Tried this today and the i-hooks ripped out of my newly bought hard balls. They were pretty substantial i-hooks. The rubber in the hardball's didnt hold and the whole think cost me at least 15 bucks. The balls do say little league on them so I am wondering if big league balls are made with wood core rather than rubber. They felt the same.
Is there a tip I am missing so these can support my full weight without ripping off the hooks?
Use an I-bolt, drill all the way through the baseball with a drill, and then use a wide washer or two along with a nylon locking nut to hold it. I weigh about 290 right now and have several baseball (and softball) pull up grips I use all the time with no problem. The screw in hooks will rip out no matter what.
The biggest room in the world is the room for improvement.