MvM said:
The weight of wheels and tires is unsprung weight, meaning that it is not held up by the car's suspension. The body of the car is sprung weight. The question is, how many pounds of sprung weight does a pound of unsprung weight translate to? I have heard claims that one pound of unsprung weight is equivalent (in terms of its effect on acceleration) to anywhere from 1.4 to 8 pounds. I tend to believe the smaller numbers.
MvM said:
In terms of sheer weight, yes. But then you have to take into account the rotational moment of inertia, as Jimbo mentioned. Basically, the further the weight is from the center of the wheel, the greater the impact (in other words, the more pounds of sprung weight it translates into). This is just like with a child on a see saw (teeter totter), where the further he is from the center, the more force is needed to raise him.
Also, there are other effects on acceleration with the larger wheels, including the fact that the tires tend to weigh more, and the possibility (depending on the tire size chosen) that the tires may have a larger outer diameter which could hurt effective gearing.
yay
