[Closed] Wider tyres are faster. Apparently.

Fat bike on the local 10 mile time trial then!

Fat bike on the local 10 mile time trial then!

If you find a fatty tyre thats the same compound, thickness and tpi as a top end road tyre, and youre willing to take the aero hit, then go for it.

I’ve just noticed this is an old article, so has probably been discussed before.

It has, for many years, but people who believe that skinny tyres at high pressure roll faster won't believe it no matter what. What works on a very smooth road doesn't apply to off-road conditions. Plus, the main thing that roadies care about is aero drag, not rolling resistance, that's the major benefit of skinny tyres.

The guy that did the GB Divide on a fat bike made me think of it. He was pretty speedy too and did it in a very respectable time.

Supernova….let’s try to reword that headline….

Company who make wide tyres say wide tyres are faster….
This article gets trotted out every now and then.

I use Renee Herse (formerly compass) and they do make nice tyres. However they are not the fastest…..it’s not even close to be honest. Especially when I take into account the amount of flats I get using those tyres!!
I’ll still use Renee Herse tyres as they are very comfortable. But quick….well, not particularly.

I think part of the problem is that fast is such an open statement. I race crits (or did pre-Covid), there is a absolutely no way on a nice smooth crit circuit that a 38mm tyres is going to be faster than a 25 (actually a 23mm is fastest on my set up). So on a rough road, performing a simple roll down test, I could well believe that a 38mm tyre will be faster than for example my 25mm tyre.
But over the course of a road race, with short sharp uphills, fast downhill sprints, sprinting out of every corner….then no. I’ll stick to my 23’s or 25’s.

A couple of us on here who race on the road have performed our own testing to maximise our own equipment. All power meter based, mine was around a closed off crit circuit, good mixture of corners, hill and fast long high power / high speed section. The fastest combination for me was 60mm wheel with a 23mm front tyre.
I don’t use that combination for out and about on my road bike though, I use 40mm wheel and 30mm tyre. For me that’s absolutely optimal…..actually 55mm deep and 27mm tyres is ideal for the road on my set up, but I’m a bit of a tart and think my 40mm wheels look better on my bike!
The widest tyre I tested was a 32mm tyre. I think the best way to say it is, would I take 23mm tyre on my road bike on the SDW? Nope. Would I take 38mm tyres on my road bike on the SDW, yep and have done.
What would be fastest on the SDW? The 38mm tyre.

ETA: I’ve just noticed this is an old article, so has probably been discussed before.

It has, for many years, but people who believe that skinny tyres at high pressure roll faster won’t believe it no matter what.

Skinny tyres at high pressure feel faster which is why people struggle with it. They spin up faster, the front feels like it turns faster and overall they just feel faster.
On an average road they will be slower but still feel faster and the speed differences are too minimal to feel above how the bike feels.

There is clearly a tipping point though as a 5 inch wide tyre is never going to be as quick as a comparable 28c tyre on a smoothish road.

Mind the Fat bike tyres in the Forest Of Dean were much faster through the mud than people with skinny tyres they were all over place.

I've never understood the idea that skinny mtb tyres 'cut through' the mud - I'm always happier on a pair of 2.8s in winter.

I’ve got a cross race in a couple of weekends time and will be taking a single speed with 2.8s on.

Expecting top ten based on the above!

yeah, I remember reading a Schwalbe study almost 10 years ago which came to this conclusion

+1

Maybe this one: This is all google found

https://www.schwalbetires.com/wider_faster_page

It is difficult to compare like with like.

I've never seen a 2" tyre built to the same spec as a 28mm 'fast' tyre, there's far thicker sidewalls, coarser tread etc. I suspect that is where the drag comes from.

I would say outright speed is more to do with the entire system. Rider, bike, wheel, tyre. For example, on my set up for a 1 hour crit my aero bike with the 23mm tyre is ideal. For a 3 hour road race on rough back roads, then a 28 or a 30mm with my newer wider rims could be faster.

ZIPP have a white paper discussing the wheel system. Wider lower pressure is their conclusion, but that is based on a new wider rim. Their testing is conducted with a 28mm tyre.

Doesn’t Renee Herse also say that 28mm was no faster (or slower) than a wider tyre on his roll down tests?

I’ve never understood the idea that skinny mtb tyres ‘cut through’ the mud – I’m always happier on a pair of 2.8s in winter.

Someone on this very forum suggested not that long ago that using any tyre over 2.5 was a kind of 'willy waving'.

No, I don't get it either.

Company who make wide tyres say wide tyres are faster

Everyone says they are faster - because they are (generally). Well, on road. And by wide I mean 28c rather than 23c. Anecdotally, having just moved from a bike that could only take 23c to one that has 28s, this would seem to be the case.

Molgrips, they’re not though.
There’s so much more to speed on a road bike than just tyre size. On my aero bike a 28mm front tyre on a smooth crit circuit is not faster than a 23mm tyre.
I do agree that generally 28mm on a wider modern rim would be faster for normal road use. But to say tyres in the 38mm to 54mm range are equally fast is incorrect. This is what Renee Herse is purporting. They are equally fast for a given scenario, which does not equate to equally fast overall.
We are all familiar with the term marginal gains….how many of those in the pro peloton ride 32mm tyres for general road racing?
Maybe Some of the classics they might do. But for normal roads, 28mm max. Do you think sprinters would want to have a 44mm tyre? What about city crits, every corner is a 1000 watt effort for 15 seconds, would you want a 44mm tyre?

Do you think sprinters would want to have a 44mm tyre? What about city crits, every corner is a 1000 watt effort for 15 seconds, would you want a 44mm tyre?

Jan Heine from the link above is more about Paris-Brest-Paris, a 1200km non stop endurance race, crits and sprints are quite far from his use case.

Fat bike on the local 10 mile time trial then!

I did, on a hillclimb (it's barely a hill, it's a 1km slope, with a ramp in the middle and the last 1/3 is flat). I wasn't last.

I would have been quicker on a road bike though.

@ ayjaydoubleyou, completely agree. But it’s the headline and actually even the wording in the paper that I think is worded as an advertorial.
Whilst he’s likely correct in the scenario you mention, to say wide tyres are faster is incorrect.
It’s faster in a certain scenario, but overall as a road racing tyre, given optimal systems, then no, it’s not faster.

Molgrips, they’re not though.
There’s so much more to speed on a road bike than just tyre size. On my aero bike a 28mm front tyre on a smooth crit circuit is not faster than a 23mm tyre.

I am surprised you can be so sure.

The differences for a decent tyre are probably a few watts between two tyres which you're not going to measure on a power meter in an actual event as there are just too many other variables.

There’s so much more to speed on a road bike than just tyre size.

Obviously, but I was only talking about tyres.

I do agree that generally 28mm on a wider modern rim would be faster for normal road use.

We agree then. As I said, 'wider' tyres means more than 23c because that's what used to be standard. And the pro peleton have indeed upsized their tyres. It's a statement meant to be taken in context, not in an abstract sense. Otherwise a tyre two miles wide would be able to travel at near the speed of light.

Yeah all my posts have agreed that 23mm is
not as fast as a 28mm on a modern wider rim.
But the article states that 38mm to 54mm is just as fast. This is what I take exception to as it’s only as fast in a given scenario.
I even gave two different scenarios. For crit racing on my system 23mm tyres appear to be the fastest. Again, this is one of the reasons TT bikes have a 23mm tyre. For crit racing narrow also has the benefit of being more “flickabke”, especially compared to the 38mm Rene Herse tyres I have on my bike currently.
But for riding the SDW, I would be faster on a completely different setup. My Renee Herse 38mm tyres would be faster than my road racing tyre. A 54mm tyre could be faster than the 38mm tyre.

As I’ve said, my only point I’m making is the generalisation in the article that 38-54mm tyres are as fast as 28mm. They are as fast in a given scenario. Slower in out and out speed scenarios.

Footflaps, you’re absolutely correct, I’m not 100% certain. However my methodology was pretty similar to the same used by Jan Herse in the article.
In the scenario he tested, his wider tyres were equally as fast at rolling down a hill as 28mm tyres. My testing was equally unscientific and showed there are differences between setups, I was actually trying to maintain an average speed over 5 laps of a circuit. I didn’t always use the same tyre compound. But I did Use the same wheel, apart from some tests using a completely different bike - but that was to look at the speed difference of that setup. My testing was about what worked best for me. I wasn’t trying to sell anything. Only maximising what is best is a given race day setup for the type of events I take part in.

Jeff Jones has said this for years.

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supernova
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I’ve never understood the idea that skinny mtb tyres ‘cut through’ the mud – I’m always happier on a pair of 2.8s in winter.

If it’s only a couple of inches of mud on top of, say, a stoney forest road then maybe the narrow tyres would be better than skating around on top of the mud on wider tyres. Maybe...
However in real mud and very soft conditions what is the tyre supposed to “cut through” to, when everything is just peat bog (or it is around here atm...).

But the article states that 38mm to 54mm is just as fast.

Well I didn't read the actual article of course, what do you expect this is the internet 🙂

Where do you do crit racing btw? It sounds fun.

Hi Molgrips. As always on the internet everyone is in agreement but arguing anyway!!
I’m really fortunate from a racing perspective, I’m in Milton Keynes, we have a closed circuit here (MK Bowl), I raced here a lot, but equally important is that the circuit is available one evening a week for general riding / testing / training.
As I’ve got older I’m less inclined to travel too far to get my ass handed to me by a load of youngsters, so now focusing on Vets racing…..or will be from April/May depending on what COVID does over Winter.
The bowl is pretty good for testing, short hill, fast descent and a fast straight, then repeat. It also has two race configurations, inner kidney shaped bowl and the slightly larger outer sections. The outer sections is where things get spicey and the race can get broken up. Right hand corner, mini sprint, left hand corner sprint, left hand corner uphill. FTP is pretty irrelevant, it’s how fast you can recover from the multiple intense bursts…..gets a lot harder as I’ve gotten older!

I always feel like I’m anti Rene Herse or compass tyres, and I’m not. I use them and think they’re really good tyres. I just don’t agree with the wording in the article.

I skimmed the article. Far to little data. If they did the power meter test at 10mph they'll get a different result to 20mph. The % of the power needed to overcome air resistance increases with speed.

Is it just me, they don't mention what they did with pressure. This article is excellent on pressure. In short pumping a 23mm tyre to the same pressure as a 28mm tyre makes no sense. This gives the wider tyre less rolling resistance but also makes it less comfortable than the 23mm tyre. The conclusion is that if you adjust the pressure to make all tyres flex by the same amount under a static load then all widths have the same rolling resistance on smooth roads. A slow rider like me on poor roads benefits from wider tyres. So I run 35mm tyres for road work on my gravel bike

https://www.bicyclerollingresistance.com/specials/grand-prix-5000-comparison

This old shit again. At least ampthill has got the key link in play.

Wider tyres CAN be faster, but are often not.

1) Aerodynamic loss and additional weight can individually and sum to overcome any benefit gained by reducing hysteresis.

2) Wider tyres (in a lab) have lower rolling resistances than narrower tyres at identical pressures. But a 32c @ 90psi is not more comfortable than a 25c @ 90psi, but less. At equal levels of comfort and grip (Measured by tyre drop), wider tyres stop being faster.

3) Wider tyres have a different shaped contact patch at the same tyre drop. Generally, they are shorter and fatter. This gives an improvement in braking grip and straight-line traction.

4) Wider tyres are faster in scenarios where you are distributing pressure and so sinking into soft surfaces less. Think narrow Vs wide skis in powder.

5) Wider tyres have better physical structure and handle torsional loads better at low pressures (and low pressures improve grip). This is the main reason we enjoy them on our mountain bikes, because unless racing grip usually beats rolling resistance.

In short: you're usually slower if you go above 25c on your road bike, 37c on your gravel bike, or 2.6 on your mountain bike (unless you're riding on snow or sand)

@supernova @thisisnotaspoon

https://www.instagram.com/substandard8/p/Bx0UFmRlEoo/?utm_medium=copy_link

I was being a bit flippant with my comment safe in the knowledge that local legend Andy Deacon of the inaugural GBDuro had done it, 26:05.

Over the course of GBDuro he commented that the advantage of the extra cushioning aided him greatly off road saving fatigue build up. He did however need to swap his tyres round due to wear on the rear. Just don't mention that crank...