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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

#351

Post by rorykoehler »

blakblakarak wrote: post #329
rorykoehler wrote: post #250

Earlier quoted context omitted.

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.

If you can spin out a 50x11 or similar on the flat you're in a very small minority of cyclists...

I'm not spinning out but I am spinning faster than I can sustain / is efficient. I'm looking for the next gear basically. Spinning out is much faster and requires and descent (for me at least). Based on Strava I'm not that strong. Top 40% maybe. If I was racing I'd be cat 4. My observation is more to do with stronger riders than I am. Once you get to a certain speed/ftp all the considerations like rolling resistance, gearing, aero etc become much more obvious. If you are averaging 29.5km/h like in the test you might think optimisations don't make much difference but if you average 40kmh+ you will know they do.

They even note this in the article "If you ride much faster, then it’s possible that wider tires have a little more wind resistance, but the difference will be so small that it’ll get lost in all the other factors that influence your bike’s speed. On the other hand, if you ride slower, then the advantage of wider tires will be even greater."

Re: Myths in cycling: wider tires are slower

#352

Post by loonster »

audiometry wrote: post #241
jmilloy wrote: post #213

Earlier quoted context omitted.

Yeah, these supple tires are faster but less delicate than you think. I do think replacing your stock tire with a supple tire at the same width will be a huge upgrade, and wider would just give you a little bit more.

The problem I’ve experienced with these expensive tires (compass, gran bois, etc) isn’t their durability against road debris. It’s that their “supple” sidewalls don’t hold up to the equatorial sun I suffer under. They degrade far faster than the tire rubber degrades. I like riding these tires but they are expensive fast consumables.

Maybe fenders would improve your tire life?

Re: Myths in cycling: wider tires are slower

#353

Post by rleigh »

mymythisisthis wrote: post #349
sliken wrote: post #295

Earlier quoted context omitted.

Heh, yes, less maintenance, but also less finicky. Brake pads on rim brakes are a nightmare. They follow a 3-d arc as they approach the rim, which is itself a very complicated 3d surface. Ideally the front edge of the brake pad hits slightly before the rear edge, to avoid squeal... but not too much or it will engage too softly. Even minor wear changes the engagement point. Cables need maintenance, they wear, get kink…

What about cable over fluid disc brakes for a commute bicycle?

Once you've used hydraulics, you never want to go back to cable. They are so much better on all counts that the tiny weight gain pales into insignificance.

Re: Myths in cycling: wider tires are slower

#354

Post by wiredfool »

londons_explore wrote: post #203
wiredfool wrote: post #129

Earlier quoted context omitted.

I’ve ridden their extra lights into some pretty ridiculous places, and commuted on them in a city, and they’re as trouble free as any other tire I’ve had. (In about 7k miles) I would recommend taking them on technical single track, but they rock for any sort of road riding. They’re certainly fine for the gravel I’ve seen. (And by trouble free, I mean no flats that I can blame on the tire or some damage to it. I’ve ha…

The real test for a city is how many hypodermic needles and smashed bottles can you ride over before being stranded by a puncture in a not-so-nice area of town at night...

My old narrow tires would tend to collect cuts in the tread, sidewall cuts, and other damage. After a thousand miles or so, I’d tend to be able to see the cords in some of the cuts, and I’d occasionally dig bits of glass or stone out of the rubber.

I just don’t see the same sort of damage after 3500 miles on a pair of 650x42 tires. I’m not generally riding over needles or goat heads, and I avoid broken glass as much as possible.

Re: Myths in cycling: wider tires are slower

#355

Post by wiredfool »

et-al wrote: post #158
wiredfool wrote: post #128

Earlier quoted context omitted.

They (Jan and the RH crew) have done several versions of this over the years, and the takeaway is that some gravel bikes feel slower due to geometry, rider position, Q factor, and so on, but the tire width isn’t a factor. (I think one was testing the open vs firefly, with similar riding positions but drastically different wheels)

Don't forget Jan's signature word: planing . This is prob the Open vs Firefly test you're thinking of: https://www.renehersecycles.com/what-makes-a-bike-fast/ In the test, they apparently isolated the wheel weight by swapping out wheels on the slower-on-paper Firefly and the bike didn't ride up the hill significantly faster. However Jan Heine's experiments are often pseudo-sciencey and subject to rider effort. In thi…

Jan has a PhD in a science (geo I think), and has done bike experiments with Jim Papadapolis. I would generally take his experiments over most random ones cited on the net.

Gospel truth? No. Probably not. Generally pretty good if you look at what he’s actually testing? I think so.

(Disclaimer, Jan was a teammate 25 years ago, and apart from not having talked since then, I’d consider him a friend)

Re: Myths in cycling: wider tires are slower

#356

Post by zikduruqe »

rukuu001 wrote: post #187
auxym wrote: post #175

Earlier quoted context omitted.

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

Fatties Fit Fine on most of their bikes.

I ride 40mm tires on my Long Haul Trucker.

Re: Myths in cycling: wider tires are slower

#357

Post by ambentzen »

jmilloy wrote: post #191
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.

Indeed! In the same series: Myth: disc brakes work better than rim brakes[0]. The rim is the rotor of a bit disc brake rotor that cools better and doesn't add any weight. But the wider tires make disc brakes a necessary choice. [0] https://www.renehersecycles.com/myth-12-disc-brakes-work-bet...

While in absolute terms rim brakes are probably just as good as disc brakes. The difference lies in the feeling and modulation of the forces.

Also, the disc is a consumable on both types. I have worn down rims to the point where I was scared to use the wheels.

The initial setup can be a bit annoying with hydro discs, but it's a tradeoff I'm happy with.

Re: Myths in cycling: wider tires are slower

#358

Post by nikau »

jacquesm wrote: post #325
Xylakant wrote: post #255

Earlier quoted context omitted.

You should also keep in mind that the articles are slightly dated, so technical improvements may have changed the equation. For example in the comments thread for the disc brake article, people mention that they cannot find disc rotors with sufficient size for tandems. With the rise of cargo and electric bikes, disc brakes with pretty massive stopping power have come to market. Mine can safely stop the bike, me, plus…

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.

Re: Myths in cycling: wider tires are slower

#359

Post by mariusor »

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…

> and pros don't do a lot of braking anyway.

That's just not true, there's plenty of braking in the mountain stages. I sincerely doubt that going 90-100Km/h into a hairpin is easier with rim brakes.

Ineos had two accidents this season on descents, first with Moscon in the Giro and then with Thomas in Criterium du Dauphine and even if they might have been just flukes, I'm sure the team is asking themselves questions.

Re: Myths in cycling: wider tires are slower

#360

Post by usrusr »

sliken wrote: post #276
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…

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.

That list is looking suspiciously void of brakes that would have trouble fitting a 28 mm tire. Yes, disc brakes can be very good, but the gap is much smaller than must people would expect.
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