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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

#371

Post by jmilloy »

discreteevent wrote: post #315
sliken wrote: post #284

Earlier quoted context omitted.

Heh, rene makes a business out of being different, and has some good ideas, but they do push it to far sometimes. Sure I get it, a stoppie shows that the brakes are not a bottleneck, it's the traction. So sure, sometimes, on some bikes, with some riders, under some conditions you get perfect braking. However in the real world there's various rim surfaces (aluminum, steel, carbon fiber), with a variation of water, gri…

Agreed on everything except the road racers. Maybe some want discs but the pros don't. Discs are more likely to rub for them because pro cyclists generate enough power to twist the wheel. If you are trying to gain seconds over a few hours then the sound of rubbing must be torture. Chris Froome spoke out about it recently. Team Ineos just won the Giro and they don't use rim brakes because their sponsor does not oblige…

This is something that I think a lot of people at overlooking even they reference pro racing: they ride the bikes their sponsors make them ride. And the sponsors have incentives that are not strictly limited to winning.

Re: Myths in cycling: wider tires are slower

#372

Post by jacquesm »

nikau wrote: post #358
jacquesm wrote: post #325

Earlier quoted context omitted.

On tandems the problem hasn't been stopping power for years (every since we had hydraulic brakes this has been a solved problem). The bigger issue on a tandem is that when you're going downhill you will end up overheating your brake, whatever kind of system you are using. There is just too much kinetic energy to get rid of as heat for your normal brake system to be able to deal with.

With proper technique disc brakes wont overheat, especially now heatsinked pads and 203mm rotors are available. People who overheat brakes typically lack confidence and drag them constantly on descents causing overheating.

I take it you've never been on a tandem going downhill for a long stretch?

That's not a matter of confidence, that's purely a matter of safety.

Re: Myths in cycling: wider tires are slower

#374

Post by petre »

discreteevent wrote: post #315
sliken wrote: post #284

Earlier quoted context omitted.

Heh, rene makes a business out of being different, and has some good ideas, but they do push it to far sometimes. Sure I get it, a stoppie shows that the brakes are not a bottleneck, it's the traction. So sure, sometimes, on some bikes, with some riders, under some conditions you get perfect braking. However in the real world there's various rim surfaces (aluminum, steel, carbon fiber), with a variation of water, gri…

Agreed on everything except the road racers. Maybe some want discs but the pros don't. Discs are more likely to rub for them because pro cyclists generate enough power to twist the wheel. If you are trying to gain seconds over a few hours then the sound of rubbing must be torture. Chris Froome spoke out about it recently. Team Ineos just won the Giro and they don't use rim brakes because their sponsor does not oblige…

The industry can sell MTBs and gravel bikes where disc brakes have benefits. And now e-bikes, that's a huge market.

Re: Myths in cycling: wider tires are slower

#375

Post by jacquesm »

Xylakant wrote: post #342
jacquesm wrote: post #325

Earlier quoted context omitted.

On tandems the problem hasn't been stopping power for years (every since we had hydraulic brakes this has been a solved problem). The bigger issue on a tandem is that when you're going downhill you will end up overheating your brake, whatever kind of system you are using. There is just too much kinetic energy to get rid of as heat for your normal brake system to be able to deal with.

The kinetic energy depends on weight and speed. Cargo bikes easily come into that range, especially the fast 45km/h electric ones. Energy dissipation depends on the size of the rotor and sizes have been increasing substantially. When I bought mine, the standard disk size was 160mm, I opted for the upgrade to 180mm. The current generation of Riese-Müller Load uses dedicated cargo bike brakes with thicker rotors (2.3mm…

Yes, that Rohloff stuff is nice, and indeed a tiny bit expensive.

Re: Myths in cycling: wider tires are slower

#376

Post by plorkyeran »

rorykoehler wrote: post #250
plorkyeran wrote: post #36

Earlier quoted context omitted.

Yeah, when I first got my gravel bike I thought I'd be sacrificing some road performance for better flexibility and comfort, but that didn't happen. The actual result was that my times on smooth segments were unchanged and I've beaten many of my personal bests on rougher roads (and obviously it's much better on dirt). It's not a perfectly fair comparison because I did upgrade to a nicer bike in the process, but my pr…

Don't gravel bikes have much smaller gear ratios? There is no way a strong road cyclist would have the same times on a gravel bike as a road bike purely due to the size of the front chain ring. I run a semi-compact up front on my road bike and I can't go faster than 53kmh on the flat without my cadence getting too high to sustain for longer periods of time.

I run out of gears on flat terrain but that is a negligible portion of what I ride. I'd definitely expect a gravel bike to be a bigger handicap if you're riding mostly flat terrain and actually care about your speed on those sections.

Re: Myths in cycling: wider tires are slower

#377

Post by nikau »

jacquesm wrote: post #372
nikau wrote: post #358

Earlier quoted context omitted.

With proper technique disc brakes wont overheat, especially now heatsinked pads and 203mm rotors are available. People who overheat brakes typically lack confidence and drag them constantly on descents causing overheating.

I take it you've never been on a tandem going downhill for a long stretch? That's not a matter of confidence, that's purely a matter of safety.

I've been on a touring bike with a total weight of 130kg down massive hills in Japan

Re: Myths in cycling: wider tires are slower

#378

Post by jbluepolarbear »

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 use to live in Boulder CO and I would see a lot of people riding the fat tire bikes because they go over poor roads easy. Even see a bunch of people use them in the winter.

Re: Myths in cycling: wider tires are slower

#379

Post by timwaagh »

Case on aerodynamics is weak. I realize their analysis might make sense for extreme endurance events, but they don't generalize to road cycling. They did not test at common race speeds for cyclists. It's 5 watt at 30km/h. That might mean 14 or so watts at 50km/h. It doesn't seem like much but that's significant enough in a road race. And then there are sprints that take place at 60-70km/h

Re: Myths in cycling: wider tires are slower

#380

Post by petre »

jaypeg25 wrote: post #86
haswell wrote: post #52

Earlier quoted context omitted.

The Diverge was on my shortlist when I got the Topstone. At the time (2019), I think the Diverge defaulted to skinnier smoother tires. Can’t remember which tires specifically. The Topstone shipped with some pretty knobby WTBs that definitely had an impact on rolling resistance. If your tires are knobby/optimized for off-road, putting a slicker tire (the GK slicks are quite popular for good reason), I suspect you’ll n…

They came with 35mm "roadsport flak jacket" https://www.specialized.com/us/en/roadsport/p/155765?color=2... . They're pretty smooth overall, perhaps why I never really had an issue commuting with them, but I'm always looking to go faster!

You could try Gravelking slicks which are fast and still grippy or Conti GP5000s which are very fast.
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