Glad to see someone else go down the same rabbit hole! The implementation is the car being a rigidbody , with several static bodies. I did try and combine the colliders into one mesh under a single staticbody but it didn't seem to help which was confusing. As you said jolt didnt help at all, I made a simple project with the issue and using the rapier physics addon fixed it in the simple project but not in my game. I did fix the issue using a characterbody3d and move_and_slide. This broke other things though like loops so wasn't worth it in the end.