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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

#41

Post by wizzwizz4 »

at-fates-hands wrote: post #29
scoofy wrote: post #9

Earlier quoted context omitted.

Yes. Much, much wider. I nearly passed by this comments section because i assumed everyone already knew this was true.

I think you're exaggerating a bit. From 2018: https://www.businessinsider.com/tour-de-france-wider-tires-l... "It depends on the road surface, but 10 years ago the standard was 23mm tires at 8 or 8.5 bar, or 115, 120 psi," Brown said. "And now it's 25mm for regular road racing and 7 to 7.5 bar for front and rear, so a little less than 100 to 110 max on the bikes." 2mm and 10psi less is not that huge a difference.

8% width and 13% pressure is significant.

Re: Myths in cycling: wider tires are slower

#42

Post by kazinator »

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.

First order effects are the only effects which matter in cycling. This isn't aerospace.

Racing slicks are a different material.

In Formula 1 racing, you go through multiple tires in one race.

In consumer driving, tires are expected to last 100,000 km or more.

There is even the practice, in racing, of using chemicals to attack the rubber to soften it.

Re: Myths in cycling: wider tires are slower

#43

Post by outside1234 »

periheli0n wrote: post #17
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?

The problem is that wide tyres tend to eat lots of momentum in corners. When going mainly straight and/or on uneven ground, use wide tyres. When cornering a lot, use narrow tyres.

Also, they have higher raw weight, so thinner is better uphill.

Re: Myths in cycling: wider tires are slower

#44

Post by kazinator »

wizzwizz4 wrote: post #37
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…

> The coefficient of friction is a constant which depends on the materials. This is an approximation. It holds here, but it doesn't hold for (say) figure skates on road.

That is false; you might be thinking of figure skates on ice. Steel on road obeys coefficient of friction.

(I promise I will keep that in mind the next time I attach skates to a bicycle frame.)

Re: Myths in cycling: wider tires are slower

#45

Post by gameswithgo »

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?

Tour De France riders do use wider tires than they used to these days. At some point the width starts imparting aerodynamic drag penalties that are worse than the handling gains.

Re: Myths in cycling: wider tires are slower

#46

Post by CalChris »

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…

Slicks themselves are under-appreciated.

Re: Myths in cycling: wider tires are slower

#48

Post by jaypeg25 »

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 bought a Specialized Diverge over a year ago. It was mostly to commute to and from work, but also to have the ability to take gravel paths and trails on the weekends. It's been awesome but friends have suggested I take off the stock tires and add some new ones. Is it really worth it? The tires are already fairly fat already, at least compared to road bike tires.

Re: Myths in cycling: wider tires are slower

#49

Post by CalChris »

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.

Re: Myths in cycling: wider tires are slower

#50

Post by wolverine876 »

durkie wrote: post #27

wider tires also let you run lower pressures, which puts you more in the comfort zone of being able to convert to tubeless. not every rim/tire combination works with tubeless, but if you are able to pull it off, it's among my personal top 5 list of cycling innovations of the past 30 years.

I'm missing something: How do lower pressures lead to tubeless?
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