Ta shimano 130mm 8910 speed compatible 7075 t6 heat treated aluminium polished silver or blackta only make their chainrings from the best 7075 t6 heat treated aluminium sheet the teeth are cut in the traditional manner on a lathe which produces a much better and more accurate tooth form than pressing which is used by most chainring manufacturers the 38t to 46t are only designed to be used as an inner ring on a double chainset can not be used as a middle ring on a triple chainset as the