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Myths in cycling: wider tires are slower

renehersecycles.com

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Re: Myths in cycling: wider tires are slower

#61

Post by jasonvorhe »

haswell wrote: post #12

This is one of the reasons I love the emergence of the "Gravel" category of bikes. They look and have geometry similar to a road bike, but they have enough clearance for nice fat gravel tires. I ride in Chicago (shitty roads, potholes & construction are everywhere), and love that I can put nice 38mm+ GravelKing Slick tires on the bike, and still have no problem keeping up with most road bikes. I've gotten funny looks…

I got my Cannondale CAADX in 2015 right before the gravel hype started. I've put WTB Riddler 37 on it and it's close to a gravel bike but a bit more direct and maneuverable - I love it. If I was in for a new bike right now, I'd be very tempted to get a Canyon Grail with electronic shifting though. After Cannondale's manufacturing error put me in the hospital for a night followed by a broad recall of a lot of their carbon fiber forks and they new minimalist logo I'm just not a fan of Cannondale anymore. But the Topstone is a great bike!

Re: Myths in cycling: wider tires are slower

#62

Post by kazinator »

CalChris wrote: post #21

Narrow tires also require higher pressure with a less comfortable ride. Bigger riders, Clydesdales, require more pressure. These rock hard tire inflations are then more prone to snake bite flats. As the discussion section in the article points out, wider tires used to be common. I think we're rediscovering why.

Snake bite flats are precisely from low pressure. The term comes from two punctures that come from the rim pinching the tire, which is due to inadequate pressure to absorb an impact.

Rock hard tire inflations are prone to failure from the pressure itself.

Re: Myths in cycling: wider tires are slower

#63

Post by twoWhlsGud »

carl_dr wrote: post #7

I’ve ridden 25mm to 32mm tyres on the same bike, in the same season, and my (absolutely amateur, I’m 250lb and did 125 miles at 16mph) experience is that 32mm tyres are no slower, but are significantly more comfortable, and allow me to ride significantly longer with less fatigue. Does anyone else have any other data points?

This is all anecdotal, but a couple of decades ago I was riding road bikes with standard 622 rims shod with 23 mm tires. In the 2000s I shifted to riding road bikes with 584 rims and 42mm tires because they were frankly just more fun for me (lower pressure = greater comfort and better suspension meant better handling on our rough Northwest roads). The outer diameter was about the same, so I didn’t have to do something weird with the geometry of the bikes.

When Jan came out with 55mm super-supple tires on 559 rims (again that would keep the outer diameter the same) I thought what the heck and got Seven Cycles to build me a custom around the new tires. Now that road bikes run disk brakes, you can run multiple rim size on the same frame so I figured I could always go back to 584/42mm if I didn’t like the crazy wide tires. (I was worried enough that I actually got somebody to build me a new set of 584 rims for the new frame.)

I’ve had that bike for about 3 years now and have ridden several thousand miles on it. Only a few tens of those miles have been on the fancy 584 rims with the (equally nice) 42mm tires – the 55mm tires are even more fun than the 42's were for me. If you ride on mixed surfaces, the extra suspension you get from running low pressures (I run around 26 PSI front/32 back) makes a big difference (or at least it does for me) - both in handling and comfort.

Downsides are increased weight (the 55mm tires weigh about 420 g a piece which is impressively light given the amount of material, but still a lot heavier than those old 622/23 mm tires back in the day) and the increased maintenance of running them tubeless (though of course you can run them with tubes-though given that I haven’t had a flat in 3 years and I’m riding on Seattle streets, I’ll put up with having to monitor the sealant levels every month or so).

Re: Myths in cycling: wider tires are slower

#64

Post by mumblemumble »

salty_biscuits wrote: post #55
soperj wrote: post #5

Another one is that clip in pedals make you faster.

No data other than anecdotal but totally agree. I use flats on my road bike and look like an idiot but I go just as fast. I prefer to be able to wear normal shoes so I have less to carry. The whole "you can push while you pull" thing makes no sense, my quads are way more powerful than my hamstrings and you never need that much force when pedalling anyway, cardio fitness is always the limiting factor for me, not leg s…

"You can push while you pull" never made much sense to me on the road. Because, you're right, those muscles aren't as efficient, so you're just going to have to pay the expenditure back with interest.

But, off-road, it can occasionally be useful to give 'er one or two extra firm strokes to help power over a small rise or whatever.

Re: Myths in cycling: wider tires are slower

#65

Post by kazinator »

haswell wrote: post #19
carl_dr wrote: post #7

I’ve ridden 25mm to 32mm tyres on the same bike, in the same season, and my (absolutely amateur, I’m 250lb and did 125 miles at 16mph) experience is that 32mm tyres are no slower, but are significantly more comfortable, and allow me to ride significantly longer with less fatigue. Does anyone else have any other data points?

I've spent a lot of time with 28mm tires, but I'm absolutely in love with my 38mm GravelKing slicks. I don't really notice much speed difference (if any), and the comfort level makes up for it if there is. I ride for fitness, so I'm happy. More details in my other comment (I actually ride a gravel bike so I have the extra clearance for big fat tires if I need).

The comfort level you feel is also a form of efficiency that makes you faster. Vibration absorbs energy and saps your momentum.

Re: Myths in cycling: wider tires are slower

#66

Post by brianwawok »

TheAlchemist wrote: post #58

Is the data available somewhere ? It doesn’t match my experience at all. I have a road bike and a gravel bike - same quality range (gravel slightly higher). At low speeds, that may be true - the difference is negligible. But at higher speeds / power outputs, the road bike beats the gravel hands down - by a significant margin (big enough to be felt, without a power meter)

Does your gravel bike have road slicks? Is your geometry the same, i.e. your reach and drop is the same?

Re: Myths in cycling: wider tires are slower

#67

Post by carl_dr »

CalChris wrote: post #49
louthy wrote: post #2

If that were the case, surely Tour de France riders would use wider tyres to gain more grip going around corners, especially in time-trials or stages with sprint finishes. Doesn’t a greater surface area touching the floor means more frictional effects when pushing against the road?

You can't really rely on the Tour de France peloton for guidance. They're pretty conservative and, to a degree, ruled by fashion and sponsors.

I guarantee the masters of marginal gains, Sky (now Ineos Grenadiers), will have spent some resources on looking at which tyres are actually faster for them, regardless of fashion or sponsors.

I think it’s safe to say that whatever they ride on are the fastest options - and every other team would follow - or that within a certain set of parameters, it doesn’t matter.

I just tried to search to see if Ineos run different tyres on different race and stages, and found nothing conclusive.

Re: Myths in cycling: wider tires are slower

#68

Post by soperj »

caturopath wrote: post #22
soperj wrote: post #5

Another one is that clip in pedals make you faster.

Compared to cages or straps, you mean? This is shockingly unintuitive if you mean compared to flats. The theory is that the force you use pulling up will always have a reduction in the force you use pushing down?

Compared to flats! I also couldn't believe it at first. I'm not sure the theory of it, but I've done long rides with people in both (80+km) and there was no difference in speed. I also would do a 16km route as fast as I could, and there was no discernible difference in avg speed or time.

Re: Myths in cycling: wider tires are slower

#69

Post by [deleted] »

Retric wrote: post #32
kazinator wrote: post #6

Earlier quoted context omitted.

Regardless of whether it is the case or not, Tour de France riders would not use wider tires to gain more grip around corners because ... wider tires do not add more grip. You get a larger contact patch from a wider tire, but that patch has less pressure. Grip (static friction) is coefficient of friction, times weight. The coefficient of friction is a constant which depends on the materials. Rubber on road is no exce…

That’s the first order effects, however substances deform under pressure which is just one of many complexities involved. For car tires on dry pavement you get maximum grip from racing slicks. Unfortunately they need to swap in the rain.

[deleted]

Re: Myths in cycling: wider tires are slower

#70

Post by kazinator »

twoWhlsGud wrote: post #63
carl_dr wrote: post #7

I’ve ridden 25mm to 32mm tyres on the same bike, in the same season, and my (absolutely amateur, I’m 250lb and did 125 miles at 16mph) experience is that 32mm tyres are no slower, but are significantly more comfortable, and allow me to ride significantly longer with less fatigue. Does anyone else have any other data points?

This is all anecdotal, but a couple of decades ago I was riding road bikes with standard 622 rims shod with 23 mm tires. In the 2000s I shifted to riding road bikes with 584 rims and 42mm tires because they were frankly just more fun for me (lower pressure = greater comfort and better suspension meant better handling on our rough Northwest roads). The outer diameter was about the same, so I didn’t have to do somethin…

I suspect that 42mm is already into diminishing returns for road cycling.
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