Toyota Formula One alloy wheel

Alloy wheels are automobile (car, motorcycle and truck) wheels which are made from an alloy of aluminium or magnesium metals (or sometimes a mixture of both).

Characteristics

Alloy wheels differ from normal steel wheels because of their lighter weight, which improves the steering and the speed of the car, however some alloy wheels are heavier than the equivalent size steel wheel. Alloy wheels are also better heat conductors than steel wheels, improving heat dissipation from the brakes, which reduces the chance of brake failure in more demanding driving conditions.

Alloy wheels are prone to galvanic corrosion if appropriate preventive measures are not taken, which can in turn cause the tires to leak air. Also, alloy wheels are more difficult to repair than steel wheels when bent, but their higher price usually makes repairs cheaper than replacement and even severely damaged wheels can often be repaired to like new, though this depends on how badly the owner wishes to salvage the wheel and its intrinsic worth or availability.

For passenger vehicles, alloy wheels are not only for improved driving performance, they are also for cosmetic purposes. The alloy wheel itself is shiny and/or has an intricate design, so there is no need for paint or wheel covers. By contrast, steel wheels either have to be painted steel rims with a chromed wheel nut, or be hidden with plastic wheel covers.

Alloy wheels are more expensive to produce than standard steel wheels, and thus are not included as standard equipment on base models of many non-luxury vehicles, instead being marketed as optional add-ons or as part of a more expensive trim. However, alloy wheels have become considerably more common since the 2000s, now being offered on economy and subcompact cars, compared to a decade ago where alloy wheels were often not factory options on inexpensive vehicles. Alloy wheels have long been included as standard equipment on higher-priced luxury or sports cars, with larger-sized or "exclusive" alloy wheels being options. The high cost of alloy wheels have made them attractive to thieves; to counter this, automakers and dealers have issued wheel locks where one of the wheel nuts require a special key to remove.

A big advantage of alloy wheels is that balancing them is easy. The balancing weights are attached in the centre unlike steel wheels where they are attached at the edge of the rim. Thus wheel balance is not disturbed by tyre removal, etc.

There are different types of alloy wheels. Some are cast, which are the most commonly seen on the road, while others are forged. Forged wheels are lighter and stronger, yet much more expensive then cast alloy wheels. Forged wheels are typically purchased by enthusiasts, luxury/sport vehicle owners, or the affluent.