Nissan 370Z Forum - unsprung weight

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Interesting thread. A little was over my head, but I think I got the gist of it.

Quote:

Originally Posted by totopo (Post 2531813)

what I meant was that if you vary the mass (unsprung weight), it's the acceleration that stays more constant and the force that varies. so less unsprung weight means less force for same acceleration, and less momentum and less energy, and less perturbation of chassis.

Except A = F/M. It's not really that the lighter wheels provide a lower force, the decrease in mass allows for an increase in acceleration (the same reason the car brakes and accelerates better). You will actually notice a rougher ride as the wheels' reactions to bumps will happen much faster. What also happens is a a reduction in momentum which, potentially, doesn't cause the wheel to travel quite as far initially or on the rebound stroke.

I dropped about 9 lbs per wheel in going from the Rays forged aluminum wheels on my sport Z to forged magnesium monoblock wheels from Litespeed Racing. In addition to the increased responsiveness of the steering and suspension, the suspension compliance was also increased. There is less impact shock transmitted through the suspension when I go over bumps and holes in the road, a consequence of impulse and momentum.