[You know you're proud to be a FIRSTer when...] You explain to someone how do do something, they go off and do it, come back and ask, "is this right?" and you say,
"Yes."
. - NorviewsVeteran [more]
Centrifugal force is causing the rubber to expand due to the high speed. You could try one of the Blue compound ones or slowing it down.
Sorry if this seems kinda out there, but it's Centripetal Force that causes the rubber to move outwards tangent to the direction of rotation. Centrifugal Force does not exist.