Quote:
Originally Posted by Frank Lee
IMHO Capri Racer's advice to go wide makes sense if you are loading the tires to near max capacity. I would expect a tire engineer- who is always concerned with liability issues- to have that position.
However I think if your vehicle is always at the lightly loaded end of the spectrum, fe gains can be had from going narrower, to tires with fewer plies and thinner sidewalls and treads. I have yet to personally test that theory.
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Quote:
Originally Posted by RedDevil
The one does not have to rule out the other. Give me a tire thats both narrow and has thin layers anytime, if it is a quality tire and strong (enough).
Was wondering, are there commercially available tires where the layers have indeed been thinned and lightened, like having the steel belts replaced by carbon, kevlar of even glass fiber?
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I think the "wider is better" works regardless. Look at it this way,
If RR is energy loss - and the energy is lost in form of heat by the internal friction of the tire and the friction with the road surface plays a minimal role - then most of the heat is generated within the tread rubber, because it is both the largest mass and because it is deflected the most. Sidewalls have a much smaller mass and depending on where on the sidewall you look, they are defected as much as the tread.
That means the ply materials, such as polyester and steel don't have a very big impact on RR so replacing them doesn't result in much difference. But changing the tread rubber does.
Also, the amount of deflection is controlled by both the inflation pressure and the load. So going to higher inflation pressures gives you better RR - and going to a lighter load gives you better RR.
In fact, RRC (Rolling Resistance Coefficient), where RRC times the load on the tire = RRF (Rolling Resistance Force), is fairly linear and not dependent on how close to the rated load you are. You could be above it or below it and the RRC is still fairly linear - and for a given inflation pressure, the same value.
While as a tire engineer, I am happy that is so - keeping people safe should be my first priority - that doesn't change the laws of physics. It's just the way it works.