Types of Aftermarket Wheels

There are several types of construction that are used to make wheels for the aftermarket. The type of construction does not necessarily mean that one type is better than the other. Some types of construction allow for more elaborate styling or finishing, others reduce weight, while others are for the purpose of duplicating the original equipment wheels. In any case, the strength and safety aspects of the wheel are based on the design and manufacturing quality built in by the manufacturer. Remember, as discussed in TECH Stuff #3, all the wheels sold should be tested to a recognized specification or standard by the manufacturer to assure that they are safe and reliable regardless of what type construction they are.

The following are the most common types of wheels offered by the aftermarket wheel industry.

Steel Wheels – This is where the aftermarket wheel industry got started. They consist of a steel outer/rim and a steel center. Chrome plating is very easy on this type because the rim and center are polished and chrome plated separately then pressed together and welded. Painting is also easy but is done after the wheel is assembled. Backspacing/offsets can be varied when the rim and center are pressed together. Trim rings and hub caps finish off these wheels nicely. Wire spoke wheels would fall in to this category but require much more maintenance in cleaning and runout (balancing).
Steel/Composite – This method of building wheels was started back in the 60's. It consists of a steel rim and a cast aluminum center. This allows for more styling in the center. The aluminum centers are cast with steel cleats or inserts on the outer edges so it can be pressed into the steel rim and welded just like the Steel Wheels. These wheels are offered primarily chrome plated.
1 Piece Cast Aluminum – This is now the most common wheel sold in the aftermarket. It offers the most variety of styling, sizes and finishes. These wheels can be painted, machined, polished or chrome plated. They are offered in sizes from 13" to 26" (28" & 30" are in development). These also offer a reasonable weight savings over Steel or Steel/Composite. The disadvantage of the 1 Piece Cast is the backspace/offsets are fixed in the mold.
Forged – This is the type that offers the lightest weight. Because of the forging process, the wheel can be built using much less material than a 1 Piece Cast. The styling is limited in comparison to a 1 Piece Cast and the tooling and manufacturing costs are much greater. These too can be painted, machined, polished or chrome plated. Because of costs the sizes offered are limited.
2 Piece Aluminum – Also known as Billet, this type of wheel has been around for about 20 years. Like the Steel Wheel, it is made of a rim and center. The rims are rolled or spun and the centers are cast, forged or machined billet aluminum. The rim and center are pressed and welded together which also allows for a variation in backspace/offset. Forged and billet aluminum centers are typically stronger than cast centers because of the density of the aluminum. Finishing is limited to painting, machining or polishing. Chrome plating is difficult because the welding has problems created by the copper, nickel and chrome from the plating process.
3 Piece Aluminum – These are also known as a Modular wheel. The rim is made up of 2 pieces, the front rim section and the rear section which are either spun or formed. The center can be of a cast, forged or machined billet type. The 3 pieces are assembled with the center sandwiched between the front and rear rim sections with bolts or rivets securing the pieces together. Styling is again limited, but finishing choices are like the 1 Piece Cast.

There are a few folks out there in the industry that will say wheels made by forging or from machined aluminum billet are stronger than cast wheels. That would be true if both wheels were made to the exact same design and dimensions. However, the strength or load carrying capacity and durability of a wheel comes from the design and manufacturing quality, based on the type of construction. The biggest advantage gained from forging or billet is weight. Because they are stronger, less material is needed. Regardless if it is steel, cast aluminum, forged or machined from billet, the wheel should still meet performance testing standards to be deemed safe and reliable.