7 ms·

Myths in Cycling (1): Wider Tires Are Slower (2018)

50 points by tokai 7y ago

caseyf7 7y ago
Makes gravel bikes even more attractive.
jl2718 7y ago
This is not a new theoretical result, but it is a new practical reality. Tires are built differently today due to better materials like multi-layer puncture-resistant weaves. It used to be a thick layer of rubber in the middle and relatively weak sidewalls, so the contact profile would be nearly cylindrical. Lower pressures were awful, and the sidewalls would blow out on a bigger tire above 60psi. There are a few other differences that matter a lot in the peloton. Power transfer is important for holding a tight draft. A pro on 28s will definitely notice a delayed/muted impulse response over 23s. I believe this also affects pedaling efficiency, as any MTB racer on a soft tail will attest. Narrow tires also give much better handling/braking and therefore much faster descents. Fat tires braking gives this weird kick-back that feels like it’s tossing you over. Still, I ride fatties. I love the way they smooth out the road. But they’re not necessarily faster.
- tokai 7y ago
  The width is crawling upwards for the pro riders. No sub 25mm tire was used in the Tour de France the last two years, iirc. I can't see them going over 30mm though. The article underplays aerodynamics in my opinion.
  - SkyMarshal 7y ago
    Any idea if pro riders increasing their tire size is associated with them also transitioning to disk brakes? Disks solve at least half the problem - braking. (Narrow tires may still handle better in other ways though).
    - tokai 7y ago
      Yeah, disk breaks are definitely helping the trend. From the head mechanic of EF Education last year: «The disc-brake thing has gained real momentum, so on those frames you can certainly run wider tires because there's the clearance for it. I could see it evolving to 26mm or 27 mm as the standard road-racing tire, sure. Why not.» https://www.businessinsider.com/tour-de-france-wider-tires-lower-pressure-faster-2018-7?r=US&IR=T https://www.businessinsider.com/tour-de-france-wider-tires-l...
- frabbit 7y ago
  contact profile would be nearly cylindrical How would a 2-dimensional contact profile be describable with a 3-dimensional object? A pro on 28s will definitely notice a delayed/muted impulse response over 23s. Really? Is this a measured, observable fact or another piece of woo that cyclists have believed for donkeys' years? I believe this also affects pedaling efficiency, as any MTB racer on a soft tail will attest. Are you seriously claiming that bouncing up and down on a rear-suspended MTB is comparable to riding on a 622-28 inflated to 620kPa ? Narrow tires also give much better handling/braking and therefore much faster descents. Fat tires braking gives this weird kick-back that feels like it’s tossing you over. Again, I have to ask for specifics and measurements. I will counter-claim that that the inferior response of over-inflated narrow tires to road imperfections leads to much more jittery descents and inferior handling on most surfaces, ths leading to slower descents (that's what all the Bicycle Quarterly tests of roll-downs are about).
- _Wintermute 7y ago
  As a competitive cyclist and someone who spends far too much time thinking and talking about bikes, I've never heard any of these claims, and in fact most of them are the opposite of the common consensus among cyclists.
gyuserbti 7y ago
Surprised clipless pedals aren't included in the list of myths. These sorts of myths exist in many sports; I am fascinated by them.
- TheSpiceIsLife 7y ago
  What's the myth with clipless pedals?
  - AtlasBarfed 7y ago
    Compared to cages where you're so tightened in you lose feeling in your feet? Triathletes would have switched to cages years ago if this was a myth.
  - mikekchar 7y ago
    I suspect OP is referring to the idea that you can get significant power returns on the upstroke with clipless pedals. This is definitely questionable. However clipless pedals are still a good idea because your feet don't slide off the pedals. Especially in wet weather they are dramatically safer than flat pedals.
    - tonyedgecombe 7y ago
      Safer until you forget to unclip at a stop.
      - rubbingalcohol 7y ago
        After the second time you forget, you'll never forget again.
        tonyedgecombe 7y ago
        It's like picking the soldering iron up by the wrong end, I watched both of my kids do that. Once.
    - 7y ago
bjourne 7y ago
> The UCI requires a minimum wheel size of 55 cm, yet racers use 700C wheels that are 10 cm larger than required. If wheel weight mattered as much as most cyclists imagine, then pros using the smallest wheels would win every race. And yet, even though many have tried smaller wheels, all have returned to 700C wheels – probably because the larger wheels handle better due to their optimized rotational inertia. (But that is a topic for another post.) I know this! The answer is because the neutral van only carries 700c wheels. If a rider gets a flat the wheel needs to be replaced quickly thus it's advantageous to use the most common wheel type. It is explained in this video by a professional cyclist: https://www.youtube.com/watch?v=jLnwR0ZxhcI https://www.youtube.com/watch?v=jLnwR0ZxhcI Wider tires are discussed in this video (also by GCN): https://www.youtube.com/watch?v=yrHxQg1OW0A https://www.youtube.com/watch?v=yrHxQg1OW0A They also find that wider tires are slightly faster. Although they discuss widths of 23 vs 25 or 28 mm which seem like a minor difference for most cyclists. But probably makes a world of difference for professionals.
rwmj 7y ago
Since there's a placebo effect mentioned in the article, I wonder if they double-blinded the tests? They don't say if they did, and it would be hard to do.
fulafel 7y ago
I think the most common myth is that you should get an athletic bike if you want to get into bicycling.
unicornporn 7y ago
Although I, since a couple of years, ride (and preach) 50mm tires I believe it should be mentioned that Jan Heine's writings aren't exactly independent and objective research. He makes his money selling (mostly) wide and supple tires (Rene Herse, formerly Compass). They're not always as superior[1] as he likes to point out. If you want to try wider tires (and your frame can fit them) there are alternatives to (the expensive) Compass tires. Try Maxxis DTH for 26" wheels and Torch for 28". Panaracer makes a bunch of supple and wide models. Pacenti Pari-Moto (made by Panaracer) nice and cheap. Also have a look at Schwalbe G-One Speed (available in a wide selection of sizes). Maxxis are cheaper in the US, Schwalbe are cheaper in Europe. [1] https://www.bicyclerollingresistance.com/tour-reviews/compass-bon-jon-pass-2018 https://www.bicyclerollingresistance.com/tour-reviews/compas...
teslaberry 7y ago
Heavier tires and wheels Re most certainly slower at normal speeds below 20mph in a routine stop and go environment like typical urban cycling. But the real wisdom is about keping your tires overinflated if u eant whichever bike you hapoen ti have to br easiest. 90% of cyclists routinely ride unintentionally underinflated tires.

50 points by tokai 7y ago

Makes gravel bikes even more attractive.

This is not a new theoretical result, but it is a new practical reality. Tires are built differently today due to better materials like multi-layer puncture-resistant weaves. It used to be a thick layer of rubber in the middle and relatively weak sidewalls, so the contact profile would be nearly cylindrical. Lower pressures were awful, and the sidewalls would blow out on a bigger tire above 60psi. There are a few other differences that matter a lot in the peloton. Power transfer is important for holding a tight draft. A pro on 28s will definitely notice a delayed/muted impulse response over 23s. I believe this also affects pedaling efficiency, as any MTB racer on a soft tail will attest. Narrow tires also give much better handling/braking and therefore much faster descents. Fat tires braking gives this weird kick-back that feels like it’s tossing you over. Still, I ride fatties. I love the way they smooth out the road. But they’re not necessarily faster.

tokai 7y ago
The width is crawling upwards for the pro riders. No sub 25mm tire was used in the Tour de France the last two years, iirc. I can't see them going over 30mm though. The article underplays aerodynamics in my opinion.
- SkyMarshal 7y ago
  Any idea if pro riders increasing their tire size is associated with them also transitioning to disk brakes? Disks solve at least half the problem - braking. (Narrow tires may still handle better in other ways though).
  - tokai 7y ago
    Yeah, disk breaks are definitely helping the trend. From the head mechanic of EF Education last year: «The disc-brake thing has gained real momentum, so on those frames you can certainly run wider tires because there's the clearance for it. I could see it evolving to 26mm or 27 mm as the standard road-racing tire, sure. Why not.» https://www.businessinsider.com/tour-de-france-wider-tires-lower-pressure-faster-2018-7?r=US&IR=T https://www.businessinsider.com/tour-de-france-wider-tires-l...
frabbit 7y ago
contact profile would be nearly cylindrical How would a 2-dimensional contact profile be describable with a 3-dimensional object? A pro on 28s will definitely notice a delayed/muted impulse response over 23s. Really? Is this a measured, observable fact or another piece of woo that cyclists have believed for donkeys' years? I believe this also affects pedaling efficiency, as any MTB racer on a soft tail will attest. Are you seriously claiming that bouncing up and down on a rear-suspended MTB is comparable to riding on a 622-28 inflated to 620kPa ? Narrow tires also give much better handling/braking and therefore much faster descents. Fat tires braking gives this weird kick-back that feels like it’s tossing you over. Again, I have to ask for specifics and measurements. I will counter-claim that that the inferior response of over-inflated narrow tires to road imperfections leads to much more jittery descents and inferior handling on most surfaces, ths leading to slower descents (that's what all the Bicycle Quarterly tests of roll-downs are about).
_Wintermute 7y ago
As a competitive cyclist and someone who spends far too much time thinking and talking about bikes, I've never heard any of these claims, and in fact most of them are the opposite of the common consensus among cyclists.

gyuserbti 7y ago

Surprised clipless pedals aren't included in the list of myths. These sorts of myths exist in many sports; I am fascinated by them.

TheSpiceIsLife 7y ago
What's the myth with clipless pedals?
- AtlasBarfed 7y ago
  Compared to cages where you're so tightened in you lose feeling in your feet? Triathletes would have switched to cages years ago if this was a myth.
- mikekchar 7y ago
  I suspect OP is referring to the idea that you can get significant power returns on the upstroke with clipless pedals. This is definitely questionable. However clipless pedals are still a good idea because your feet don't slide off the pedals. Especially in wet weather they are dramatically safer than flat pedals.
  - tonyedgecombe 7y ago
    Safer until you forget to unclip at a stop.
    - rubbingalcohol 7y ago
      After the second time you forget, you'll never forget again.
      - tonyedgecombe 7y ago
        It's like picking the soldering iron up by the wrong end, I watched both of my kids do that. Once.
  - 7y ago

bjourne 7y ago

> The UCI requires a minimum wheel size of 55 cm, yet racers use 700C wheels that are 10 cm larger than required. If wheel weight mattered as much as most cyclists imagine, then pros using the smallest wheels would win every race. And yet, even though many have tried smaller wheels, all have returned to 700C wheels – probably because the larger wheels handle better due to their optimized rotational inertia. (But that is a topic for another post.) I know this! The answer is because the neutral van only carries 700c wheels. If a rider gets a flat the wheel needs to be replaced quickly thus it's advantageous to use the most common wheel type. It is explained in this video by a professional cyclist: https://www.youtube.com/watch?v=jLnwR0ZxhcI https://www.youtube.com/watch?v=jLnwR0ZxhcI Wider tires are discussed in this video (also by GCN): https://www.youtube.com/watch?v=yrHxQg1OW0A https://www.youtube.com/watch?v=yrHxQg1OW0A They also find that wider tires are slightly faster. Although they discuss widths of 23 vs 25 or 28 mm which seem like a minor difference for most cyclists. But probably makes a world of difference for professionals.

rwmj 7y ago

Since there's a placebo effect mentioned in the article, I wonder if they double-blinded the tests? They don't say if they did, and it would be hard to do.

fulafel 7y ago

I think the most common myth is that you should get an athletic bike if you want to get into bicycling.

unicornporn 7y ago

Although I, since a couple of years, ride (and preach) 50mm tires I believe it should be mentioned that Jan Heine's writings aren't exactly independent and objective research. He makes his money selling (mostly) wide and supple tires (Rene Herse, formerly Compass). They're not always as superior[1] as he likes to point out. If you want to try wider tires (and your frame can fit them) there are alternatives to (the expensive) Compass tires. Try Maxxis DTH for 26" wheels and Torch for 28". Panaracer makes a bunch of supple and wide models. Pacenti Pari-Moto (made by Panaracer) nice and cheap. Also have a look at Schwalbe G-One Speed (available in a wide selection of sizes). Maxxis are cheaper in the US, Schwalbe are cheaper in Europe. [1] https://www.bicyclerollingresistance.com/tour-reviews/compass-bon-jon-pass-2018 https://www.bicyclerollingresistance.com/tour-reviews/compas...

teslaberry 7y ago

Heavier tires and wheels Re most certainly slower at normal speeds below 20mph in a routine stop and go environment like typical urban cycling. But the real wisdom is about keping your tires overinflated if u eant whichever bike you hapoen ti have to br easiest. 90% of cyclists routinely ride unintentionally underinflated tires.