Cracking/Chunking/Wear

Under severe operating conditions (high temperatures, low humidity), drive belt rib cracking can occur at less than 160,000 km (100,000 miles). Drive belt rib cracking (cracks across backing):
^ is not a reason for concern.
^ has no detrimental effect on drive belt performance. However, cracks running with backing are not acceptable.





The drive belt (8620) is still perfectly functional until rib chunking occurs. Drive belt chunking is where the rubber material actually chunks out between the cracks. The drive belt should be replaced if the chunks are 5 mm (0.019 inch) or longer.





Cracks on the rib side of a drive belt are considered acceptable. The drive belt should be replaced if two or more adjacent ribs have lost sections 13 mm (1/2 inch) or longer, or if the missing sections are creating a noise/vibration/harshness condition.