I have the same problem. I have the alpinestar rib protector and a free line seat. I went out with too much rear grip and cracked my ribs. I was snug in the seat and felt okay but just did not feel perfect. So i’m back at the beginning and don’t know what to do my ribs fucking kill me. I have been karting for 13 years and stock cars for 8 and i feel like a nub!!!! I DON’T KNOW WHAT TO DO!!!!!