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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

#181

Post by haswell »

pmontra wrote: post #151
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…

Anecdotally my gravel bike is faster with 28 mm slick tires than with 42 mm sawtooth tires. Of course sawtooth vs slick makes a difference in friction. The hubs in the wheels could make a difference too. I use the 28 mm wheels when I go on asphalt roads in the mountains because I don't want the extra weight and friction. 42 mm for everything else.

> Anecdotally my gravel bike is faster with 28 mm slick tires than with 42 mm sawtooth tires.

Out of curiosity, do you know this to be true, or believe this to be true? I ask because the perception of speed with skinnier tires is one of the things the article touches on.

I felt similarly when I put GP5000 28mm slicks on the gravel bike, but when I looked at my ride history, I couldn’t really back that feeling of speed up with actual data, and evidence shows that at least in my case, there was no major difference between 28mm and 38mm.

(Not saying this is the case for you, but I’m just curious).

Re: Myths in cycling: wider tires are slower

#182

Post by PaulDavisThe1st »

fsckboy wrote: post #116
jcarpio wrote: post #104

Earlier quoted context omitted.

An opinion piece on the matter of being clipped in vs street shoes: https://www.rivbike.com/pages/the-shoes-ruse

the so-called "half toe clip" is the way to go. I wish I could find pedals that were clipless on one side and would let me install the half toe clip on the other (need the screw holes which usually hold the orange reflectors) for regular street shoe convenience, they are amazing and much easier to get out of than straps.

I prefer asymmetric pedal sides. I have a pair on my gravel bike that have crank bros. clips on one side, and are flat on the other. Best of both worlds!

Re: Myths in cycling: wider tires are slower

#183

Post by gnopgnip »

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)

https://www.bicyclerollingresistance.com/ compares some different tires.

Re: Myths in cycling: wider tires are slower

#184

Post by tomglynch »

germinalphrase wrote: post #146
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…

Rumor has it that a very prominent British Tour de France competitor rides a re-badged/stealth gravel bike because he finds it more comfortable.

I'm a bit hesitant to believe this. Can we have some more details?

Re: Myths in cycling: wider tires are slower

#185

Post by taneq »

dharmab wrote: post #35
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…

Similarly in the motorcycle world, dual sport and adventure models originally designed for on road/off road mix are now quite popular as commuter machines. Their long suspension makes them quite comfortable over potholes, cracks, curbs and generally poor road surfaces. And many models are narrow enough to filter between lanes with ease.

I see those dual sports all the time and I don't see the attraction other than image. They're less agile on-road which is where they spend their time. At least they're not as silly as the trend of sticking knobbly tyres on road bikes for that "scrambler" look.

If anything the opposite trend makes more sense, the motard / supermotard style where a competent off-road bike is retrofitted with road tyres and suspension tuning. They look like an absolute blast.

Re: Myths in cycling: wider tires are slower

#186

Post by usrusr »

jiscariot wrote: post #137
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…

My only complaint about the gravel trend is that at the entry (and mid) level they are often using pretty crappy disc brakes when rim brakes would have been a better choice in 90% of cases. When they are hydraulic, they are a dream to use, but with a cable you really lose the brake feel.

Rim brakes on roadbikes are awesome, but they are awesome because the calipers don't have to go far around the tire. If you try to build them for wider tires you suffer far more flex and flex means that you can't pull a high lever transmission ratio before running out of lever movement. Remember "brake boosters" on cantilever brakes? Same problem, the requirement to transfer the counterforce far around the tire. I'm a rim brake die-hard, but for anything wider than 28 go disc.

Re: Myths in cycling: wider tires are slower

#187

Post by rukuu001 »

auxym wrote: post #175
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…

In many ways, modern gravel bikes are a comeback of the "sport touring" road bikes that were popular from roughly the mid 70s to the mid 90s, then became mostly absent from market. Compared with "racing" bikes, they had wider tires, a more relaxed geometry, and various conveniences such as mounting points for fenders and racks. Thus, they were a much better option for the majority of riders who did not participate in…

Surly made a couple bike you could put fat tires on - their touring bike and a cyclocross bike. I don’t know if they’re still available but they were selling them in the mid-2000s

Re: Myths in cycling: wider tires are slower

#188

Post by nabilhat »

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)

Absolutely, Jan isn't the only one running some numbers, nor the most objective / consistent. Here are two sets of better measurements on a range of sizes of a single tire model, on the same wheel, over a range of pressures, with precise measurements of critical factors like tread depth, sidewall thickness, tread thickness, real world actual width, and actual rolling resistance measured in watts:

https://www.bicyclerollingresistance.com/specials/conti-gp40...

https://www.bicyclerollingresistance.com/specials/schwalbe-m...

So, wider tires mean you can run a comfier lower pressure at the same rolling resistance. Looking through the rest of this site, it's also super clear that there are far more significant factors to rolling resistance than width. It's practically criminal this site doesn't get tons of attention!

Re: Myths in cycling: wider tires are slower

#189

Post by usrusr »

idoubtit wrote: post #148
CalChris wrote: post #49

Earlier quoted context omitted.

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.

Cycling teams spend tens of millions each year, with Ineos going over € 50m some time ago. Are they conservative? They benchmark their material in wind tunnels. Sometimes they bend the rules with high-tech material[^1]. There's no way a team competing in Tour de France would choose fashion over performance. [^1]: https://www.theguardian.com/sport/blog/2017/jul/03/vortex-su...

And quite a bit of the money they spend comes from companies trying to sell gear to hobbyists. It's a rather wild mix between ride what makes you fast and ride to pretend that it makes you fast.

Re: Myths in cycling: wider tires are slower

#190

Post by usrusr »

scoofy wrote: post #9
mantas wrote: post #4

Earlier quoted context omitted.

They're already using wider tyres than a decade ago.

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

True. And these days, "wider is faster" is the cycling myth in need of getting corrected. Because is mostly a tie, with a very soft optimum between clearly worse extremes (neither 10 mm nor 10 inch would be fast). And people who feel in the mood for "overthrowing the old" will often do comparisons were they lower pressure on the wider tires, but don't really lower then adequately, they compare a narrow tire at the lowest and of its useable pressure range to a wider tire at the high end of its range and, surprise, with these conditions the wide one rolls easier. The assumed optimum has shifted, but it hasn't run away.
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