Pickup Liftgate bumpers

I needed new bumpers on my trucks liftgate but didn't want to pay almost $40 for a set just like the ones that had already came off. So I designed some rounded ones then decided I wanted them to have more of a flat surface for even more support.

Sometimes I pick up full drums from a shop with nice sealed concrete floors so I don't want to damage the floors sealed surface with a bare metal gate scratching the floor surface

A 1.5" OD fender washer fits snugly inside. The bumpers thickness be