I’m pretty new with ACF, but I’ made a bunch of vehicles with it so far. One thing they all have in common is that if any of them have a gear ratio that gives them enough torque to go up hills their wheels twitch and fall through the ground (mostly when going up hills). I’m using the SProps A and B wheels as well as PHX’s Off-road wheels. If I make the wheels heavy they don’t do it, but they also once again don’t have enough torque to go up hills. Making the base prop heavier doesn’t help (same with making it lighter). Also, I tried using the wheels with Make Spherical, and it did not help at all (maybe a bit worse actually).