Magnesium alloy wheels, or "mag wheels", are sometimes used on racing cars, in place of heavier steel or aluminium wheels, for better performance. The wheels are produced by one-step hot forging from a magnesium alloy known as ZK60, AZ31 or AZ91 (MA14 in Russia). Cast magnesium disks are used in motorcycle wheels.

The mass of a typical magnesium automotive wheel is about 5–9 kg (depending on size).

Magnesium wheels are flammable and have been banned in some forms of motorsport in the UK following fires which are very difficult to extinguish. Mag wheels have been known to catch fire in competition use after a punctured tire has allowed prolonged scraping of the wheel on the road surface.[citation needed] Some variants of magnesium alloy wheels may have low corrosion resistance.

They have the disadvantages of being expensive and not practical for most road vehicles. Aluminium wheels are often mistakenly called "mag wheels".