[glenview289]

Aluminum (6061 alloy) weighs 2720 kilograms/cubic meter and Magnesium weighs 1738 kilograms/cubic meter or 36.1% lighter than Aluminum. That percentage could vary depending on what alloy and how much of it is needed to cast the two materials. It is also possible that the cross section of one of the wheel materials may need to change to achieve the same strength and therefore also affect the weight difference. I think that if the Magnesium wheels were always available, regardless of any weight advantage, you would see a lot more of them because they are just another one of the cool and unique features of these cars.

Bill