Quote:
Originally Posted by BGM
In some aspects, 20s will not perform better than the 19s because of weight but not in terms of stopping feet and skidpad tests (below). Stopping feet is an every day driving occurrence and so is handling (skidpad more related to higher speeds).
Car and Driver:
X5 non-20s:
Braking, 70-0 mph: 169 ft
Roadholding, 200-ft-dia skidpad: 0.82-g
X5 20s:
Braking, 70-0 mph: 159 ft
Roadholding, 200-ft-dia skidpad:: 0.87-g
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These numbers would make sense given that the 20s wear wider rubber, meaning a larger contact patch with the pavement (thereby a higher friction coefficient between the vehicle and the pavement) which will result in better stopping and skid pad performance if everything else is essentially equal.
Also, on a 5000lb vehicle, the effect of the heavier 20s is less than on a lighter vehicle in these types of tests.