One Piece Wheels vs. Multi Piece Wheels
Various Designs of Aluminum Alloy Rims What is the difference between a single, a 2-part, and a 3-part wheel? How can you tell if you have a multi-part wheel or a decorative imitation rim?
Compared to steel wheels, aluminum alloy wheels keep growing in popularity not just because they are lighter, but more so because of their cosmetic properties. They come in a wide variety of finishes and designs. The most common kind of aluminum wheel is a cast, single piece but 2-part, 3-part and multi-part imitation rims are also available as an aftermarket option.
Single piece wheels are usually supplied as original equipment with most cars. These are cast, forged or spun aluminum. Often the spokes are cut out with a milling machine.
Two-part rims are a different look than one-part rims. The barrel is one part, and the spoke section is the second part. The spoke section is bolted or screwed onto the barrel section. The screws or bolts add to the decorative look. Often, the bolts and/or screws are over-torqued so that they cannot be removed. If they are removed, replacement screws may no longer properly thread into place. This can be a hazard if a car is driven with a rim that has been taken apart. There are exceptions. If the barrel is bolted, new bolts and nuts are safe to use.
To the left: One part Land Rover wheel
Three-part rims are used for high-performance tires that are very wide. A three-part rim consists of two barrel parts and a spoke section. The two barrel parts and the spoke section are bolted together to form one piece. The seam between the two barrel parts is caulked with a special aluminum caulk, which adheres to the aluminum barrel parts. Like a two-part rim, the bolt heads are a decorative detail.
Left: Two-Piece VW Rim Right: Imitation Two-Piece Mercedes Rim
Imitation 2-part rims are becoming very popular. These after-market rims are really one-part rims made to look like 2-part rims. They have decorative bolt or screw heads, which may be made of metal, but are more often made from chrome-plated plastic. These decorative bolts are press-fitted and are difficult to replace. To quickly tell if your rim is really a one or a two part rim, just feel behind the spokes and you will not feel the seam if it is an imitation. The growing popularity of these rims is due to their resemblance to to 2-part rims and their lesser cost. Though imitation two-part rims may often be expensive as well. Regardless, they look good and can be very good quality.