how much of a difference in track times would there be if i put lets say 16's on my car i know the speedomoter would have to be recalculated but i am just wondering

 

anybody

 

It's not rim size alone, it's rim size + tire size...so it would depend on tires. Also depends on the weight of the wheel too (rotating mass) a smaller but heavier wheel has the potential to make you slower instead of faster.

 

Yup. Overall diameter and weight are the two key players. (also weight distribution on the actual wheel itself, but thats hard to measure)

If I were you I'd shoot for a light 16" wheel.

 

15" 4