Quote:
Originally Posted by Swiftbow
Interesting Capri. How is a load indices calculation performed? ........
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Load Index is a quick, and easy way to express load carrying capacity.
There are several formulae for calculating the load carrying of a tire, but they are complex - and of course, it varies accoprding to inflation pressure. Usually load carrying capacity is published in the form of a table.
I explain that in more detail here:
Barry's Tire Tech
Quote:
Originally Posted by Swiftbow
......The focus is a fairly light car so I was surprised that this tire wouldn't have the load capacity.........
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I explain that also in the link, but the short version is "Over-design / Under-utilize" - meaning you should use tires (and other products) at less than their maximum capacity - and the further away from the maximum you are, the safer it is.
Quote:
Originally Posted by Swiftbow
.....I'm also surprised that even with the tire filled to max it would give deformity degrading FE. 195 to 155 width is a substantial amount where deformation of that magnitude is surprising. BUT I really don't want to compromise safety, especially in a situation where I could harm someone else in what in the scheme of things ... is just a simple test.
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Doug
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The rolling resistance of a tire is directly proportional to its deflection, so ANY deflection has a consequence on fuel economy. And changing tire sizes changes the deflection. When it comes to fuel economy, going a smaller tire is the wrong direction. Larger tires (meaning larger load carrying capacity) have lower RR for a given load. However, this effect is pretty small and huge improvements should not be expected.