If you know the true length, width, and type (IE: Ribbed, V, cogged, etc.), and actual width of each rib, if McMaster Carr does not carry 1 that size, they will make it custom. For same prices as if they stocked it. Had same issue recently switching my water pump over to elect. Based drive and then needed a 6 rib to use just Alt. on the crankIt is a Gates number and so far I am not finding a lot of information on Gates timing belts, still looking.