As opposed to steel wheels, aluminum wheels are typically much stronger and have the ability to withstand more stress than steel wheels. Aluminum wheels are also easier to care for and will normally retain their original appearance better in the long run. Aluminum wheels also weigh less than their steel counterparts.
Typically, aluminum and aluminum alloy wheels are manufactured in as either a single unit or one piece, or multiple unit which will consist of up to three separate aluminum pieces. A single-unit wheel is cast in a mold which includes all features of the wheel necessary for function. A three-piece wheel, for example, will usually consist of an inner and outer wheel piece and an additional center or barrel piece. These pieces must be securely welded or bolted together to ensure they are sufficiently strong to withstand the forces of operation.
There are essentially three types of manufacturing processes used in the manufacture of aluminum wheels. Forging is an excellent technique for making aluminum wheels and involves the compression of a solid piece of aluminum, or billet, into the desired wheel design. This process results in an extremely strong and durable wheel. With rolled forging, aluminum sheets are rolled through heavy press wheels which imprint or stamp the aluminum with the wheel design. This process uses less aluminum than normal forging. Casting utilizes melted aluminum and is either poured or drawn into molds of the desired wheel design. The poured method is referred to as low-pressure casting while the drawn method is referred to as counter pressure.
