Needed to order a Vee belt for my alternator with AC and wanted the alternator to sit tight to the thermostat housing. I came up with what I think is the perfect measuring tool. I used a 1/2” (13mm) plastic banding strap and cut it to the exact length which was 31” or 787mm. I ordered the closest belt at 785mm and it fits like a glove. The banding strap was perfect because it fit the sheaves without sliping around and doesn’t stretch at all.