Why magnesium-alloy wheels? Simple really – magnesium-alloy's two-thirds as dense as aluminum, but has similar strength, so you can have a lighter wheel. But magnesium's more susceptible to corrosion damage than aluminum, and expensive, so has traditionally been restricted to high-end race wheels.
But currently we see more and more affordable magnesium-alloy wheels on the market. Most of them come with powder-coated finish, with a chemical coating underneath to reduce corrosion, and come in many different colors. Most of this aftermarket magnesium-alloy wheels are brand and model specific and come with sprocket carrier, bearings, internal spacers and cash drive. The disc mounting bosses are screwed onto the hub to make a universal front hub with different bosses to suit different motorcycles.