After all these years I finially figured out belt lengths. The B-55 or whatever size is on the belt is not the OD or ID of the belt. It is the pitch length which is the length the largest diameter of the pulley is touching the side of the belt. Several belt sites state the OD is 3 inches longer then the marked length. I find 2-1/2"s longer is closer. The ones I measured were 2-3/8" longer then the "B" number but I will go with the 2-1/2"s. The surface across the top of the belt is not always flat, some have a crown so these measurements are only close not down to the 1/16". Also the best way to measure a belts OD is to roll it on a flat surface, I put a mark on the side of the lift, marked the side of the belt next to the "B" and rolled the belt down the lift and marked the lift when the "B" mark came around, then check it again. Then measure between the lines. If you come up with 48-1/2"s you need a B-46 belt. Some will say "B" belts don't work but I have used several hundred over the years and I never had a problem with them. G.M.
Fan belt length
- Thread starter G.M.
- Start date
34fivewindow
Senior Member
GM, this is some good INFO, i also use the B belts, get them from a bearing supply house.....Ed