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Old 03-08-2018, 10:36 AM   #11 (permalink)
ksa8907
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Quote:
Originally Posted by RedDevil View Post
By the way, there should be no difference in distance reported between new and worn tires, even though the new tires have a slightly larger circumference.

Amazing, no?

Consider this: A tire on a car is not a perfect circle. The contact patch is flattened out, and there the tread shrinks; the grooves narrow as the lugs get squeezed together.

By and large the distance a wheel travels with each rotation is the same as the length of the steel belts in the tire. The distance between the belts and the tread surface has no influence; again, the contact patch is flat.

Actually, if anything it is the other way round.
As my tires wear I see a very gradual reduction in the reported distance of my commute on the odometer. The same route that was 35.6 km when the tires were new now takes just 35.4 km.
I bet the belts have been stretched ever so slightly.

Worn tires slightly underreport the mileage.
So you're saying a smaller diameter tire has magical properties and actually travels a greater distance with each revolution?

The tire obviously deforms when in contact with the road, inflation pressure will play a large role. In order for a smaller diameter tire to travel the same (or greater) distance would mean the tread on the larger tire is being compressed much more than the smaller tire. How?

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