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Fastest tires for racing?

post #1 of 6
Thread Starter 

I have my first race coming up sep 10th and im looking to get the bike as fast as possible

 

whats the fastest tire out there, looking at a slick type tire

post #2 of 6

Check out this rolling resistance test.  The tyres with an 'X' next to them are tubulars. 

 

http://www.biketechreview.com/tires_old/images/AFM_tire_testing_rev9.pdf

 

You can get really fast tyres, but it depends how much durability and puncture resistance you want, and how much you wanna pay.  Generally speaking, the tyres are at the top on the list, to about the mark of 14watts of rolling resistance, are fast, but not very durable and usually not as puncture resistant as the 'slower' tyres. 

 

Also, note that latex tubes can reduce rr up to about 2.5w per tyre!!   

post #3 of 6

The list quoted by 531 is very useful from the stand point of being able to separate tyres into general groups (eg "fast", "medium" or "slow").  This is a big improvement on the past situation of no available information.

 

However, the equipment used in the test and the lack of documentation on the method lead me to be very wary of actually trusting the numbers quoted.  There are a number of factors which have either been ignored or not documented by the author so I do not place as much faith in these measurements as he does.  Therefore I wouldn't use the list to pick between tyres which are closer than 10% in their Crr measurements.

post #4 of 6

Ha! Yeah, who knows if the actual figures mean anything?!  But, from my experience of using many of the clinchers on there, the list is pretty much in the right order. 

post #5 of 6

I know what Crr is supposed to mean but I can't actually tell if the guy has really measured that or just a combination of the effective Crr due to the drive train, bearings, roller belt and tyres together.  I suspect it is the latter.  Even if that is what he has measured, the data could still be useful but I sincerely doubt his quoted uncertainty of 1.3%, especially since the SRM pro he used has a certified uncertainty of 2%.  Added to that is the effect of the type of wheel used in the test, the statistical issues associated with only measuring one tyre of each type (rather than an appropriate statistical sample batch) and the fact that the tacx rollers place higher than normal deflections in the tyres.

 

Cyclists (that is normal, non-technical cyclists - technical people have known this for a long long time) have begun to realise that real world Crr is the result of a interplay between the road surface and the tyre and that different surfaces actually place different demands on the tyre.  Below is a link to an article which shows that tyre Crr behaves significantly differently on the road compared to rollers. The author also introduces the two parameters which we really need to know: The minimum possible Crr and ideal pressure for real road surfaces:

 

http://www.slowtwitch.com/Tech/What_s_in_a_tube__1034.html

 

What the author calls the "breakpoint" (I would call it a minimum) is pretty clear. The position of this minimum (ie the minimum Crr and the pressure at which it occurs) will vary a bit with tyre, the load on the tyre (rider weight) and with the roughness of the road surface.

 

It is this minimum point for Crr and ideal pressure which we need to know, but unfortunately there is no study yet that has made complete measurements of it on the "average" road surface.  Thankfully a fairly simple measurement method does exist, occasionally called the Virtual Elevation technique.  With this it will only be a matter of time before someone starts coming up with real world results.

post #6 of 6

To the Original Poster.

 

I'm sorry. I have kind of hijacked your thread with the semantics of rolling resistance.

 

It suffices to say that, as long as you choose a tyre from the first page or two of the list posted by 531Aussie, you will have selected a tyre at the racy end of the spectrum.

 

Combine that with no more than 120psi in the rear and you will be close to as fast as possible.

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