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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

#271

Post by matsemann »

vecinu wrote: post #208
usrusr wrote: post #186

Earlier quoted context omitted.

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…

The only caveat is carbon wheels. I hate rim brakes on carbon wheels,they legitimately suck and disc is way better for that application. I actually just sold my carbon wheels and downgraded back to aluminium until I buy a disc bike for the long term.

Rim breaking on deep dish tempo wheels sounds horrifying.

Re: Myths in cycling: wider tires are slower

#272

Post by gield »

wolrah wrote: post #244
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…

The second most annoying thing to me about cyclists are the number of them who complain about the quality of the road or path while riding what is more or less a race bike. Shockingly, road race vehicles of any variety generally are not built for comfort or ability to handle less than ideal conditions. Stop acting like you think you're in the TdF and get a bike that makes sense for where you ride.

If the quality of the road is bad, gravel bikes are equally as uncomfortable as race bikes. Not talking about non-asphalted roads as race bikes are of course not made for those.

Re: Myths in cycling: wider tires are slower

#273

Post by pharmakom »

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 cannot fit around a wide tyre. Mechanical disc brakes with good pads (this is key, swap them out if necessary) are much more powerful than road rim brakes.

Re: Myths in cycling: wider tires are slower

#274

Post by vladvasiliu »

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'm very happy with this trend, too.

I've always had full-on road-bikes (skinny tyres, etc). While those are great for a ride out on the hills around my parents' house, I now live in the city where the roads are in a pretty bad shape, and more importantly they're very often paved with cobblestones (probably the very same ones laid down by the Romans).

I'm looking to buy an electric bike for my commute, and most bikes have the "upright" geometry. Maybe it's because of my habits, but I don't feel as safe on those, I find them less manoeuvrable and less efficient if I need to pedal hard (though with the electric motor that last point might be less important).

I'm happy those new "all-track" as they're called here exist, with disk brakes and all the creature comforts of regular "city bikes" but with a more familiar-to-me riding position. I'm less happy with those bikes always having a suspended fork, which I've always seen as useless for road bikes, but oh well...

Re: Myths in cycling: wider tires are slower

#275

Post by pharmakom »

plorkyeran wrote: post #53
jaypeg25 wrote: post #48

Earlier quoted context omitted.

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.

The Pathfinder tires that come stock on recent Diverges are pretty widely regarded as not just the worst part of the bike, but a sort of bafflingly bad choice because they aren't even cheap. If you're looking to spend some money upgrading your bike, they're a good place to start.

Really? Loads of Unbound Gravel finishers were on Pathfinders.

Re: Myths in cycling: wider tires are slower

#276

Post by sliken »

usrusr wrote: post #186
jiscariot wrote: post #137

Earlier quoted context omitted.

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…

I'd had just about every cable actuated brakes. Old school cantilevers, various flavors, u-brakes, v-brakes, cable-discs etc. etc. etc.

Didn't realize what I was missing till I tried a nice set of hydraulic discs, I'll never go back.

Re: Myths in cycling: wider tires are slower

#277

Post by pharmakom »

jmilloy wrote: post #194
pmontra wrote: post #151

Earlier quoted context omitted.

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.

Another big difference is simply the quality of the tire. A supple 48mm knobby could be faster than a stiff slick (and we know the width doesn't matter). The Rene Herse Oracle Ridge knobbies are 48mm, quite supple and corner well on the road, plus they are noise cancelling!

Width matters for air resistance. I can hear the air coming off my 2.1 inch tyres. Rene Herse knob bikes are still pretty loud in my experience!

Re: Myths in cycling: wider tires are slower

#278

Post by whakim »

kohlerm wrote: post #261
whakim wrote: post #239

Earlier quoted context omitted.

You're definitely faster with the GP5000s and it's not just an illusion. The GP5000 is an extremely fast tire - some of the lowest rolling resistance out there as measured scientifically [1]. Even the fastest 38mm tires are probably going to cost you minimum 10 watts per tire over the GP5000; perhaps even double that. [1] https://www.bicyclerollingresistance.com/road-bike-reviews/c...

They test AFAIK under ideal smooth road conditions asconfirmed by the picture. On bumpy roads the 10 watts advantage might quickly disappear

10 watts per tire is an absolutely enormous amount given that the rolling resistance of the tire itself is only 10 watts in total. The BRR test also claims that "the drum is covered with diamond plate to simulate an average road" - it isn't completely smooth [1]. If you're riding on roads that are so bumpy that you really need super low pressures (e.g. significantly lower than the 60psi you can run on a 28mm GP5000) then rolling resistance isn't a high priority. But honestly very few actual roads are that bad.

[1] https://www.bicyclerollingresistance.com/the-test

Re: Myths in cycling: wider tires are slower

#279

Post by vladvasiliu »

rorykoehler wrote: post #269
egman_ekki wrote: post #266

Earlier quoted context omitted.

I don't think the difference is that large, but there is some. I haven't tried myself, but would be interesting to test it against each other. You can compare gearing ratios on 99spokes, e.g. https://99spokes.com/compare?bikes=scott-speedster-gravel-20...

I've been road riding with people who switched to gravel bikes and they were suddenly noticeably slower. They also seemed to run out of gas earlier which means they were expending more energy to keep up.

Weren't those new bikes heavier?

My own road bike is nothing particularly fancy, but it's very light. Just because those bikes may be made to take more of a beating than a road-bike, they may be heavier. I'm thinking in particular tougher wheels and front work, possibly the whole frame.

Re: Myths in cycling: wider tires are slower

#280

Post by rukuu001 »

ehnto wrote: post #231
rukuu001 wrote: post #187

Earlier quoted context omitted.

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

Definitely still available. That segment of the industry has exploded. Another great manufacturer for touring/adventure bikes is Bombtrack. Many touring/adventure bikes will double as way better commuter than a road bike I feel. They are set up for comfort, long hours in the saddle, and usually have with luggage mounts.

I haven't had to pay attention to that market because my 2007 Surly is still going strong :)
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