members 14 were formed of polyester resin fibers in testing the v belts of examples 1 and 2 the belts were wound between a drive pulley having 107 mm diameter and rotating at 3000 rpm and a driven pulley having 100 mm diameter a tension pulley having 70 mm diameter was urged against the tension section 16 under a driven axis load of 80 ps 80 kg at room temperature the belts were run for 240 hours and the wear rate determined as by determining the difference in the belt weight before and after the test the results of the wear test are shown in table 2 below table 1______________________________________ comparison v belt v ribbed example examples examples a b c 1 2 3 4______________________________________chloroprene 100 100 100 100 100 100 100rubberstearic acid 1 1 1 1 1 1 1magnesium oxide 4 4 4 4 4 4 4age preventing 2 2 2 2 2 2 2agentprocessed oil 5 5 5 5 5 5 5haf carbon 35 50 35 35 35 35 35blackcut cotton yarn 20 20 30 20 20 20 20silicon carbide 10 10 10 10powder 1 silane coupling 0 5 0 5agent 2 zinc oxide 5 5 5 5 5 5 5ethylene 0 5 0 5 0 5 0 5 0 5 0 5 0 5thiourea______________________________________ 1 0 6 microns of mean particle size 2 gammamelcaptopropyltrimethoxysilane table 2______________________________________ comparison example examplebelt running test a b 3 4______________________________________1 wear rate 8.