A power transmission belt with a body made from a first rubber composition in which at least one load carrying member is embedded. The body has a plurality of laterally spaced ribs with exposed surfaces on the inside of the body. The ribs are made from a second rubber composition in which: a) a plasticizer of 8.3 to 10.7 (cal/cm3)1/2 in solubility parameter; and b) solid lubricant are respectively blended in an amount: i) 5 to 25 pts.wt.; and ii) 5 to 50 pts.wt. per 100 pts.wt. ethylene-α-olefin elastomer. The body further has short fibers fixed at the exposed, pulley engaging rib surfaces.