Tire Rolling Resistance Study

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HermesSport
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by HermesSport

Has anyone attempted that CRR+Aero test with identical models of tires on the same rims, just with different tire widths?
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stoney
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by stoney

HermesSport wrote:Has anyone attempted that CRR+Aero test with identical models of tires on the same rims, just with different tire widths?


That's what I'd love to see. For instance, if my clinchers are 23mm wide, would I be faster on the road riding GP4000s II 23's or 25's when considering both CRR and Aero data? I'm assuming the 23's would make a better aero profile with my 23 rims.

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mrlobber
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by mrlobber

... might be different results with different wheels because each manufacturer says that its rims are optimized for different tyre profiles.

For instance, "older" Enve Smart wheels were said to be best for 23mm tyres, newer versions they say are better with 25mm and so on.
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by helldiver

Here you go: http://bikeblather.blogspot.sk/2015/10/win-tunnel-playtime-part-1.html
The Guy tested different rim-tyre combinations, including 22mm and 24mm tyres on the same rims (even quite wide rims, as HED Jet6+) and obviously narrower was better for aero each time.
He also tested CRR (different article).

Philbar72
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by Philbar72

F45 wrote:I think we can agree that Specialized has the best tread compound.


Used some of their s-works 24mm clinchers. I have to disagree. They corner poorly, mechanical grip seems to be average, cut easily and simply put I can’t recommend them. This is in comparison to gp4000s II and Schwalbe one Tyres. The Schwalbe for me hit the sweet spot of feedback, grip and cut resistance.

note this is for clinchers.

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by mattr

Tinea Pedis wrote:
mattr wrote:I wish people would stop calling that a "test".

What is it then?
At best its a simple comparison.

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by kgt

And clever marketing (for the website itself).

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by Johnnysmooth

Philbar72 wrote:
F45 wrote:I think we can agree that Specialized has the best tread compound.


Used some of their s-works 24mm clinchers. I have to disagree. They corner poorly, mechanical grip seems to be average, cut easily and simply put I can’t recommend them. This is in comparison to gp4000s II and Schwalbe one Tyres. The Schwalbe for me hit the sweet spot of feedback, grip and cut resistance.

note this is for clinchers.


And this gets to the crux of the biscuit...
Tire choice is a combination of factors. Rolling resistance, while important, is not the overriding factor for me.
I've had issues with conti clinchers - sidewall failures - though I do like the conti comp tubies, good durability and cornering.
Been quite happy with Schwalbe clinchers - nice balance of feel, cornering and durability.
Veloflex clinchers have been a fav for years - wonderful road feel
Been happy with Vitt Corsas for same reason as veloflex
And just bought a new set of my fav winter tires - Vittoria's Pave 27mm, in green of course.

Horses for courses...
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by KWalker

Does anyone have a link to the raw dataset? I'd like to do a re-analysis in my spare time since I find the presentation and formatting of the results a bit poor.

And technically, it is not a test.
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by Tinea Pedis

mattr wrote:
Tinea Pedis wrote:
mattr wrote:I wish people would stop calling that a "test".

What is it then?
At best its a simple comparison.

A rose by any other name...

Writer reviews a bike. It's not a 'bike comparison', it's a 'bike test'. I'll sleep fine if you don't think it's a test. But fact is a 'compartaive test' is still a test. And it's not thr most robust (he could have used Chung's Aerolab) but damn it's better than the majority of the Internet going off "I think...". Give them a little credit.

And if all you're seeing is the native adverting you're missing the forest for the trees.

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by mattr

...

KWalker
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by KWalker

Sorry, but that's wrong. A test requires a hypothesis, methods for measuring/proving the hypothesis, etc. It follows the scientific method so to speak.

Hoping on a bike and saying you like this or that isn't really a test. Having no base hypothesis means no test question. Just getting data and plotting it is a comparison since things are measured against each other, but with no prediction or explanation as to why results were achieved.
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Tinea Pedis
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by Tinea Pedis

test

A procedure for critical evaluation; a means of determining the presence, quality, or truth of something; a trial: a test of one's eyesight; subjecting a hypothesis to a test; a test of an athlete's endurance.


http://www.thefreedictionary.com/test

Or any other resource you'd like to use for a definition.

A hypothesis is tested but you don't need one to still have a test.


Still little lost again to why people want to tear down the credibility of this test. Not that it's a peer reviewed piece - but again it's still a great step in the right direction in trying to provide some real-world quantitative data for people to consider. End of the day ride what you please - as you can make a case for either choice. One just happens to be increasingly quantitatively based and the other more qualitative.

/done

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by KWalker

Using your link:
1. A procedure for critical evaluation; a means of determining the presence, quality, or truth of something; a trial: a test of one's eyesight; subjecting a hypothesis to a test; a test of an athlete's endurance.Well, it doesn't satisfy this because, as I said, there is no hypothesis or piece of knowledge being evaluated. It is exploratory and creating knowledge for future tests. For example, One could re-test the tires in X months to compare aging and crr of different tires. Or determine if a width is faster than another. In this case that is all done post hoc, not ad-hoc.
2. A series of questions, problems, or physical responses designed to determine knowledge, intelligence, or ability.There were some questions posted, I will give you that.
3. A basis for evaluation or judgment: "A test of democratic government is how Congress and the president work together" (Haynes Johnson).Much closer
4. Chemistry A physical or chemical change by which a substance may be detected or its properties ascertained.N/A

I think this is worth reading to define why those of us that conduct hypothesis tests or are analytic by trade tend to have an issue with the terms cycling publications use for their "tests": http://www.livescience.com/21569-deduct ... ction.html

I'm not saying its a bad test, but in terms of an analysis, it is not one. It does provide the basis for future analyses, which is great since there really isn't much in the way of open knowledge sharing in cycling.
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