Types and Finishes
Let’s talk about wheel construction, types of finishes and the pros and cons to each.
Understanding the nuances of each will allow you to guide your customer to the right kind of wheel to fit their specific needs.
First, wheel construction. Almost everyone is familiar with steel wheels – an inner face welded to an outer rim. But what about aluminum or alloy wheels? How do they differ and what’s their purpose?
One-piece cast wheels are just that. They are formed from molten metal injected into a segmented mold. Once cooled, it’s removed from the mold as a new wheel. From there it goes through the usual machining and cleaning processes.
Cast one-piece wheels are typically the heaviest of the three wheel types, although advances in mold design have significantly reduced their weight. A big plus to this wheel type is the strength of the outer flanges – where the tire beads meet the wheel.
Another plus is these wheels can withstand a great deal of punishment, making them a good choice for off-road applications. If they’re damaged, repairing them is usually possible. Also, the design is only limited to imagination and mold constraints, giving consumers lots of choice.
Another one-piece option is the forged wheel, which is milled out of a solid chunk of aluminum (or an alloy) to form the wheel. While they can painted, polished or chrome-plated, one-piece forged wheels are usually offered in only one offset per size, so you don’t have the flexibility to adjust the backside setting.
Two and Three Pieces
Two-piece wheels consist of a center that is welded to an outer rim. The centers can be cast like a one-piece wheel or machined out of solid aluminum or alloy (forged or billet).
The outer rim, however, is usually "spun" from flat metal and then welded at the joining seam. There are some instances where a cast outer rim is used, especially to create the "waterfall" or soft lip that doesn’t allow for weights to be hammered on the outside flange.
Centers on two-piece wheels are usually painted or polished, and the outer rims are usually polished. Rarely is a two-piece wheel chrome plated, except in the case of a composite wheel.
A composite wheel is created when an aluminum center is welded to an outer steel rim. The center is chrome plated separate from the outer rim, then pressed together and welded. Typically, a weight savings is realized with a two-piece wheel, because the outer rim is lighter than the comparable part of a one-piece wheel.
One major benefit to this type of wheel is the availability of various widths and backside settings. This wheel can be custom-built to exact measurements, allowing you to maximize the fender well space by choosing the widest wheel and biggest tire combination to fit the vehicle.
Three-piece wheels are designed so that the center, formed by one of the previously mentioned processes, is bolted to two sections of outer rim halves. This allows change to the width of the front and back halves of the wheel to create the desired backside setting.
Three-piece wheels are extremely expensive compared to the other two types, but they offer the biggest advantages and flexibility. With all of the advantages of two-piece wheels, three-piece units can be custom chrome-plated by having the center and outer rim half plated, then assembled with bolts.
Light weight combined with superb strength are the key features of a three-piece wheel. Porsche, BMW and other high-end sports cars all feature three-piece wheels, and there are several companies in the U.S. that produce or sell some of the finest aftermarket wheels in the world.
Next, let’s look at wheel finishes and the pros and cons to each. First, the painted wheels. These wheels have a powdercoat paint that is electrostatically applied. This means that they hang on a hook that draws a negative current through the wheel while positively charged paint is sprayed on the wheel.
Clearcoat is then applied over the paint to protect the paint. A baking process will cure the coating to a hard durable finish.
Pro: These wheels can be refinished if damaged and only require soap and water to clean. (Never clean a hot wheel or clean in direct sunlight. Some cleaners react to heat and can cause damage to the clearcoat.
Con: The finish doesn’t have the high luster shine like polished or chrome.
Next is the polished wheel. Here, the bare metal is color buffed using a polishing rouge, which is available in different grits. Once the wheel is cut with a heavy grit and sandpaper, it is buffed with a medium grit to smooth the surface. Advances in technology have created new processes that allow the wheel to be polished on a lathe with special diamond bits.
Pro: These wheels can be repaired if scraped or bent. They have a reflective finish that looks good and is a modest increase in price over painted wheels.
Con: This wheel will become dull over time and have to be polished to bring back the luster of the finish. Waxing will prolong this required maintenance.
Last is the chrome wheel. A common misconception is that these wheels are "dipped." Although new "chrome" paint processes have been introduced in the last few years, the most prevalent chrome plating process is the electroplate. Chrome plating is part science and part luck. Wheels are placed on a rack that has contacts to draw negative current through each wheel. After a few cleaning processes, the wheel is placed in a copper solution that is positively charged. This causes the particles of copper to form on the surface of the wheel.
Next, the wheel is removed from the copper and the finish is buffed to a high shine. Then it goes into a nickel plating process, which adds both a semi-bright and bright layer of nickel to the wheel.
In some cases a micropourus nickel is added to further enhance the durability of the finished plating. Finally, the wheel has the chrome applied to seal the nickel, otherwise the nickel would tarnish like a coin.
What you see isn’t so much chrome as it is nickel, but common nomenclature is to call it a chrome wheel.
Pro: Extremely reflective finish that them the most desirable of luxury wheels. They generate excitement, especially in a showroom, that attracts customers. Wash with soap and water and the finish will remain brand new.
Con: If the wheel is curbed or scratched, generally it can not be repaired. A heavy salt environment can lead to corrosion that will attack the finish. Wax is a good preventative measure for this.
Technology has given your customers a lot of wheel options. I hope that this will help you to guide your customer to the right wheel to fit their desires and budget.