Ideal Security's nylon garage door rollers are perfect for replacing old, worn, noisy, or broken rollers. Garage door rollers are easy to replace yourself. Premium nylon & Steel wheels with 10 ball-bearings. Standard wheels are made of solid nylon and wear out, but steel wheels can be noisier. These premium wheels have nylon shells for the quitest possible operation, and steel cores for durability. They are the top-of-the-line in garage door rollers. Each roller contains ten ball bearings for smooth operation. These 2-inch wheels fit the standard 2-inch tracks on most residential doors. The 4-inch stem is suitable for standard single-hinge installations. The stem slides into the hinges on the outer edge of the door. The average residential garage door has 10 rollers on it. For smooth and easy opening and closing, and to extend the life of the electric door opener, change all rollers at the same time or when adding a new electric opener.