Flywheels are what creates the resistance for the Quest line of products. Flywheels are completely interchangeable between product models. Flywheels are sold in a variety of sizes to accommodate different resistance ranges. Flywheels can be combined to allow more resistance options, or to increase resistance beyond the use of a singe XL wheel. Flywheels are made from solid steel and finished with a thick layer of powder coating. Grooves on the face of the wheels provide a griping surface to allow for easy loading onto the quest line of products.