17" rims

[amalventano1 at tds.net (Allyn)]

> One can also expect that going from old tires to new tires will demonstrate increased grip, as a matter of course.  So, your
example can't really qualify as a good scientific, apples-to-apples comparison/test, if this is the case.
> larry

Oddly enough, newer rubber provides less lateral grip.  This is the exact reason racers take a brand new set of rubber and shave
them to 3-6 /32.  Deep tread only exists for greater foul weather traction, and because people don't want to buy new tires every 6
months.  Larger tread blocks deflect to a greater degree under cornering, causing greater slip angle, and greater deformation of the
contact patch under heavy loads.  The extreme of this is brand new rubber, which still has mold release impregnated in the outer
layer of tread.  In my prior example, the tires were as follows when tested:

195/50/15 - (sidewall 3.84) - yoko avs, ~25% tread (perfect tread depth for autox)
215/40/17 - (sidewall 3.39) - kuhmo ecsta 712, ~75% tread (mostly due to 'Anson influence')
235/40/17 - (sidewall 3.70) - kuhmo ecsta 712, ~95% tread (about a month old)

In this case the tread difference worked against the grain, yet the other variables still prevailed.  The yoko / kuhmo change also
acted against the grain, as the yokos were a much softer, stickier compound.  An interesting point is that the final size sidewall
is closer to that of the original yokos, yet there was another step increase in lateral grip, even despite the larger tread depth.

Something else to consider - for a given series / sidewall height, I believe a larger wheel still results in an overall stiffness
increase, as there is more sidewall acting about the contact patch area.  I'm not using that as the excuse to go up on wheel size,
just viewing it as a possible side effect.

Now up to $0.04 :) (good discussion though)
Al