Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Myths in cycling: wider tires are slower

renehersecycles.com

Post reply on HN
Print view View original

311–320 of 419 posts

Re: Myths in cycling: wider tires are slower

#311

Post by twic »

alanbernstein wrote: post #227
jmilloy wrote: post #219

I think folks might be interested to consider some of the other myths and tests in the series, such as: * Titanium is ligther than steel * Fenders slow you down * Stiffer frames are faster * Disc brakes work better than rim brakes * Higher tire pressure is faster * Bigger wheels roll faster https://www.renehersecycles.com/category/myths-in-cycling/ For more nuanced tire testing and results, check out these two more r…

These are interesting articles, but in https://www.renehersecycles.com/myth-12-disc-brakes-work-bet... , it just says outright "Many rim brakes for wide tires are too weak to do this quickly, so in the rain, you end up with almost no braking power at all." It's not a myth, it's just conditionally true.

This article doesn't have measurements, or references to measurements. It's just someone's opinions. Cycling already has plenty of those, thanks.

Re: Myths in cycling: wider tires are slower

#312

Post by nchi3 »

rorykoehler wrote: post #248
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 geometry of gravel bikes is much closer to 90s cross country mountain bikes than modern road bikes.

That's not really true. Gravel bikes have geometries ranging from aero race bike geometriea to hardtail MTBs. I'd say most have very similar geometries to endurance road bikes though (similar stack/reach, 71ish HT angle, 425-430mm chainstays)

Re: Myths in cycling: wider tires are slower

#313

Post by endless1234 »

soperj wrote: post #243
fsckboy wrote: post #211

Earlier quoted context omitted.

Honestly, I pull up. I'm not pulling the pedal up, I'm lifting the leg and pulling my foot up, getting it into postion to push again, same as I would do for running. you should try it, you can feel the relief in the pushing leg.

I'll go try it. Why couldn't you do that in flats?

You do it with flats too. Clipped in feet just makes it so you don't need to worry about where the foot ends up after that. But it's not a huge difference.

Re: Myths in cycling: wider tires are slower

#314

Post by suprfnk »

dncornholio wrote: post #308

It's not about drag or friction, it's about weight. Wider tires are heavier. Which is a big no no in professional cycling where every milligram counts.

The article mentions this, and concludes that the weight doesn't matter as much as people seem to believe:

> Wider tires are a little heavier than narrow ones. The difference is smaller than many cyclists imagine – the air inside a wide tire doesn’t add weight – but a wide tire has a little more rubber and casing. Won’t this make the wider tires harder to accelerate? The answer is “No.”

> The reason is simple: Bicycles don’t accelerate very quickly. Even a professional bike racer’s power-to-weight ratio is far less than that of the slowest economy cars, and those don’t exactly push you back in the seat when you floor the throttle. Bikes don’t accelerate fast enough for small changes in wheel weight to make a difference.

> That is why professional sprinters can use relatively large wheels (which inherently are heavier) and still win races. 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.)

Re: Myths in cycling: wider tires are slower

#315

Post by discreteevent »

sliken wrote: post #284
jmilloy wrote: post #191

Earlier quoted context omitted.

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...

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 them to. It looks like the reason pro racers have discs is because the bike industry makes them. This is so that they can sell new bikes to people who already have a perfectly good one. It makes no sense for pro riders to have disc brakes. Their high end rim brakes are looked after by mechanics, they are lighter, they don't rub, wheel changes are easier and pros don't do a lot of braking anyway.

Re: Myths in cycling: wider tires are slower

#316

Post by nchie »

dahart wrote: post #51
louthy wrote: post #2

If that were the case, surely Tour de France riders would use wider tyres to gain more grip going around corners, especially in time-trials or stages with sprint finishes. Doesn’t a greater surface area touching the floor means more frictional effects when pushing against the road?

> Doesn’t a greater surface area touching the floor means more frictional effects when pushing against the road? Good question because at first I thought it might be negligible due to the tire normally being in a state of static friction relative to the road. But some quick searches showed me that rolling resistance is related to how large the contact point is, like you suggest, along with a variety of other factors.…

I love brr.com and have used them a lot, but in the context of this thread, it's important to consider that the surface they test the tires against do not have the kind of imperfections you see on the road. This means lower pressure will always perform worse in their tests, which goes against the more recent consensus in that each road has an optimal pressure depending on its roughness.

Re: Myths in cycling: wider tires are slower

#317

Post by theelous3 »

jmilloy wrote: post #219

I think folks might be interested to consider some of the other myths and tests in the series, such as: * Titanium is ligther than steel * Fenders slow you down * Stiffer frames are faster * Disc brakes work better than rim brakes * Higher tire pressure is faster * Bigger wheels roll faster https://www.renehersecycles.com/category/myths-in-cycling/ For more nuanced tire testing and results, check out these two more r…

> Disc brakes work better than rim brakes

They really do though. Hydraulic disk breaks have way more stopping power, higher resistance to wet and dirt, don't weaken with each use, and are both lower maintenance in the long and short term, and easier to service and get correct.

It's not out of ignorance the bike uses who need brakes the most 100% use disks (mountain biking).

The argument made is that "rim breaks are disk brakes". This is true in the same sense that topologically humans are donut shaped. It ignores all subtilty. Wheels flex in turns where your disks do not, etc etc forever.

Re: Myths in cycling: wider tires are slower

#318

Post by nchie »

loeg wrote: post #153
mantas wrote: post #38

Earlier quoted context omitted.

It's pretty big when you take into account whole context. Stuck up "socks size is a rule" UCI, historical norms, technical limitations (25mm is a limit for caliper brakes), tire tech (wider tires used to be heavy).... My prediction is 27mm being the norm in next 5 years. Currently I'm riding a decade-old road bike. It was fancy at the time because it fit 25mm tires without issues. People would give me shit for "slow"…

25mm is not a limit for caliper brakes? No idea why you claim that. One of my bikes has calipers and can fit 33mm tires. Also 28mm is extremely common; 27mm doesn't exist.

Nit-picking, but 27mm is very common as the "actual width" of tyres branded 25mm.

Re: Myths in cycling: wider tires are slower

#319

Post by namdnay »

gield wrote: post #272
wolrah wrote: post #244

Earlier quoted context omitted.

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.

The fatter tyres do cushion it a bit. And most "cycle to work" bikes I've seen (especially ebikes) will have a small front shock

Re: Myths in cycling: wider tires are slower

#320

Post by egman_ekki »

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.

interesting, maybe different frame geometry contributed as well?
Post reply on HN