Renthal sr4 4 arm 104bcd chainringsr4 chain ringsingle ring 4 arm 104bcdrenthal39s chainwheels are precision cnc machined to extremely tight tolerances to give the ultimate combination of strength and light weightthe 7075 t6 aluminium alloy chainwheels are 66 lighter than steel yet incredibly durable their advanced tooth profile concentricity and accuracy of fit provide maximum power transfer and long liferenthal39s combination of a very high strength base material and an exceptional