Some low grade and less expensive gym pulleys are made of plastic and have a bushing in the center where the support bolt passes through, but better pulleys are made of fiber glass reinforced nylon and have bearings in the center. Some are made of metal. Most of the better quality gym pulleys last for years and require no preventive maintenance other than inspection.

Even the best gym pulleys sometimes get chipped, cracked or chewed up at the outside edges. These deformities usually are a result of misuse of the gym equipment by allowing the weight stack to travel too far up the guide rods and coming into contact with a pulley. Over a period of time, the roller bearings built into the center of the pulley can wear out, causing a rough feel to the weight movement or making the pulley wobble. A wobbly pulley can cause a cable to derail and get damaged, thereby making the gym cable unsafe to use.

Sometimes, with wear, the channel in the pulley, where the cable rides, gets rough and can ruin the sheathing on the gym cable. This is most often caused by using a pulley with a partially frayed cable or one that is missing part of its protective sheath.

Periodically inspect your gym's pulleys for damage or wear. If you find any defects, replace the defective pulley before it damages the associated gym cable.

If you need to find a replacement pulley, knowing the brand and model of the gym that the pulley is on will help you to get the correct replacement. However, all too often, by the time the pulleys wear out, the manufacturer of the gym is out of business. If that is the case, when you are ready to order a replacement gym pulley, you will need to know three things about the pulley: the diameter, the bore ( basically, what size bolt passes through the hole in the center) and approximately how wide the pulley is at the center.