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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

#171

Post by LAC-Tech »

kazinator wrote: post #39

Narrower tires, necessarily inflated to a high pressure, are actually inefficient on a bumpy surface. A tire's job is to absorb surface defects in the road, and that is not only for comfort, but rolling efficiency. The extreme example of this occurs off-road. Off-road vehicles benefit from wider tires that are inflated to a lower pressure. If you have an off-road vehicle, it behooves you to take some of the air out o…

> 25mm road bike tires basically require a polished velodrome; real roads consist of pitted, eroded and cracked asphalt.

Most roads in NZ are not even tarmac, they're chipseal. And people were still buying 23mm tires to ride them back in the day.

I felt like a trailblazer back in 2005 or so for getting 25mm :) I was hoping it wouldn't slow me down...

Re: Myths in cycling: wider tires are slower

#172

Post by matthewowen »

soperj wrote: post #92
matthewowen wrote: post #18

Earlier quoted context omitted.

I mean, they do, in the sense that they give a stronger and more secure connection to the pedals which lets riders commit more power. This is relative to casual toe clips or flats. Compared to old school clips + tightly fastened straps with dedicated shoes they aren’t a huge difference performance wise but no one rides those any more because they’re much more dangerous and much less convenient.

Once you're used to flats, this isn't an issue. If you have good pedals and good shoes, your feet don't normally move at all.

I mean, I ride flats on my mtb because the trade off makes sense, but I absolutely wouldn’t do a hard sprint out of the saddle in them like I would on clipless on my road bike.

Re: Myths in cycling: wider tires are slower

#173

Post by louthy »

soperj wrote: post #87
louthy wrote: post #60

Earlier quoted context omitted.

I’ve done many 100 mile+ sportives and have done both pushing down and pulling up.

You've done it just pulling up?

Both, pushing-and-pulling for rapid acceleration; as well as just pulling, often going up a hill to give the pushing muscles a rest.

Pushing and pulling at the same time takes a bit of time to get used to, but it can become quite natural after a while.

Re: Myths in cycling: wider tires are slower

#174

Post by uoaei »

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?

Path Less Pedalled recently had a great discussion on this with Josh Poertner, the owner and president of Silca, the tire pump company:

https://www.pathlesspedaled.com/2020/01/09/your-tires-are-ly...

Re: Myths in cycling: wider tires are slower

#175

Post by auxym »

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…

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 serious road racing.

Then for 20 years you couldn't really get a road bike with tires larger than 23 mm, which is totally illogical in places with less than perfect roads such as here in Canada.

Really happy that gravel bikes have brought back some sensibility to the sport, and that they provide a nice "all around" option in a market where manufacturers had been using "super specialization" of products to entice customers to buy more products.

Now I'm waiting for a similar trend to take over XC skiing!

Re: Myths in cycling: wider tires are slower

#176

Post by [deleted] »

carl_dr wrote: post #106
kazinator wrote: post #70

Earlier quoted context omitted.

I suspect that 42mm is already into diminishing returns for road cycling.

I am definitely slower - 4.5mph or so - on my 42mm gravel bike on road than I am on my 32mm road bike. But my road bike has slick tyres and the gravel bike’s tyres are more knobbly, and I run the gravel bike’s tyres at much lower pressure. (And there is the difference in geometry of each bike, too.) I’m not even sure you can buy 42mm slick tyres, so a like-for-like comparison is probably very hard.

[deleted]

Re: Myths in cycling: wider tires are slower

#177

Post by PaulDavisThe1st »

matsemann wrote: post #121
carl_dr wrote: post #7

I’ve ridden 25mm to 32mm tyres on the same bike, in the same season, and my (absolutely amateur, I’m 250lb and did 125 miles at 16mph) experience is that 32mm tyres are no slower, but are significantly more comfortable, and allow me to ride significantly longer with less fatigue. Does anyone else have any other data points?

Lots of the wattage gains in tests are often only noticeable when the speed approaches 40km/h. Wonder about the effect at pro levels, if 32mm is viable there. My longest is 300km with 35km/h avg (185 miles, ~22mph) running 25mm. No problems with comfort. Never tested other wheels on this bike. But I do have a gravel in same price range with wider tires. That I can follow easily in a group, but alone my speed is slowe…

This is a misconception, I think, although your experience seems like enough that I'm surprised you'd make it.

The "big" changes that happen as you approach and go beyond 40km/h are due to (aerodynamic) drag coefficient, which has very, very little to do with the width of your tires.

The changes that Heine is talking about are not related to drag coefficient at all.

Worth noting that Heine himself is a legendary ultra-cyclist. He holds the record on the Cannonball (Seattle to Spokane on I-90, 300 miles) in the self-supported category. He would routinely other riders (e.g. me) even though he had to pull off the interstate to restock on fluids and food.

Re: Myths in cycling: wider tires are slower

#178

Post by [deleted] »

auxym wrote: post #175
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…

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…

[deleted]

Re: Myths in cycling: wider tires are slower

#179

Post by PaulDavisThe1st »

carl_dr wrote: post #33
at-fates-hands wrote: post #24

Earlier quoted context omitted.

I was a life long flat pedal rider. Started working at a bike shop during college and one of the first things roadies told me was they are indeed much more efficient because you can push AND pull on your pedals - generating a lot more power and making the ability to sustain that power a lot easier.

I think this is a myth - you don’t pull on your pedals to make you more efficient, I think it’s the fact you are not continuously having to adjust your feet as you would on flat pedals. See https://www.bikeradar.com/advice/fitness-and-training/stop-p... for instance.

One issue I have with that bikeradar article is this quote:

>Undertake your next few leg-speed intervals at the same cadence (such as 105rpm), but aim to remain more firmly planted in the saddle, with your pelvis acting as a foundation for your legs. This will allow you to maintain chain tension through the entire stroke, eliminating the ‘thud’ through the top and bottom of the stroke (the ‘dead zones’) as your chain loses contact with the freehub

Anyone who experiences what the author describes as "the thud" is pedalling so badly that almost anything they do to improve their stroke is going to be huge win. I'm not sure his advice is on point for people who already have reasonable pedalling technique.

Re: Myths in cycling: wider tires are slower

#180

Post by PaulDavisThe1st »

soperj wrote: post #133
fsckboy wrote: post #109

Earlier quoted context omitted.

you should actively pull up your leg so the down leg is not working extra to lift it, and the pull up muscles are different muscles so your idle down muscles are still getting a rest. The pulling up of your leg results in easier pedaling overall, and it is relatively as if you are pulling up on the pedal. Should you actually then pull up? You should go for the most natural sustainable pedal motion for you. When I ped…

Honestly, go try biking by only pulling up. You don't pull up.

Just do one-legged drills for a bit. You definitely pull up when doing this. Transfer the same muscle activation to two legged cycling, and you're pulling up then too.
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