MAY 20, 2019

What’s the Difference Between Wheel Types?

From an appearance viewpoint, your ride’s wheels can have a serious impact on it’s overall “coolness factor.” Today, the auto aftermarket provides an incredible selection of amazing wheel types in every conceivable size, design, and price range.

But appearance is only half the game. Unless your vehicle is a “beauty queen” that only goes to shows and appears in parades, your wheels should contribute to the performance of the ride.

So how can wheels help you go faster, carve up corners better, take on the roughest trails, and burn less gas?

The design has something to do with it but at the heart of the matter, you want a wheel that is strong and lightweight. The different processes used to make wheel types strong and lightweight are what drive the differences in prices. As it turns out, rearranging a wheel’s molecules to make it stronger and lighter is a fairly time-consuming task requiring some awesome equipment and an understanding of metallurgy.

Here’s a quick rundown on the difference between wheel types, how they are manufactured, and their pros and cons:

Pro Comp Series 51 Steel Wheels  (Auto Anything)

Steel Wheel Types

Up until a couple of decades ago, steel wheels were the most common wheels available. Making these things is a comparatively simple process. They are stamped out. Think a tool and die operation writ large. Stamping doesn’t leave a lot of room for decorative features and is typically limited to a hub cap with a logo. Steel wheels are strong and cheap to make but they are also heavy. Utilitarian is the best word to describe their value.

Aluminum Alloy Wheels (DTRBS)

Cast Aluminum Alloy Wheel Types

This is where we get into some cool looking wheels. Molten aluminum (with a sprinkle of other metals) is either poured (gravity casting) or sucked into (low-pressure casting) a mold. The casting is allowed to cool and solidify then the mold is removed. The rough casting is then trimmed and polished and voila…your wheel is ready. Obviously, the artistic effort here goes into the design of the mold.

The aluminum alloy wheel is significantly lighter than steel meaning there is less rotational mass making for more stable handling characteristics. But the casting process can come with durability and strength issues. There can be trapped air pockets that can result is pitting, oxidation, and even cracking. To compensate for the potential structural problems, cast wheels are over-manufactured meaning they use more metal than what would normally be required. Cast wheels are among the most affordable of the aftermarket offerings and are ideal for drivers who are interested in appearance over performance.

Cadillac Escalade with Lexani Forged LF-771 Wheels (Ekko Media)

Forged Wheel Types

These are the showboats of wheels. That’s another way of saying they are at the top of the financial food chain. Forged aluminum involves applying extreme pressure (8 to 10 million pounds psi) to the molten aluminum alloy forcing it into the desired shape. The combination of heat and extreme pressure striates the molecules in the metal making it denser and significantly stronger than cast metal. Because forged metal is stronger than cast, less metal is needed to produce the same size product (think thinner). Less metal equals less weight.

Forged metal can be buffed to a jewel-like finish. In the event you scratch a forged wheel, you can buff the scratch out. With the softer cast wheel, that scratch is there forever. You can also cut (using CNC) sharper features in the face of the wheel allowing for some amazing designs. These wheels are what you find on SEMA show cars.

Ford S550 Mustang GT on TSW Geneva Rotary Forged Wheels(TSW Wheels)

Rotary Forged

Many manufacturers are jumping on the rotary forged process as a compromise between casting and forged methods. Rotary forged (also known as Flow or Flow Stream) is basically a cast wheel that is then heat-treated under pressure to create a lighter, stronger wheel than straight casting.

The molten alloy is poured or injected into a mold but not allowed to fully cool. While it is still hot, the barrel of the wheel is mounted on a machine that will spin the wheel. As it is spinning, a flame is applied to keep the heat up and two or more special devices applying pressure to the spinning barrel. Think potter’s wheel. You make a bowl by spinning a chunk of clay and applying pressure with your fingers to thin out the walls. The same thing is happening to the barrel of the cast wheel.

Because heat and pressure have been applied, the barrel has been forged meaning its molecules have been striated and the metal is much stronger. The face of the wheel remains the same as a cast wheel. The net result is a lighter, stronger wheel that cost the same or a little more as a cast wheel.

Lamborghini Huracan Performante with HRE S201(Tag Motorsports)

2 and 3 Piece Wheel Types

These are the Rolls Royce of wheels. They offer the greatest opportunity for customization. Essentially, they have forged wheels with multiple components. A two-piece forged wheel consists of a rim and an inset, complete with spokes. A three-piece uses the same concept except for the rim consists of two separate halves. Using two halves allows manufacturers an almost limitless selection of widths. These wheels are for high rollers. It’s not uncommon to see them priced at $1500 to $3000 a copy. However, for that price, you will own bragging rights for the coolest wheels on the block.