We race on a school netball court and it has a big crest in the middle and a few dips and bumps, and also we used flat boards to lay out the track, the car was over 6mm last meet (the ride height gauge wasnt near touching) tho that was measured without a battery in the car, and the car still got some new scratches on the bottom - tho i suspect they are more from the track boards anyhow... will go out tomorrow and do some testing before sundays racing if i get a chance