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Old 11-19-2009, 10:17 AM   #4 (permalink)
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What isn't clear in the thread mentioned above is that it isn't tire diameter that has the effect on RR.

It's load carrying capacity - which, if you hold everything else the same (which you can't), is what happens when you only increase overall diameter.

Here's an example of the problem:

P205/70R15: To increase the diameter, you'd have to increase the aspect ratio = P205/75R15. That also increases the load carrying capacity - which is a factor for RR.

BUT - the largest factor is the amount of rubber and the rubber compound itself. A different tire can have a much larger effect than a change in tire size (and load carrying capacity!) The problem is the RR doesn't come without a price to pay: traction (especially wet traction) and / or wear.
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