Abstract: A power transmission belt comprising a body comprising a first elastomeric material and having tensile members running in a longitudinal direction, the body having a pulley engaging region having a profile; characterized in that the pulley engaging region comprises a surface region and a subsurface region; the subsurface region comprising a second elastomeric material having a friction modifying agent; and the surface region comprising a nonwoven fabric material co-mingled with the second elastomeric material.

Abstract: A torsional vibration damper or other vibration damping device with a rubber vibration absorbing element. The rubber element is a peroxide-cured composition comprising 100 parts of ethylene-alpha-olefin elastomer, and 20 to 100 parts of substantially isobutylene or butene polymer having a viscosity average molecular weight greater than about 5000. The polymer may also be a copolymer of isobutylene and isoprene. The addition of the isobutylene polymer to the ethylene-alpha-olefin elastomer composition increases the vibration damping character of the rubber.