Surface processing (coating) the only way to reduce the coefficient of friction.

Low coefficient of friction rubber coating "IF".

"IF" Low coefficient of friction rubber coating is coating rubber surface with fluroroethylene to reduce friction.
Fluoroethylene has a slippery property, The minute particles are mixed with a special binder to hold Fluoroethylene to the rubber surface. This reduces the co efficient of friction.
In addition special primers are used to improve the poor adhesion in EPDM.