Alloy wheels and aluminum wheels are frequently interchangeably used terms which create confusion on their differences.
Strictly speaking, alloy wheels can be made of different alloys and can consist of magnesium alloys and aluminum alloys.
Magnesium wheels are made especially for sports cars for high-performance applications.
Aluminum alloy wheels are more commonly used in vehicles and most auto manufacturers are now selling their cars fitted with aluminum alloy wheels.
The current article discussed the features, benefits, and limitations of both magnesium alloy wheels and aluminum alloy wheels and the different methods used in their production.
Magnesium Wheels: Features and Benefits
Magnesium alloy wheels were the first die-cast wheels manufactured.
These wheels are also known as mag wheels.
Magnesium wheels are manufactured from magnesium alloys by using either forging or casting method.
Forging method of wheel manufacturing uses a technology where a pre-fabricated bar is deformed mechanically using a powerful forging press.
Under the casting method, molten metal is introduced in a mold which solidifies later.
The forging method helps to manufacture many superior wheels compared to the casting method.
The benefit of cast wheels is that they are more affordable than forged wheels.
However, cast wheels are heavier than forged wheels and also less durable as they tend to fracture on high-speed impact, whereas forged wheels will only bend.
Cast wheels can have some manufacturing defects which may include cavities or porosity and a different metallurgical microstructure.
Forged magnesium wheels are at least 25% lighter than the cast wheels.
Due to their lightweight, they offer better fuel efficiency also.
Forging is a better technology for manufacturing wheels than casting.
Forged magnesium wheels have better alignment of metal fibers and optimized directional patterns along the spokes of the wheel.
They also have a smaller grain size.
These features of forged magnesium wheels, making them perfect for use in motor racing and for high-performance vehicles.
Magnesium wheels are much lighter than aluminum alloy wheels.
A typical 20-inch, 10 spoke cast magnesium wheel will weigh 10.2 Kg compared to 13.5 Kg for cast aluminum alloy wheels.
The same wheel size manufactured by forging process will weigh 7.4 Kg for magnesium wheels and 9.3 Kg for aluminum alloy wheels.
This helps to improve the fuel efficiency of the vehicle.
According to estimates, if the weight of rims, tires, or brakes is reduced by only 1% of the total vehicle weight, it will lead to an increase in fuel efficiency by 4%.
The lighter weight also means more responsive steering and handling of the car.
However, due to being lightweight, magnesium wheels need to be rebalanced throughout their lifespan.
These wheels are less likely to fracture when they are subjected to high-speed impact while driving.
Magnesium wheels have better heat dissipation than the aluminum alloy wheels.
Due to their inherent properties and are designed in a manner that they are able to distribute the heat generated from the brakes more efficiently than aluminum alloy wheels.
The better heat dissipation feature of magnesium wheels mean that you will be less likely to face technical problems in your car due to overheating, which can affect the brake pads and other braking systems.
The lesser heat due to better heat dissipation also ensures that the tires are not subjected to high levels of wear and tear and hence they last longer.
Magnesium wheels are known to provide excellent visual appeal to your cars.
You can customize these alloy wheels according to your requirements to make your wheels and car stand out from the competition.
You can make use of customization options like adding chrome or colored valve caps to enhance the visual aesthetics of your wheel further.
Due to being so desired and having excellent looks, magnesium wheels are also targeted by thieves frequently.
Hence, you will need to take proper protective measures while using magnesium wheels in your car for ensuring their safety.
Magnesium wheels are very costly.
They are much costlier than their aluminum counterparts.
The cost of these wheels is a major barrier for their usage in commercial vehicles on a larger scale.
The use of magnesium alloy wheels is restricted largely to sports racing cars and high-performance vehicles.
Prolongs the Lifespan of Suspension System
Magnesium alloy wheels have a higher damping factor which provides many benefits.
It leads to better absorption of vibrations, shocks, impacts, and noise which helps to prolong the longevity of your car’s suspension system.
These features not only provide longer lifespan to the suspension, but it also enhances drive quality, comfort, and fuel efficiency.
Drawbacks of Mag Wheels
Despite the many advantages which magnesium alloy wheels have to offer, they also come with few drawbacks.
The major limitation of using magnesium wheels are as follows:
- High Cost: Perhaps the biggest drawback of magnesium alloy wheels is their high price. They are much costlier than the regular aluminum alloy wheels. Magnesium alloy wheels do not offer value for money for the feature they provide to customers who use their vehicles for street use only. These wheels are used generally only by sports cars for racing purpose.
- Inflammable: Magnesium wheels have another drawback of being inflammable. They have also been banned in some areas of motorsports in the UK, due to the occurrence of fires. These fires can go up to very high temperatures, are difficult to control, and can become fatal for the driver. The major reason for the fire is when the tire gets punctured and the wheel scrapes against the road for a long time.
- Difficult to repair: Magnesium alloy wheels are very difficult to repair once they get bent or fractured due to high-speed impact on the road while driving. Once damaged, you will most likely have to purchase a new set of wheels.
Aluminum Alloy Wheels: Features and Benefits
Aluminum alloy wheels are more commonly used than magnesium wheels.
They also come fitted with the car as OEM fittings only these days.
Some of the most salient benefits are provided below:
Aluminum alloy wheels are available in a wide variety of choices to meet your needs.
There are available in different finishes like the regular painted wheel, powder coated wheels, anodized wheels, chrome plated wheels, diamond cut wheels, etc.
Each of these finishes come with their own benefits and you can choose the one which meets your requirements.
They also come with the option of customizing them as per your needs.
These aluminum alloy wheels are available in different sizes in the market.
You must ensure that you buy the one which is correctly sized for your vehicle.
Aluminum alloy wheels are more durable compared to the magnesium alloy wheels and hence, as a result, will last longer.
Aluminum wheels can withstand the impact of high-speed impact better than the magnesium wheels.
Even if these wheels are slightly damaged, they can be easily repaired and refurbished while the magnesium wheels are very difficult and most of the times near impossible to repair.
They are also more resistant to generic wear and tear, corrosion, and rust when compared with magnesium alloy wheels.
Most cars these days come factory fitted with aluminum alloy wheels which makes them more suitable for street use than magnesium wheels.
Aluminum wheels are costly than the regular steel wheels.
The price of the wheels may depend on a number of factors like the brand, manufacturing process, size, styling, finishing, etc.
It is recommended to do proper background research before buying aluminum wheels as there are plenty of options in the market and each manufacturer charges differently.
The high initial cost is compensated by benefits like longer lifespan and savings of cost due to improved fuel efficiency as a result of using these aluminum alloy wheels on your car.
These wheels provide a marked improvement in the handling of your car when you make the transition from the traditional steel wheels.
Aluminum alloy wheels are lighter and increase the steering and handling efficiency of your car.
It also improves the functioning of the braking system which ensures that it is easier for you to accelerate and brake the car instantly.
They provide better heat dissipation than steel wheels which protects the functioning of the braking system and ensures that there are fewer braking related issues in your car.
The tires also do not wear and tear quickly and retain their shape and longevity.
Overall, using aluminum alloy wheels increases the handling of your car and makes it more responsive.
Aluminum alloy wheels need more maintenance than the steel wheels.
They should be cleaned and washed regularly to protect them from brake dust, debris, corrosion, and rust.
You should polish these wheels and also use wheel wax for better protection of the wheels.
They should be rebalanced every time they are removed from the car for cleaning, painting, or any other purpose.
Drawbacks of Aluminum Alloy Wheels
Aluminum alloy wheels have the following drawbacks:
- Aluminum alloy wheels are costlier than the steel wheels.
- Good alloy wheels can cost you up to thousands of dollars while you can get steel wheels at a fraction of the cost.
- Generally, aluminum alloy wheels are not as durable as the steel wheels.
- They can hardly withstand the impact which steel wheels can and are more vulnerable to bending and fractures due to high-speed impact.
- Another drawback of the alloy wheel is that they are difficult to repair.
- When they are heavily damaged, the chances of them getting repaired are very less and you may have to end up buying new wheels.
Production Methods for Alloy Wheels
Alloy wheels are manufactured by different processes which are detailed below:
Forging is a process wherein the wheels are forged under a strong forging system.
This is a complex manufacturing process which involves heating, rolling, applying high pressure, hammering of the alloy, etc.
When the alloy undergoes all these processes, it changes the molecular structure of the alloy and makes it stronger and more lightweight.
Most aftermarket alloy wheel manufacturers are now using forging for producing the best quality wheels.
Though wheels produced by forging process are more ductile and stronger, they are also costlier than wheels manufactured using other technology like casting.
Wheels manufactured by forging are multi-piece wheels consisting of 2 or 3 different pieces.
Every piece originally is an alloy billet which is given the shape of a wheel using the forging process in the case of one- piece wheels.
In case of multi-piece wheels, these alloy billets are transformed into wheel parts which are then assembled together to give the final shape of the wheel.
High-Pressure Die Casting (HPDC)
HDPC method uses a die arranged in a large machine that has a high closing force to clamp the die closed.
The molten alloy is then poured into a filler tube which is also known as a short sleeve.
The molten alloy is pushed into the die by using a piston which works with high speed and pressure.
Once the molten alloy is pushed into the piston, it solidifies and the resultant wheel is released when the die is opened.
Alloy wheels manufactured using this technology are more cost-effective than forged wheels.
However, they are less ductile and less durable than forged wheels too.
Low-Pressure Die Casting (LPDC)
LPDC method uses a steel die which is arranged over the crucible which is in turn filled with the molten alloy.
The crucible is sealed against the die and pressurized air is used for forcing the molten alloy into the die.
These wheels have better ductility but are still lesser in quality compared to forged wheels.
Gravity casting is one of the cheapest methods for making alloy wheels and has been in use since the 1920s.
The wheels manufactured using this technology have improved ductility and durable features.