Mcgo101

Hey folks just being a nerd and looking for info. My 17 enkei waffles are 24lbs ea and the kumho ecsta ps31s are 23lbs per tire. So 47lbs per corner. My question is how much will a 19lb Rim set up effect acceleration compared to a 24lb Rim? Thought I read somewhere that each lb of rotational mass reduced approximately equals 20lbs less of curb weight, is there any truth to that? Does a lighter Rim actually help with acceleration? And if so does the same go for a lw fw? Thanks!

csmeance

you can read more about it by looking up moment of inertia for a hollow hoop around its central axis.

In short. I=MR^2 -> I being inertia, M being Mass, and r being radius.

Convert R into feet and plug:
24x (17/12)^2 = 48.17 lbs/ft

You switch to 19's that are 24lbs

24x (19/12)^2 = 60.16 lbs/ft

Almost a difference of 12lbs of force to get the wheel moving from a stop on just the rim alone (not factoring in tire at all). The big issue is that more weight of the tire is moved further from the center thus requiring more energy to turn the wheel.

This is very generalized math, we can be more accurate if we factor in the inner and outer size of the rim and tire combo to account for some weight distribution over the entire sidewall height vs just using the rim.