Why have magnesium wheels disappeared from the street?
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Why have magnesium wheels disappeared from the street?
I'm showing my age, but ultra-light Campagnola magnesium wheels were an option on my Fiat (my brother still has the car and wheels). Today, I think pure race cars are about the only place you can find them.
I realize that magnesium dust is readily flammable and can make a nasty fire (so can gasoline), but a solid chunk of metal is almost impossible to ignite. Are magnesium wheels not used on the street because of potential corrosion problems?
Compagnolo wheel on a Fiat
<img src="http://europeancarweb.com/features/0408ec_fiat04_z.jpg">
I realize that magnesium dust is readily flammable and can make a nasty fire (so can gasoline), but a solid chunk of metal is almost impossible to ignite. Are magnesium wheels not used on the street because of potential corrosion problems?
Compagnolo wheel on a Fiat
<img src="http://europeancarweb.com/features/0408ec_fiat04_z.jpg">
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Mg wheels are not ideal for street or everyday use...more
fallzboater is correct, once a mg wheel is scratched or damaged, it will need to be polished right the way, if not, it will oxidize. They are also more fragile than Al alloys, the only advantage to them is that they tend to be lighter.
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Forged aluminum = almost as good, very low corrosion or fracture risk.
Magnesium experiences stress fractures over time.
This is its biggest weakness.
Corrosion of the wheel's finish can raise the risk of fracturing the wheel.
This is why magnesium racecar wheels are routinely x-rayed for fracture.
OZ still makes a ton of magnesium wheels, some of them for street applications.
Very few cars come with magnesium wheels standard.
They are/were options on the TVR Cerbera Red Rose, Lotus Exige, and NSX Type R...
As for weight, here are some stats:
Lotus Exige Standard Wheel (forged aluminum)
Front: 15.17 lbs
Rear: 20.94 lbs
Lotus Exige Lotus Sport Lightweight Wheel (forged aluminum)
Front: 12 lbs
Rear: 14 lbs
Lotus Exige Cup wheels by Dymag (magnesium)
Front: 10.8 lbs
Rear: 13 lbs
The weight savings just aren't there to justify the exotic materials, especially with the longevity issues facing magnesium wheels.
This is its biggest weakness.
Corrosion of the wheel's finish can raise the risk of fracturing the wheel.
This is why magnesium racecar wheels are routinely x-rayed for fracture.
OZ still makes a ton of magnesium wheels, some of them for street applications.
Very few cars come with magnesium wheels standard.
They are/were options on the TVR Cerbera Red Rose, Lotus Exige, and NSX Type R...
As for weight, here are some stats:
Lotus Exige Standard Wheel (forged aluminum)
Front: 15.17 lbs
Rear: 20.94 lbs
Lotus Exige Lotus Sport Lightweight Wheel (forged aluminum)
Front: 12 lbs
Rear: 14 lbs
Lotus Exige Cup wheels by Dymag (magnesium)
Front: 10.8 lbs
Rear: 13 lbs
The weight savings just aren't there to justify the exotic materials, especially with the longevity issues facing magnesium wheels.