I guess I need to clarify my argument on 15 vs. 16.
First off, it was done based on either a 245/50-15 Hoosier Radial or a
245/45-16 Hoosier Radial. That's what this was based on, but the
argument is still valid for a different tire.
As I said before, the rolling diameter of the two tires is same:
245/50-15 : 24.2 in
245/45-16 : 24.2 in
Hence, the mass of the 16" tire is lower due to less sidewall material.
245/50-15 : 19.5 lbs
245/45-16 : 18.5 lbs
The mass of a 15x9 compared to a 16x9 common racing wheel (real, keizer etc.):
15x9 : 14 lbs
16x9 : 15 lbs
What happens is that the mass of the assembly moves inward. Partly in
the extra 6 inches of rim (54 sq in) that the 16s carry, and partly in
the extra 97 sq in of aluminum center material. But, the fact remains,
the overall rotational inertia of the wheel has been reduced without
reducing the mass of the whole assembly or giving up other changes. The
other benefit, is a more responsive handling effect from the shorter
sidewalls of the 245/45-16.
-Josh2
--
Joshua Hadler '74 914 2.0 CSP/Bi - Hooligan Racing #29 - CONIVOR
'87 Quantum Syncro - aka stealth quattro
jhadler@rmi.net
http://rainbow.rmi.net/~jhadler/
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