You guys that use spacers, did you happen to measure wheel well gap before and after?

Spacers increase the overall effective length of the lower control arm, thus motion ratio, a wee bit and and I wondered if y'all noticed any drop after installing them.

Motion ratio is the difference in travel of the wheel and the spring. MacPherson strut cars have the lower spring perch almost on top of the hub so the difference between wheel motion and spring motion is almost nothing, that is a motion ratio of ~1:1. Push the wheel up one inch and spring travels almost one inch.

Our cars have the spring seat much closer to the lower control arm pivot, the motion ratio is closer to 2:1. Move the wheel up one inch and the spring compresses only about a half-inch. The larger the distance between the wheel and the control arm pivot for a given lower spring perch location, the high the motion ratio. This in effect makes the spring softer in that there's a longer lever arm working on the spring.

An example of this is "true" coil-over application in the rear of the G. Most coil-overs use the stock rear spring location and thus will have rear spring rate of 10-12kg/mm or higher. "True" coil-over has a significantly lower motion ratio since the spring is mounted around the shock, so it's further outboard than stock thus the spring rate is correspondingly lower, more like 6kg/mm.

So, any measurements?