Alloy wheels can add a distinctive look to a car, improve handling, shorten braking distance and increase acceleration. But to achieve these goals one has to look beyond design and compare technical specs, production methods and performance characteristics of the wheels. The wrong set of wheels may cause a lot of disappointment and bring the exact opposite desired effects. But before you decide let’s talk about how alloy wheels are made.
Choice of base metals for alloy wheels
Most aftermarket wheels produced today are made of aluminum alloy; higher end wheels can also be made of magnesium alloy. The latter are more expensive but offer a number of sound benefits, due to their lighter weight combined with higher tensile strength and ductility (to learn more about properties of magnesium wheels, please refer to this article on our blog).
Casting, forging, flow-forming alloy wheels
A major factor that influences performance is the wheel production method. Alloy wheels can be cast, flow-formed or forged. Casting means that metal is melted and then poured into a desired shape. This is a very cost-effective technology, but unfortunately far from perfect. During the process of pouring liquefied alloy, its structure changes which results in uneven grain alignment and possible cavities. The forging process eliminates these problems completely, because the cold metal blank is pushed into shape by powerful hydraulic presses. Not only does this lead to finer grain alignment, it also guarantees lighter weight (around 30% weight reduction compared to casting) and higher strength. Forged wheels are the preferred choice of premium auto manufacturers and owners–and the only choice for the world’s most prestigious races, such as Formula One. High-quality true forged wheels require extremely powerful presses, and only a few factories in the world, including SMW, have the capacity to produce them. The flow-forming method is a combination of forging and casting. Flow-formed wheels fall between true forged and cast wheels in terms of characteristics. f1wheels.com offers more detailed information on wheel production methods.
Coating has less impact on automotive performance but influences the look and can significantly improve the durability of alloy wheels, especially important for magnesium alloys. At SMW we use special patented coating technology that significantly improves corrosion resistance (to the point that we can offer magnesium alloy wheels with a 10-year warranty against rust). Drivers must also decide between matte or gloss finish, but this is a matter of taste. There is also the option of diamond-milling that adds a more expensive and luxurious look to the wheels. During the process of diamond-milling, the wheels are machined with diamond tools to achieve extra precise clean lines.
In terms of performance, removing 1 kg of wheel weight equals removing 5 kg of the weight of the car. If shorter braking and acceleration are the primary goals, then forged magnesium wheels are the most suitable option (they are more than 50% lighter compared to cast aluminum alloy wheels). A production “trick” that can make any wheels even lighter are pockets–free spaces inside the spokes.
Larger and wider wheels used with low-profile tires provide better grip on the road, thus improving a vehicle’s maneuverability and leading to better cornering and turning. However, larger wheels are heavier, which may have a slightly negative effect on acceleration and braking. Staggered rims (wider wheels on the back or, in some cases, on the front) are often used as a compromise to achieve the best performance.
A wheel typically consists of spokes, rim, outer lip and inner lip. Widening the outer lip is often used to achieve a more dramatic, sporty look.
Although most wheels have a solid color, or a combination of 2 colors, in theory all of the wheel components can be made in different colors or offer different color accents. SMW designers often handle requests where a client wants, for example, a black wheel with a white outer lip and a red stripe on the spokes, or similar customized options. In cases like this, we start with generating 3D models to confirm that the final product will match the desired look, or modify it if necessary.
Whether you need a standard wheel design or have a custom request, our customer service reps can give you free consultation and help select the set of wheels with the most suitable specifications. Please email any inquiries to firstname.lastname@example.org