Forged Elektron AZ80 magnesium alloy racing wheel, which is significantly lighter than aluminium (6 kg per wheel). Magnesium wheels are either gravity die cast or forged. Forged wheels have superior mechanical properties and the wall sections may be thinner than with casting, resulting in lighter wheels. The drawback of magnesium generally is the relatively poor corrosion resistance and resilience, so they tend to be only suitable for short term use, such as racing wheels. Image by Luxfer.