Tyres for time trialling

onabike

hi

looking for suggestions for tyres for use in ten mile time trials.

At the moment I have standard michelin pros and tubes, just grabbed off the shelf from my local bike shop. One guy at the TT told me these tyes are "heavy" and advised me to try some others, but I cant remember which ones he suggested now.
I usually get about 26.10, and this is my first season. So thats my level.

Alex_Simmons/RST

onabike wrote:

hi

looking for suggestions for tyres for use in ten mile time trials.

At the moment I have standard michelin pros and tubes, just grabbed off the shelf from my local bike shop. One guy at the TT told me these tyes are "heavy" and advised me to try some others, but I cant remember which ones he suggested now.
I usually get about 26.10, and this is my first season. So thats my level.

Which Michelin Pros? There are several models with Michelin and Pro in the name. Some are pretty fast tyres (e.g. Michelin Pro 2 Light SC 23), others are slow.

With tyres, weight in itself is only a minor issue. The things that matter for TTs are:
- rolling reisistance
- aerodynamics (usually thinner is better but it depends a little on the rim choice)
- puncture resistance (depends on quality of road surface and conditions)
- durability (may be a consideration)
- cost (may be a consideration)

Fast is not usually cheap. Fast also tends not to equate with durability either.

Also, use latex tubes for improved rolling resistance but you need to learn how to install such a tube properly as they are easily damaged which can show up as a pinch flat at the most inopportune time.

For racing 10s and assuming reasonably decent roads, then have a look at the tyres at the top of the list:

http://biketechreview.com/tires/images/ ... g_rev7.pdf

(it is possible you may need to be a forum member to view the file).

But if you need to be concerned with puncture resistance, cost and durability, then you might need to look further down the list.

bahzob

Another good tyre review (including tests for puncture resistance and wet weather grip is here):
http://www.conti-tyres.co.uk/conticycle/road_tyres/attack%20force/Resistance%20Fighters.pdf

I use the GP4000s that came top and have found them to be very good

bill57

http://biketechreview.com/tires/images/ ... g_rev7.pdf

This has to rank amongst the most meaningless data ever presented?

Alex_Simmons/RST

bill57 wrote:

http://biketechreview.com/tires/images/AFM_tire_testing_rev7.pdf

This has to rank amongst the most meaningless data ever presented?

While I take some of the data with a grain of salt, in what way do you mean?

Providing a Crr number for tyres tested under the same conditions is useful info.

bill57

I was going to write a lengthy reply to this, on how you can't present data like this without any explanation of how it was arrived at, and expect readers to just accept your results at face value. For example there's nothing to even tell the casual reader what crr actually means. I was also going to say "Who's Tom Anhalt?", so I googled him and found the complete article,

http://teamnaturespath.com/Files/Tires/Tire_Data.pdf

I had no beef with the data itself, it was the exclusion of any supporting experimental notes that prompted my comment. Just can't shake the scientist out of me, I'm afraid.

Alex_Simmons/RST

bill57 wrote:

I was going to write a lengthy reply to this, on how you can't present data like this without any explanation of how it was arrived at, and expect readers to just accept your results at face value. For example there's nothing to even tell the casual reader what crr actually means. I was also going to say "Who's Tom Anhalt?", so I googled him and found the complete article,

http://teamnaturespath.com/Files/Tires/Tire_Data.pdf

I had no beef with the data itself, it was the exclusion of any supporting experimental notes that prompted my comment. Just can't shake the scientist out of me, I'm afraid.

I take your point but since the forum on which it was posted was included in the link, why not go there and ask or search the forum a little further.

For those that are wondering, Crr stands for Coefficient of Rolling Resistance. It is a unitless measure of the resistance of a tyre rolling on a given surface. Combined with mass and speed, one can determine how much power is required to overcome such resistance (or how much difference in speed is possible with the same power with a different Crr).

A lower Crr indicates a faster tyre.

For example, I have calculated that in the Stage 4 ITT at this year's TdF, David Millar's tyres had a Crr of ~ 0.0033, which is pretty low for on the road (indicates both fast tyres and a smooth road). If he was using a normal road tyre with a Crr of 0.005, then his time in that TT would have been in the order of 38 seconds (1.3 sec/km) slower.

That sort of time difference I suggest would be of interest to TT riders.

Despite what Tom Compton has on his Analyticcycling.com site, the following would be a guide to rolling resistance based on my own experience in measuring these things from field tests:

Indoor wooden velodome is ~ 0.0025
Typical good road with normal road tyres ~ 0.0045 - 0.0055
Crummy roads ~ well anything goes!

Note, the best Dr Dave Martin found at the DGV in Sydney for the AIS was 0.0023 IIRC. I have been able to arrive at similar numbers for some of my athletes.

Crr can be reasonably estimated with the aid of field tests conducted using an on-bike power meter although it needs some special techniques to separate the Crr number from the Coefficient of Drag Area (CdA).