg.cc/tCsbvHhs/IMG-6199.jpg)
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That's very interesting. This is what makes we wonder when people state tyre width X is faster/slower/more comfortable/... than tyre width Y.
There is so much variability in WAM for a certain tyre that people might be talking the same but mean something differently and vice versa.
Did you also measured tyre height?
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Okay, so I've been tinkering.
The 35mm GP5Ks have only just arrived so I don't know how they ride yet.
Observations - They are very easy to fit on a 25mm internal and feel much more secure on a 32mm internal.
To the point that regardless or ETRTO I wouldt ride them on the two 25mm internal wheel sets I have.
To date my fauoured set up is the 32mm GP5K clincher on the 32mm internal.
a 32mm nominal tire on a 32int rim is wild
Keep tinkering please
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That's very interesting. This is what makes we wonder when people state tyre width X is faster/slower/more comfortable/... than tyre width Y.
There is so much variability in WAM for a certain tyre that people might be talking the same but mean something differently and vice versa.
Did you also measured tyre height?
I knew someone would ask for the height 🤓 no, I didn’t.
I currently have the 35s on the 32int and the 32s on a 25int. I can measure those but I can’t be bothered to swap everything around again for all permutations.
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I did some math around how to estimate EW given a tire's claimed width and the rim's IW
https://weightweenies.starbike.com/forum/viewtopic.php?p=1968122
Formula is (Tire Size)*(.6708 * IW/TS + .5192)
So for POTOO....'s presented combos the estimated EWs would be:
TS IW EW
30 25 32.097
32 25 33.1188
32 32 37.8144
35 32 39.3471
35 25 34.6515
Def not perfect, Im wondering if the relationship isn't linear and I'll play with regressions some more. I think the most accurate way to figure it out would be to measure bead to bead but that obviously comes with other issues. Maybe an approximation based on IW, EW and tire height etc actually mounted and inflated. Etc. etc. But I think it's definitely possible to know what WAM a tire will have on a rim ahead of time.
And yea a 0mm gap between tire size and IW is a little crazy for me. I like to stay around 3mm or bigger.
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I’ve seen your work on WW. Well done 👍🏼
I tend to just try things rather than calculate as there seems to be so many variables involved.
The 32-32 combination was an experiment but I’m amazed at how well it performs, how well it feels and how securely the tyres are held in the rims.
Maybe not for everyone but I feel more secure ridding those than other ETRTO compliant combinations I’ve tried before.
We all make out judgements and we are all adults.
I trust my own judgement over anything else
To my eye the 30mm on a 25int looks to be the same profile/shape as a 32mm on a 32int
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If I didn't already have a pair of 32s Id be all over this for my long distance wheels. Im glad some wheel makers are finally getting with the program, but Elitewheels and a bunch of others still have 28 EW as their standard. I feel like 31-32 EW is the new minimum.
And yea I figured out a rough formula for estimating WAM from tire width and rim IW...... on the max -4 Id feel safe with (figuring 28c tires on a 24 IW rim so 31 IW for these) I wouldnt be surprised if these got to 38-39 WAM. These will really need generous frame clearances to run safely but there are def options out there. I think 32s are prob the new standard.
My EliteWheels Gravel SLR have a 45mm depth, with an EW of 34mm and IW of 24mm. And they also now have a new Gravel Aero+ wheel with a 45mm depth with an EW of 40mm and IW of 32mm (which is a real chunky boy).
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My EliteWheels Gravel SLR have a 45mm depth, with an EW of 34mm and IW of 24mm. And they also now have a new Gravel Aero+ wheel with a 45mm depth with an EW of 40mm and IW of 32mm (which is a real chunky boy).
I have seen those. I think I will still go XMCS for my next wheelsets. If Elitewheels updated their road wheels to 32-34mm EW and offered a no logo option theyd have a slam dunk budget wheelset.
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I m trying to buy a wheelset for a gravel bike i have, that can run a 35C road well (aero + safe). Have come across this rim profile from Serenade / 7tiger, 50 deep, IW 28, EW 38.
afaik, ETRTO says 35C is max 27 IW, but given they're too dumb to differentiate hooked and hookless, safety wise, i'd ride a 35C on a hooked 28 IW over a 27 IW hookless all day, every day.
And so, because a 32 IW is very far off ETRTO standards and arguably well into dangerous territory (emphasis on arguably, it's not really tested, and it's above my pay grade), this is the 1st OEM rim so far i find that can legit run a 35C with aerodynamics in mind, AND safety (at least on paper).
38 EW is narrower than i'd like by 1-2mm, but the market is very new, it's bleeding tech stuff (afaik). It just came out, it's not in the catalogue for 2026-2027, fwiw. Lead time is 30+ days.
If anyone has come across 50-60mm rims with similar features (c.28 IW, 38-40 EW), please shout.
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Im not crazy about how the rim pinches in at the bead. 28IW and 38-40EW will either require a very thick hook or a rim profile that really bulges out. XMCS has a 32.5/40 IW/EW rim that could work with arguably a better profile IMO.
https://www.xmcarbonspeed.cc/products/cs-d53cu-41-disc-brake-carbon-hooked-gravel-rims-325mm-internal-width
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Im not crazy about how the rim pinches in at the bead. 28IW and 38-40EW will either require a very thick hook or a rim profile that really bulges out. XMCS has a 32.5/40 IW/EW rim that could work with arguably a better profile IMO.
https://www.xmcarbonspeed.cc/products/cs-d53cu-41-disc-brake-carbon-hooked-gravel-rims-325mm-internal-width
There are lots of options that are 32 IW, 38-41 EW, but as per earlier in this thread, 35C w 32 IW is very far off ETRTO standards and therefore highly questionable. I'm not in love with that Serenade rim profile that caves in, but it's the best i've seen so far with these specs. I assume that if the rim doesnt cave in, you have to add a ton of material and we re all sensitive to weight.
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Is 35 on 32 IW really that bad? I have been running 28s on 24-25 IW for years and thats about as far off by ETRTO standards. I think if you're not going crazy with pressures or doing 60MPH Pogacar descents it's probably fine. Other thing I guess is the 105 rule is kind of overrated from what Ive heard, so if your 35s mount to 37s on a ~36 EW/28 IW wheel it's probably not the end of the world.
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Is 35 on 32 IW really that bad? I have been running 28s on 24-25 IW for years and thats about as far off by ETRTO standards. I think if you're not going crazy with pressures or doing 60MPH Pogacar descents it's probably fine. Other thing I guess is the 105 rule is kind of overrated from what Ive heard, so if your 35s mount to 37s on a ~36 EW/28 IW wheel it's probably not the end of the world.
The problem is that it's likely unknown. The point of the ETRTO standards is that they are the IW to which member tire manufacturers have agreed to certify their tires. Its a reference standard, not a safety testing standard. It's not that using wider widths is known to be unsafe, just that the tires weren't designed to be used on rims with IW that wide, and so the manufacturers didn't validate it.
Blowouts are one concern, but the tread cap being too small and getting flats from riding on the sidewalls are also practical concerns.
Personally, I don't mess around with this. The consequences of getting it wrong are just too high.
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The problem is that it's likely unknown. The point of the ETRTO standards is that they are the IW to which member tire manufacturers have agreed to certify their tires. Its a reference standard, not a safety testing standard. It's not that using wider widths is known to be unsafe, just that the tires weren't designed to be used on rims with IW that wide, and so the manufacturers didn't validate it.
Blowouts are one concern, but the tread cap being too small and getting flats from riding on the sidewalls are also practical concerns.
Personally, I don't mess around with this. The consequences of getting it wrong are just too high.
Good post.
By now you probably know I generally ignore ETRTO and do my own testing.
It’s interesting that the GP5K 35mm tyres I’ve recently purchased were horribly loose on two different 25mm internal hooked wheel sets I tried them with.
I did a test spin but could pop the tyres into the channel with around 15psi in the tyre, and it was extremely easy to burp them with closer to 40psi.
These are all ETRO compliant but I was extremely uncomfortable knowing people would buy these and ride them without a second thought after doing their ETRTO due diligence.
It’s a flawed process for sure. After all my 32mm tyres /rim combo shows no sidewall damage after 1500+ kilometres of hard cornering. And that’s about as far away from Compliant as you can get. ( pictures ported previously )
I’m not recommending it, but id trust these WAY more than the 35mm tyres on 25mm internals I mentioned previously.
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Cool, I added this info to the https://rubbersideup.cc/ (https://rubbersideup.cc/) database.
Wonderful resource this. rubbersideup.cc ftw.
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After learning in this thread that Pirelli 40c TLRs were not designed for 32IW wheels. I continued to ride them for about 500mi. No issues to report. My OCD kicked in and I did order Goodyear XPLR 40c road tires. Expensive, yes. Took forever to get, yes. Mounted them on my Tagoola’s tonight. Interestingly, 40c Pirellis mounted on 32IW rims measured at just over 43mm with 38psi.
Goodyears measured at exactly 40mm at the same PSI. Interested to see how they perform tomorrow.
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Welcome to the stupid world of ETRTO where the wider tyre isnt compliant, but the narrower one is 🤡
I really didn’t like the Goodyear tyres. They aren’t very fast and they need a really low pressure to be comfortable, so they’re even slower.
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Yeah, I have read that the Goodyear’s aren’t that awesome. FWIW, I have only ridden 28F, 30R tires up until this spring. Been riding a gravel frame primarily for road because the geometry works for me. Zero issues with the Pirellis. They obviously have a mild lightbulb effect but feel like my previous TLRs at 28, 30, and 32.
I am a late adopter to the wide road tire trend. Riding in the UK, roads and road surface is not predictable compared to my US/Asia riding experiences. In the future I will probably build a road bike optimized for 35-38c tires.
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You can always relegate them to winter tyres as theyll be a solid choice for that.
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Yeah, I have read that the Goodyear’s aren’t that awesome. FWIW, I have only ridden 28F, 30R tires up until this spring. Been riding a gravel frame primarily for road because the geometry works for me. Zero issues with the Pirellis. They obviously have a mild lightbulb effect but feel like my previous TLRs at 28, 30, and 32.
I am a late adopter to the wide road tire trend. Riding in the UK, roads and road surface is not predictable compared to my US/Asia riding experiences. In the future I will probably build a road bike optimized for 35-38c tires.
They are a very good tyre especially as you can get them pretty cheap. I run 30mm F1 R's at 55psi on 23mm rims and I'm 180lbs. Only tyre would change them for are the newer Pirellies because they have a much better puncture protection with slightly better RR.
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Hey!
Which Eastern frames will even fit these 35c Contis? Aero or aero tweaked? 2by or 1by?
They seems to require about 38 WAM clearance. Generally, according to ETRTO and RubberSideUp rim internal width 25-26mm will results with 37-38mm external width.
XMCS VRT, Tavelo Arden, Lightcarbon LCR018. Spect Mira maybe. What Else?
Canyon Endurace SLX 2026 ticks a lot of boxes for me but am looking for options.
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It does feel like road bikes are slowly heading that way. I'd still be a bit cautious about going outside ETRTO though—I'd rather wait until the rim manufacturers start explicitly approving those combinations.
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I just build gravel wheels for my mate with maisve XMCS rims and I had conti 35mm at home for different project so I tried to mount them on those rims. I think in the end it looks pretty cool, pretty much perfect rim tyre combination I might build something like this for myself tyre on back is conti str 32mm on 28mm internal width measures 35mm. That conti 35mm on front on 32.5mm interneal rim width measures exactly 40mm.
I tried this setup on a quick ride with and I pretty much expected to feel no difference, but I really like that feel of grip and confidence that it gives me in fast corners and I really enjoy this setup.
Iam not the best descender in the world, but with this setup I had masive smile on my face on the bottom of my biggest local technical descend :), so I think this monster road mullet setup is future for me :)