V-Belt Performance Checklist

The speed of your drive system, its load, and its hours of operation all contribute to the frequency of belt replacement, but the performance and longevity of your V-belts depend largely on steadfast maintenance and correctly recognizing and diagnosing issues. Most common issues can be easily seen or heard, and we’ve put together a list of some of these symptoms and their causes.


If… Then…
V-belt is slipping or squealing The most likely cause is either worn sheaves, not enough tension, or both. You should inspect the sheaves, measure the tension of the belt, and check for excessive grease or moisture.
Underside of V-belt is cracked Undersized sheaves, excessive heat, or incorrectly installed backside idler may be the root cause.
Cogs of belt are missing Similar to a cracked V-belt, this may be caused by incorrectly sized sheaves, excessive heat, or an incorrectly positioned or sized backside idler.
Sidewall of V-belt is wearing rapidly This is most commonly caused by worn or damaged sheaves. However, you should also check for insufficient tension, sheave misalignment, excessive grease or moisture, or simply that you’ve got the wrong type of belt.
V-belt is soft and swollen A soft or swollen belt is likely caused by excessive exposure to grease or possibly belt dressing. If you are using large amounts of belt dressing to combat squeaking or squealing, refer to the first item on this list.
Bottom surface of belt is worn This is most likely caused by shave wear, causing the belt to bottom out against the sheave grooves. Debris in the sheaves might also be the culprit, but in either case the sheaves should be inspected.


Wear on V-Belts can occur on all sides and corners of the belt. By identifying the location of the wear on the belt, and then reviewing its contact points with the sheave, guard, or idler, you should be able to spot the issue.

When it does come time to replace a V-belt or sheave, be sure to browse our wide-ranging inventory and order online.