The Roll-Line BOXER 55mm Introductory FreeStyle Wheels provides an entry level to high level Competitive Skate Wheels. The Roll-Line BOXER can be used on many types of skating surfaces including standard wood floors coated with plastic or poly urethane, but also unusual surfaces like, tile type basketball and volleyball courts, tennis courts (Indoor or outdoor), and concrete or terrazzo surfaces that are more common around the World. The Roll-Line BOXER Wheels are a MonoCompound Elastomeric ThermoPlastiche wheel, which is produced utilizing an injection system. The softer the wheel, or lower Shore D hardness number, the more the grip and slightly less roll. The harder the wheel, or higher Shore D number, the more the roll, with slightly less grip. It is almost always recommended to use spacers in the wheels, when using standard 7mm bearings. Long ago, before the use of Lock Nuts (the nuts that have the Nylon Plastic inserts) to hold the wheels on the axles, Jam Nuts were used, but when the spacer was not as wide as the web of the wheel, or the wheel was not machined accurately, the bearings would lock up, the nut had to be tight, and could not be backed-off. This method, of locking the Axle Nut down, did promote proper bearing alignment and did increase the diameter of the axle from 7mm to approximately 14mm, because everything was locked down, which also saved the problems of bent axles. Today we do use Lock Nuts. It is still very advisable to lock everything down (especially for FreeStyle, Jam, and Roller Derby Skaters). Roll-Line does provide Spacers for Roll-Line Wheels with each pair of Frames or they can be purchased separately. Properly locking the Wheels down when using standard bearing types, will also promote longer bearing life.
