Why do racers prefer magnesium alloy wheels and what makes these wheels superior? Let’s have a detailed look at the unique properties of magnesium, the lightest metal used in the automotive industry. Although magnesium wheels have been around since the middle of the previous century, the potential of Mg remained largely untapped for decades after. Among all metals used in production magnesium shows the best strength-to-weight ratio. Components made of magnesium alloy weigh on average 30% less than aluminum ones, for example, while maintaining equal strength. Of course, such wheel weight reduction makes a noticeable impact on a vehicle’s performance, but this is not the only factor to consider when you are shopping for alloy rims to be used in daily driving. Safety, overall look, quality of a ride and longevity are equally important.
Extending the lifecycle of magnesium parts
The first magnesium wheels took the world by storm in the mid-1950s but their popularity faded quickly as they were prone to corrosion and therefore impractical for street use. Regular city drivers switched to aluminum alloy wheels, despite the fact that they were heavier and had a negative impact on performance. But the obsession for magnesium wheels did not just disappear — they remained popular among racers and auto enthusiasts, so some brands such as Minilite managed to survive and thrive from the 1950s until now.
The real breakthrough occurred in the beginning of the 21st century when new powder coating techniques were developed, with the result that modern magnesium alloys with high-quality coatings are superior to aluminum counterparts in corrosion resistance and many other characteristics. This discovery paved the way for applications of magnesium alloy parts in the aerospace industry, where weight reduction, safety and durability are the key criteria.
Increasing safety of magnesium alloys
Another major improvement to magnesium alloys was made around the same time. Because pure magnesium is flammable, some safety experts expressed concerns about the possibility of Mg wheels igniting as a result of prolonged scratching. But this possibility doesn’t seem to be a factor when magnesium is used in an alloy: magnesium wheels have been used for racing, including in such high-speed competitions as Formula One, for over 60 years and there is no fact-backed evidence of them catching fire on the road.
In recent years magnesium alloys have become even safer. Adding 1% of calcium and other additives not only makes catching fire impossible, but also helps the alloy withstand very high temperatures. This means that even if a car or plane catches fire, the magnesium alloy parts most likely won’t burn. As a prime example, the U.S. aviation safety watchdog, the Federal Aviation Administration, did not rush to allow magnesium alloys for use in aircraft cabins, but after numerous tests the FAA has acknowledged that seats made of modern magnesium alloy show the same or even better fire resistance than aluminum ones.
Advantages of modern magnesium alloy wheels
Besides major safety and longevity advantages, magnesium wheels provide other specific benefits for a car and its driver. Faster acceleration and shorter braking distance can both be realized, as lightweight Mg wheels can provide weight savings of 24 kg or more*. Lighter wheels require less power to start and stop rotating, which leads to less fuel consumption, especially in a city driving mode where frequent stops and starts are the norm. Less fuel consumption means reducing the carbon footprint of auto emissions, which is good for the environment, so magnesium alloy wheels contribute to improving the ecology as well.
Magnesium has more unique properties also deserving of mention:
- Outstanding Damping Capacity
Damping capacity is a material’s ability to absorb vibrations. When a magnesium wheel hits a road pit the vibration is transmitted into the air, reducing pressure and prolonging the life of the suspension system, as well as creating less discomfort for the driver and passengers.
- Excellent Ductility
Ductility is the ability of a metal to deform under stress. Wheels made out of magnesium alloy tend to bend in an accident without cracking, and can thus be more easily repaired.
- Superior Heat Dissipation Capacity
Magnesium alloy wheels help the brakes cool faster and prevent overheating, which is especially important if emergency braking is required at a high speed.
Magnesium wheels can be crafted in any number of designs and styles to suit a driver’s taste. These are of course a matter of personal preference. But from a purely practical aspect, all of the benefits mentioned above undoubtedly make magnesium wheels a smart investment, especially if you opt for wheel sets that come with an extended warranty (such as 10-year warranty from SMW Engineering).
*According to calculation provided by magnesiumwheels.com for Porsche 911