Basic automobile wheels are made from steel. Upgraded wheels, at an upgraded price, are referred to as alloy wheels. But what are alloy wheels and how are they different from steel wheels? Here are four FAQs about alloy wheels and their properties:
What Are Alloy Wheels Made From?
In metallurgy, an alloy is a combination of metals. For example, brass is an alloy containing copper and zinc. From the standpoint of a metallurgist, all automobile wheels are alloys. Steel is an alloy of iron, carbon, and other trace elements sometimes including nickel, chromium (a major component of stainless steel), manganese, and titanium.
However, the term “alloy wheels” typically refers only to non-ferrous alloys (alloys that do not contain iron), such as aluminum alloys and magnesium alloys. Although it is not a hard and fast rule, the term “alloy wheels” almost always refers to aluminum alloys, while the term “mag wheels” refers to magnesium alloys. To confuse matters even further, aluminum alloys may include magnesium along with trace amounts of nickel, manganese, titanium, and copper.
How Are Alloy Wheels Made?
Steel wheels are cheaper than alloy wheels and are less desirable than alloy wheels. One explanation for this is that steel wheels are formed by pressing sheets of steel into a mold then assembling and welding the pressed parts.
Alloy wheels, on the other hand, are either cast or forged. Cast alloy wheels are made by pouring molten aluminum alloy into a mold. Forged alloy wheels are made by heating, rolling, and hammering aluminum into the desired shape. Cast alloy wheels are easier to make than forged alloy wheels, but forged alloy wheels are generally stronger.
Because alloy wheels are cast rather than pressed, alloy wheels can have any design. As a result, alloy wheels are usually more stylish than steel wheels. Speaking anecdotally, most alloy wheel sales are made by tire shops primarily because of the appearance and the status that comes from alloy wheels.
What Are the Characteristics of Alloy Wheels?
The main difference between steel wheels and alloy wheels (aside from steel wheels being considerably less expensive), is that alloy wheels are much lighter while providing the same strength as steel wheels. Lighter weight wheels provide better handling and steering because the wheels will follow the road surface more closely. Additionally, lighter weight wheels mean greater fuel efficiency.
Aluminum alloys also dissipate heat better than steel which tends to heat up and remain hot. This means that alloy wheels dissipate heat from the brakes better than steel wheels, providing more stable braking.
What Happens When Alloy Wheels Are Damaged?
Aluminum alloys are ductile. This means that alloy wheels will usually bend or deform before cracking or breaking. This makes gives alloy wheels their durability, but it also means that alloy wheels can be bent or even cracked under severe stress.
Some auto repair shops are able to perform alloy wheel repair and painting. The extent and type of work needed to perform alloy wheel repair and painting depend on the exact nature of the damage. Although it is not always the case, most of the time it costs less to have an auto shop perform alloy wheel repair and painting rather than replacing the alloy wheel due to the expense of a new alloy wheel.
When an alloy wheel has merely been cosmetically damaged, such as curb rash, alloy wheel repair and painting is relatively simple. The alloy wheel is sanded, the damaged area is filled with filler, and the alloy wheel is painted.
When an alloy wheel has been cracked or bent, alloy wheel repair and painting is more involved. A cracked alloy wheel must be welded to repair the crack and painted. A bent alloy wheel must be heated to soften the aluminum alloy material, bent back into shape, and painted.
In either case, the alloy wheel should be examined by a car repair shop immediately, since a cracked or bent alloy wheel will severely impact the handling and safety of the vehicle. Even if the handling is not impacted, a cracked or bent alloy wheel can allow the tire to deflate. In fact, research by Indiana University revealed that about 1.4% of auto accidents were caused by under-inflated tires.
Alloy wheels look beautiful. Moreover, aluminum alloy is strong, light, and dissipates heat well, which improves an automobile’s handling, efficiency, and braking.