If there is only one feature you can do to your car that helps it stand out the most, it would be your car’s wheels. There are a lot to choose from, so looking for the right ones can be quite a daunting task. Things that you should consider as you choose your wheels are diameter, width, offset (or backspacing for you old hot rod guys), style, wheel mounting style, PCD (also known as bolt spacing), and construction. So, let’s talk about those items in a little more detail.
This is the first thing you’ll see and have to think about when you go to look for your next set of rims. While it may not seem like much, this can affect your car in many ways. You can change the acceleration and speed of your car. You can increase or decrease the un-sprung weight (this is the weight of the car that the suspension does not carry), which will also affect the rotational inertia of your wheel. It will also affect the tire availability and sizing choices, as many tires are beginning to be phased out with OEM wheels no longer being made in many cases under 16”. It will also affect what diameter brake rotor and what brake caliper you can use. The smaller the wheel, the smaller the brake package has to be in most cases.
When you go up sizes, it’s simply and usually known as “Plus Sizing.” A +1, for example, would be your OEM or current wheel size plus one inch. You can also “Minus Size,” as a few autocross and road racing cars do to take advantage of the added acceleration a smaller wheel and tire can bring (I’ll detail that in a moment). You have to be careful and factor in tire size as well. If you go too big, your wheel may rub the fender or fender wells as the tire gets larger and moves in turns, bumps, and normal suspension movement. You can compensate for that by decreasing the sidewall, but that brings its own challenges including a rougher ride. As mentioned earlier, you can affect the acceleration and speed your car will actually be capable of. A smaller wheel and tire diameter will give you more acceleration while a taller one will increase your speed. That’s also something to keep in mind if you got a speeding ticket after installing your new wheels and tires.
Width will affect the weight and tire width you can use on your car. Just as increasing the diameter, increasing the width will add more material which adds more weight and rotational mass. This means that you may need more braking power, however if your new wheel is made of lighter materials or a better construction, you don’t have to worry about it. A wider wheel also means a wider tire which can equal more grip, but again, it means more material. However, if you are stretching a tire, you will go with a narrower tire with a wider wheel. This can achieve a unique look and better fitment, but at the risk of a bead blowing out if you go for too much stretch or hit the wrong bump or pothole.
Offset and Backspacing are the same thing, but just different ways of getting to where your wheel will sit in relation to the hub on your car. Offset, specifically, is the measurement from the center of the wheel to the back of the wheel hub that sits with the brake rotor and is typically measured in metric. A positive (+) offset moves the wheel hub closer to the wheel face, a zero offset is dead center of the wheel, and a negative (-) offset is closer to the brake rotor. You’ll see offset used in describing wheels from countries outside of the United States. Backspacing, specifically, is the measurement from the back of the wheel to the back of the wheel hub and is typically measured in SAE inches. You’ll see backspacing mostly on wheels that are manufactured by companies in the United States. If you go too far, you can cause stress on your wheel bearings and could make them fail.
This is the most subjective part of the wheel, but there are more styles of wheel faces out there than I can count on 10 people’s hands and feet. You can find everything from solid wheels, multiple spokes, wire wheels, and anything in between. There can be some detriment in choosing certain styles of wheel faces, though, in terms of mass and from lack of openings for brake heat to escape. However, there are also certain wheel faces that benefit your aerodynamics, brake heat extraction, and even wheel mass.
Certain types of wheel faces will affect what type of brake package you can use, so be sure to make sure your caliper will clear the face of your wheel choice.
Wheel Mount Style
How the wheel mounts to the hub is critical. Many aftermarket wheels offer the ability to be mounted using a hub centric adapter. This will physically center the wheel by the center of the hub as you mount it to ensure you don’t get wheel wobble as you drive down the road because the wheel is off. Most of the time, this is done by installing a metal or plastic hub centric ring, but there are wheels designed for certain hub centers, too.
There are wheels that are known as lug centric, which means the lug nuts center the wheel rather than the hub. Normally, you can tell the difference by looking at the lug nut itself. Instead of a standard, 60 degree taper where it seats on the wheel, it has a shank with a washer and is known as a “Mag Seat” nut. You cannot use a Mag Seat lug nut on a wheel that is designed for a 60 degree seat and vice versa.
European cars, in most cases, use lug bolts instead of lug nuts and come in two different styles, a 60 degree seat and the ball seat. Just as with the Mag Seat, you cannot use a ball seat on a wheel designed for a 60 degree bolt and vice versa.
You also need to be careful with the Pitch Center Diameter, PCD or better known as Bolt Spacing. While two wheels may have 5 holes, one may be 5×114.3 and the other may be 5×100. However, going from metric to SAE inch can work in some cases. For example, Ford 4×4.5 bolt spacing will be the same as a Mazda 5×114.3. However, this isn’t always true. A 2012 Chevrolet Camaro and 2012 BMW 3-series both use a 5×120, but the Camaro is .65 mm larger in spacing between the bolts than a similar 3-series. The stud size on the Camaro is also a 14 mm diameter while the 3-series is only a 12 mm .
Finally, how the wheel is made is also important in choosing the right set of wheels. Cast wheels offer a much lower price point since the procedure of producing a cast is far less involved than the Forged wheel. However, a forged wheel will be stronger and lighter since it is made out of a single piece of metal. The act of forging actually compresses the metal molecules tighter, resulting in a stronger wheel that isn’t brittle like a heat treated metal would be. This also means that the material will be lighter than cast and far lighter than OEM wheels, while retaining the strength and integrity of the metal.
Wheel Construction is where the majority of the copycat wheels fail at reproducing. They try to reproduce a lightweight wheel by casting a similar shape as the original forged wheel, but not only is the process wrong, the casting material is not usually as a high quality material as better engineered castings. This can be dangerous as they try to even reproduce the weight of forged wheels with inferior casts. If you happen to be buying a wheel used always look for proper marks on the back of the wheel, the right decals, or casting marks on a forged wheel. If you see casting marks on a forged wheel, that will be the most obvious sign of a forgery and avoid it.
If you are buying a wheel new and have doubts, that should be your first sign that you don’t want to buy the wheel from that dealer and walk away. However, if that doesn’t stop you, look at the wheel and make sure to see manufacture logos on the wheel, both forged and cast. Even still, contact the manufacturer or the distributor and find out if the dealer is legitimate before you purchase any wheel. This is especially true on Ebay, Internet Sales, and Craigslist dealer ads since you may not be able to inspect the wheel prior to your purchase. They may end up being forgery wheels and not Forged Wheels.
As with any part of your car, always, always do your research before you commit to a purchase. Car parts are far more important considering that not only do they get us from point A to B, but they also have to do so safely and reliably. When it comes to your wheels, tires, brakes, and suspension components this factor doubles, if not triples. These parts stop, turn, and suspend your car and if you have a failure with any of these at any speed, the results are never good. Failure on these parts can lead to injury or death in worst cases.
Don’t take your wheels for granted as they don’t just have to support the weight of the vehicle, but also the loads the vehicle goes through as you drive. If you hit a bump or pothole wrong, it will bend a wheel almost no matter what the material is made of, but inferior cast wheels could crack or even break from normal impacts. Incorrect fitment can cause issues as well, from wheel bearing failure to tire failure from making contact with the suspension and body to even contact with the brakes. It’s just as important that your wheels fit as how they are made.
Finally, make a choice that you like, as premium wheels are going to be something you are going to enjoy for many years. If you get the wheel you like and spend the money on a quality piece; you will be happy the entire life of your wheels. In many cases, you’ll even transfer those wheels to your new car but check if they fit before you install.
-Justin Banner – Mackin Industries
For more on our contributor today, Mackin Industries and thier product line-up, visit their site online at http://www.mackin-ind.com/