Thank you both for your replies to my question.
Regarding "thrust on the drive train"....not sure what you mean.
The skaters are just standing still while the platformn is spinning.
I registered as a 'student' because that was the only category I could choose.
I'm actually a retired pipefitter who is attempting to build a spinner platform for ice skaters to train on.
I have a 20 inch spinning platform that will support over 300 lbs.
I need to know what siz rubber drive...