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Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

bicyclerollingresistance.com

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Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#91

Post by _Wintermute »

wiredfool wrote: post #80
_Wintermute wrote: post #44

Earlier quoted context omitted.

Not really, spokes work under tension rather than compression, you're essentially hanging from the top-most spokes on the wheel. Also if your spokes are too slack, they can move in the hub, cause wear, and are likely to snap at the elbow.

No. Wheels are a prestressed linear superposition of overall tension and a compressive load at the bottom. Generally, you'll see ~4 spokes at the bottom of the wheel relaxing to take the vertical load. (in a properly built wheel) This is due to rims not being completely rigid, but being a somewhat flexible beam. Rims are nowhere near rigid enough to do the "hang from the top" thing. Spokes will break at the elbow, bu…

The compressive load is negligible, that's why you can build a wheel entirely out of non-rigid spokes such as liteweight wheels or https://berdspokes.com/

Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#92

Post by zython »

prmoustache wrote: post #21
zython wrote: post #6

I wish there was a site that ranks tire grip. Only way to know right now is to see who is rolling faster through the corners than you and word of mouth.

Even that is not realistic as in contradiction with 4 wheels setup most people on pavement don't nearly reach the limit of grip on 2 wheels. The reward/risk ratio is not high enough. You'd need a bot for that on a skidpad test. Also on 2 wheels going fast around corners doesn't only involve grip but confidence. This is partly personal/psychological and partly based on feedback from the tire that comes on how the carc…

I race criteriums (and end up on the podium every once in a while) so I know relatively well how to corner. Fact is that there is no way to compare grip of tires except to trust a reputable manufacturer.

Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#93

Post by stephenbez »

ciupicri wrote: post #90
cogman10 wrote: post #76

Earlier quoted context omitted.

To add to this, unless you are actually competitively cycling (you probably aren't) this sort of thing makes pretty much no difference for someone that is using cycling for transport. It's a bit like obsessing over the lightest frame possible. Yeah, we can get a 1lb frame made of space materials but at the end of the day it's basically something that will reduce a cyclist's average speed by like 0.1mph. For anyone do…

I've switched to Schwalbe Marathon Almotion from some knobby Kenda and they made a night and day difference. It was a pleasure to ride in the city.

What type of difference did you notice? I switched from a stock Bontrager tires to Continental Grand Prix which are supposed to be high end and didn’t really notice too much of a difference.

Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#94

Post by garphunkle »

cogman10 wrote: post #76
303uru wrote: post #66

Earlier quoted context omitted.

As a cyclist, this is a situation in which I find this type of reviewing close to worthless to be honest. Throwing a tire on a metal roller is very far removed from riding unless you're on a velodrome or perfectly maintained road. This has led to a lot of push-back in the cycling community against this site and its findings. Their testing methodology, especially before they made recent changes, largely will prefer sk…

To add to this, unless you are actually competitively cycling (you probably aren't) this sort of thing makes pretty much no difference for someone that is using cycling for transport. It's a bit like obsessing over the lightest frame possible. Yeah, we can get a 1lb frame made of space materials but at the end of the day it's basically something that will reduce a cyclist's average speed by like 0.1mph. For anyone do…

I'm not sure if steel frames make a significant difference in comfort. If we measure comfort as deflection or vibration, then tire choice will have orders of magnitude more importance. When you have two springs in series, the combined spring constant is dominated by the weaker spring.

I race on a carbon frame with 30mm tires, and commute on a steel frame with 38mm tires for what it's worth.

Bike weight is irrelevant on flat roads. We should be obsessing over Watts/gram of drag, not Watts/kg if you're not a climber

Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#95

Post by garphunkle »

stephenbez wrote: post #93
ciupicri wrote: post #90

Earlier quoted context omitted.

I've switched to Schwalbe Marathon Almotion from some knobby Kenda and they made a night and day difference. It was a pleasure to ride in the city.

What type of difference did you notice? I switched from a stock Bontrager tires to Continental Grand Prix which are supposed to be high end and didn’t really notice too much of a difference.

Try using the Silca Tire Pressure calculator set to "Gravel Roads". This will give a safe PSI recommendation with a nod to comfort. I would ride 28mm GP4000s around 75 psi on a training ride with lots of chip seal

Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#96

Post by garphunkle »

ActorNightly wrote: post #72
edmundo wrote: post #57

Earlier quoted context omitted.

>Speeds over 30 mph on some descents All that aero is probably not working so well for you. Even on my mountain bike with grippy and wide tires I get over 40 mph. On my gravel I can hit over 50 mph, and thats with 45mm tires.

Its totally possible to hit over 40 mph on steep hills on an MTB, especially if you weigh more. I was more referring to slight grades with just pure rolling without pedaling. Im in Austin so I frequent COTA Bike nights on Tuesdays on the track. Coming down the hill from turn 1 with other riders is a very good test of aero efficiency, because there is a slight uphill after the bend. Couple of my friends ride gravel bi…

Shout-out to Violet Crown, PHENOM, Breakfast Club, UNITED, Night Owls, and all the other great cycling clubs in Austin! Wonderful community that I still miss.

Have you tried swapping bikes with your buddy? Are you two the same height/weight? Who has the more flexible spine? It would be fascinating to measure aerodynamic efficiency for two riders on the same bike. Is the more variation within populations, or between populations?

Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#97

Post by pandaman »

bennyelv wrote: post #53
pmontra wrote: post #52

Earlier quoted context omitted.

28 mm tires used to be huge tires. Pros didn't ride anything wider than 23 mm in the 90s. 25 mm would be for special occasions. 21 mm on tracks, sometimes even 19 mm. I think than Valverde used a 28 mm in a Roubaix and at the end of the race said that it was too much and not worth of the extra weight and front section. Every pro is riding on 30 or 32 mm now. Of course the rims are totally different and wrap those tir…

Unfortunately you cannot discount the “sponsor effect” here. Wheel manufacturers have been pushing wider rims because it helps them sell another set of wheels to everyone. In the days of rim brakes a wheel had a finite life (the length of time it took to wear down the braking surface). Then shimano and the frame builders pushed everyone to disc brakes, so the wheels now last for ever. What do you know, 2 years later…

I think you might be transposing the cause and effect. Mechanical rim brakes had been limiting the wheel width because of physics of leverage, disc brakes opened demand for wheels of any width and users naturally migrated to the wider wheels.

Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#98

Post by ip26 »

wink wrote: post #37
bradfa wrote: post #28

Earlier quoted context omitted.

It depends on what kinds of roads you ride on. If you're always riding nice smooth asphalt, then yes, high pressure narrow tires are going to be faster pretty much always. But if you're riding on really crappy asphalt, chipseal, or on dirt or gravel roads, then a wider more supple tire may be just as fast but a whole lot more comfortable due to the ability to run lower pressures. The power losses on a perfectly smoot…

The real eye-opener for me were that my kinda knobby MTB tires apparently have nearly the exact rolling resistance as my Schwalbe Marathon Plus on the Gravel Bike. So although they're a lot thinner, nothing is gained here at all. (If you assume enough pressure in the MTB tires on asphalt).

I regularly clock 21+ on my knobby, slack MTB on flat pavement, but struggle to break 20 on many other bikes…

Re: Bicycle Rolling Resistance: Tire Rolling Resistance Tests and More

#99

Post by pandaman »

bluecalm wrote: post #36
ActorNightly wrote: post #25

Earlier quoted context omitted.

>Unless you're on the ProTour You don't have to be on the Pro Tour to benefit from aero gains with narrower tires. Even moderately fit people usually can sustain 15 mph on flat, at which point aero gains start to matter. Even more for hilly terrain where you can easily pick up over 20 mph on descents. The wider tires roll more efficient at lower psi (when you have to air down for comfort). But roughness of pavement r…

Gravel bikes are going to transform in coming years as now they are neither very comfortable nor fast. It turns out that wider MTB tires are both faster (when it comes to rolling resistance) and way more comfortable and safer than gravel tires even on tarmac, let alone any kind of terrain. The reason is that soft casing is way more important than knobs when it comes to rolling resistance and MTB tires can be made sof…

Gravel bikes are much more comfortable and fast than road bikes on unpaved roads, which is what they are designed for. Wider wheels will add more weight and more angular momentum, making it harder to climb and harder to steer so you might need to replace the drop bar with the MTB flat bar and without the drops you can move the saddle into a more comfortable position as well... ending with a hardtail w/o the suspension fork.
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