[QUOTE=mans;276589]
Quote:
Originally Posted by Ken Fry
on tread shaving these are pretty good the tread is only 2.75" wide
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You don't shave the tread to make it narrower. When you shave the tread, you make the tread thinner, so where it used to be 1/2" thick in the middle it becomes 3/8", etc.
The tread bends as it flattens onto the road, and then straightens when it leaves the road. This bending absorbs energy, and therefore the tire heats up. If the rubber is high hysteresis (not bouncy) a lot of energy is absorbed, (and relatively little is returned) and other things being equal, the tire rides better and is quieter, but less efficient.
In a low hysteresis tire, a larger part of the energy required to flex the tire is returned when it unflexes as it leaves the pavement. This makes the tire bouncier, but more efficient.
As you can imagine, a thicker tread is harder to flex, so absorbs more energy when it flexes, and (especially if high hysteresis) returns less when it unflexes.
Bonneville cars used to shave the tread on tires for these reasons -- both to use less energy (to make the car faster) and to generate less heat (tires convert wasted energy to heat) so the tires don't overheat (and also to reduce centrifugal force).
If you compare tread depth specs on the tire sites, you'll find that Low rr tires often have thinner treads for the above reasons.