Wheels are usually what most people notice first on a customized vehicle. For car folks, they’re automotive jewelry, and no other modification has as much visual impact as a new set of rims. This form of automotive personalization is the quickest and least expensive way to proclaim, “This ride is mine.”
When enhancing a rendering for a new concept, auto designers even use the expression “cheat the wheels” – making them fill the well as much as possible, even to the point of impracticality.
But there are other reasons to upgrade your rolling stock besides just for appearance’s sake. Going from a stock steel wheel to an alloy rim can improve both handling and braking by reducing unsprung weight (the amount of mass at each corner of your vehicle) and you can also go to a wider rim for more tire grip.
But this time-honored technique isn’t all that simple. Just ask veteran vehicle customizer Larry Weiner of Performance West Group who has decades of experience with fitting aftermarket rims. Over all his years of building hundreds of show vehicles, he’s encountered just about every possible problem along the way. He cites all sorts of issues that you might encounter – everything from rubbing the fenders to clearing the calipers, and weak construction to overloaded bearings.
Considering Rim Offset
Offset is defined as the distance from the backside of the wheel mounting pad to the outside of the rim flange. “Offset is a critical component,” Weiner points out. “It locates the rim in the wheel well, and if it’s not correct, it’ll push to the outside of the car.” Some customizers, such as those who build lowriders or off-road rigs, actually prefer this “outboard” type of mounting, but note that the resulting side-loading on the bearings can be unsafe and even illegal in some states.
Even so, one of the newer trends in the market is “hellaflush” where the wheel nearly touches the fender lip and also has an extreme camber angle (tilting inward at the top). Before committing to a certain size, make sure your wheel shop pro knows how close you can get without scraping. As Weiner advises, “It’s better to err on the conservative side than getting stuck with a set of expensive rims that won’t work on your vehicle.”
Because the wheel-well dimensions might differ somewhat from side to side due to staggered mounting of the shocks or other factors, be sure to measure both sides of the car before buying different sizes of rim and tires.
Considering Rim Diameter
Diameter is another key factor to consider, not only when going larger, but also when fitting bigger brakes on older wheels. Most muscle cars in the 1960s used either 14- or 15-inch rims, but modern disc brakes might be too big to clear the rims. If the rim has spokes they will need to clear the calipers as well, usually by at least 1/8th of an inch.
As for going larger in diameter, if you step up to 17s, 18s or more, you’ll need tires too. Changing diameter will affect the calibrations on the speedometer, odometer and Automatic Brake System (ABS).
Some customizers prefer “staggered fitments” with bigger rear rims than up front. The margin of difference between the front and rear has to be fairly slim, otherwise it confuses the ABS, causing brake wear and handling issues. However on many wheels, you can run rear tires that are wider than the front while maintaining the same diameter front and rear so there are no issues with the speedometer, cruise control or ABS.
Obviously a larger diameter can also create clearance issues, so a suspension lift might be required on a truck (or that odd style of car with wagon wheels called a “donk”). Large wheels can add considerable weight, even if they are made of a lighter alloy than the stock rims. If that’s the case, you might need to upgrade the brake system as well.
Tires and Lug Nuts
Speaking of tires, yet another measurement to keep in mind is the rim width. Is it compatible with the recommendation of the tire manufacturer based on size? The aspect ratio, the relationship between a tire’s height and width, is very important and can be a safety issue. When you shop for tires, make sure they are compatible with the wheels, especially on trucks, where having the correct load rating is important as well.
Lug nuts are a critical detail to remember. Will the factory fasteners fit your custom wheels? If not, factor a new set into the cost, and check if you’ll need a special adaptor tool to fit them. Note, too, that stud sizes on newer vehicles are larger, so older lug nuts might not fit. Also, to protect your investment in premium wheels, locking lug nuts are a wise choice (though not a guarantee of protection from a persistent wheel thief).
How about converting a four-lug hub so it can accept a five-lug wheel, or even an eight- to a ten-lug wheel on a large pickup? You’ll need to either switch out the front hubs and axle or use billet adaptors. If you go the latter route, use a single-piece unit, the thinnest possible (about an inch) so the wheels don’t stick out too far.
Time to Purchase
As noted earlier, appearance is an essential part of going to custom wheels, so don’t forget the maintenance aspect. “Billet is a lot of work to maintain,” Weiner points out. “Once oxidized, it looks lousy and need polishing. So if you want billet rims, go with a clear coat for zero maintenance.” Also, he says to be aware that while chrome-plated cast wheels are relatively inexpensive and look great when new, in damp climates the surface tends to get pitted, losing its luster.
Forged wheels are stronger than cast ones, so if you can afford them, they’re a better choice. That’s because lower-profile tires with less sidewall height are typically used on bigger rims, and there’s less cushion when you hit a bump or pothole, so make sure you buy high-quality construction.
By keeping these basics in mind, you’ll be rolling down the road in style and safety and getting a thumbs-up too.
|Aftermarket Wheel Examples|
|ET Classic Five Wheel|
with Mickey Thompson Tires
|Hurst Wheel and Tire Package|
|Oasis Wheel on a Pontiac GTO|
|Voxx BG Gasser Wheel on a Chrysler 300|