Quote:
Originally Posted by CapriRacer
First, no one is going to be able to answer your question with any degree of accuracy. To understand why, you need to read this:
Barry's Tire Tech
and this:
Barry's Tire Tech |
Is it certain that the different tyres were indeed tested with a different load ?
If I was to study the effects of tyre size, I'd study the effect of all allowed tyre sizes on a given vehicle (i.e. always with the same vehicle weight).
In that light, I'd come to the opposite conclusion - and each and every car manufacturer is complying with that conclusion as they're fitting their eco-models with skinny tyres.
If wider tyres were beneficial, surely they'd all fit those instead of narrower tyres ?
The study also has a graph (p. 35) correlating RR (actual force, not coefficient) to LI, with higher LI also resulting in higher RR.
(83% correlation, and even 86% to max. sidewall load)
Higher LI (and max sidewall load) usually goes together with wider, lower profile tyres.
Same with tyre weight, overall diameter - which both show a 75% correlation with RR - where increasing weight and diameter would usually indicate a wider, lower profile tyre.
All these then result in the graph on page 30, clearly indicating higher RR (actual force) for the wider tyres.
(What I'm missing in the study, is a graph of RR versus profile height.)
In the end, you need to overcome the actual RR force of a tyre at a given load, not a RR coefficient.
The study concludes :
Rolling resistance rolling forces and rolling resistance coefficients did not correlate.
But I fail to see where it comes to the conclussion that wider is better.