Quoted message said:I thougt that makers of bicycle tires would have experimentally or
scientifically based knowledge as a foundation of their production.
Therefore I directed my question about rolling resistance to Continental
Tires
- and the production manager kindly sent me a reply that is surprisning as
well as interesing.
If you have access to a decent public library, you should be able to
locate many articles on testing rolling resistance. One in particular
deals with using coast-down tests to determine tire rolling resistance.
The article is "Tire Rolling Resistance Measurements From Coast-Down
Tests", SAE #760153. Yes, it is automotive related, but the procedure
should work fine. If you check SAE.org, there are many other papers on
this topic listed, such as "Determination of Vehicle Drag Contributions
Quoted message said:From Coast-Down Tests", SAE #720099.
You'll probably find that air drag dominates tire rolling resistance at
higher speeds. But using coastdown tests, you should be able to figure
out if a 25mm tire has higher or lower rolling resistance than a 23mm
tire, assuming same rider, same bike, same environment (terrain, wind,
temp, etc.), recommended inflation pressures, and same type of tire.
My butt-gauge indicates that 25mm tires (Veloflex Roubaix - tubular)
grip better, and are more compliant than 23mm tires of the same
manufacturer. So, I believe I'm faster in turns, descents. I certainly
push harder. The tires are more compliant on rough surfaces, so it's
easier to go harder as the ride is smoother. They roll about the same.
The 25mm tire is somewhat harder to sprint or climb with since it is
heavier, and the diameter is slightly larger.
Regards,
Rob