How do you measure a serpentine belt with no part number on it?

Would you measure the inside with the ribs or the backing of the belt? Should it be measured on or off the pulleys? What would you use to measure the length of the pulley – a string, ruler or tape measure? Do you measure the outside or inside circumference of a multi-ribbed belt?

If you were to talk to a belt engineer, he or she would tell you that they call the measurement the effective length, and it’s measured at the cord line. If you talk to a catalog specialist at a belt company, they would tell you the effective length of the belt is part of the part number. For example, this Continental OETS Automotive Multi Rib V-belt has part number 4060805. The last three digits in the part number indicate the belt has a length of 80.5 inches.

This video is sponsored by Continental.