• Choosing Custom Wheels is About More Than Good Looks

    Putting custom wheels on your vehicle can spice up your ride to bring back some of that new-car excitement. New wheels can also improve driving performance.

    But choosing tires and wheels for today’s automobiles is a lot more complex than it used to be, given all the smart technology built into modern vehicles and the huge variety of tire types now available.

    Before you buy, it’s good to know about the tradeoffs that come with changing your wheel and tire size. Your choices may affect handling. In some vehicles there could be a sacrifice in all-season traction, in others it may enhance it. You’ll likely get more responsiveness, with your ride more sensitive to road conditions than what you felt with OE (original equipment wheel and tire package). Your tire tread life could be improved or shortened.

    It’s also good to have a basic understanding of fitment, meaning what wheel-tire sizes can be properly mounted on your vehicle. Without knowing, you risk a setup that could affect vehicle clearance, cause vibration issues and alter your ride quality. The wrong package can cause contact with fenders, inner fenders, struts, shocks, tie rods, brake calipers and other suspension parts.

    Here’s what to know about choosing wheel-tire packages that will meet your driving goals and correctly fit your vehicle.

    First, Some Terminology: Are Wheels and Rims the Same?

    People often refer to wheels and rims as the same thing. The rim is actually part of the full wheel. It’s the outermost part of the wheel. It supports the tire and creates an airtight seal.

    The wheel refers to the whole shebang. It’s a metal disc with spokes and a specific bolt pattern (the pattern of holes) where fasteners called lug nuts or lug bolts attach the wheel to the vehicle’s hub.

    Parts of a wheel

    The rim and wheel can either be manufactured as one unit or a multi-piece assembly. For this article, we’ll assume the wheel and rim are one unit, and call it the wheel.

    Know Your Fitment to Choose Custom Wheels

    Any vehicle will have a range of wheel/tire diameter sizes of several inches that will fit properly. This gives you some flexibility when you want to tailor wheel size for looks and performance.

    Wheels are measured in inches, by diameter and rim width. The wheel diameter is how wide the wheel is across the center in inches. Rim width is the measurement from bead seat to bead seat (how wide the wheel is looking at it head on). For example, here’s a graphic showing sizing for a 17" x 8.5" wheel:

    Rim width and wheel diameter graphic

    To find wheel and tire packages that will work for your vehicle, start by collecting wheel diameter, tire width and tire aspect ratio.

    1. Find your wheel diameter.

    This is the distance between the two bead seats, the flat spots where the edges of the tire get hugged securely onto the wheel. This measurement will be stamped on the wheel, item E in the graphic below.

    2. Find the width of your existing tires.

    Tire width is the measurement in millimeters (mm) from side to side looking at the tire head on. It’s marked on the tire sidewall, item B in the graphic below.

    What tire sidewall numbers and codes mean

    You’ll note that this measurement is often offered in millimeters. If so, use this Tire Size Calculator to convert it to inches.

    3. Find your tire’s aspect ratio.

    This number is branded on your tire sidewall, item C in the graphic. The aspect ratio is a percentage. It’s the sidewall height divided by tire width. More specifically, it’s the height of the sidewall measured from wheel rim to top of the tread, expressed as a percentage of tire width. Our example tire has an aspect ratio of 65.

    A change in the aspect ratio usually means the tire sidewall height changes. This will result in driving performance differences.

    Wheel Size and Driving Goals

    With these three measurements, you have a baseline of what tire-wheel package sizing works on your vehicle. Now consider your driving goals and style preferences.

    “I’m just after chill looks.”

    Say you just want to personalize a vehicle to make it your own. If you’re all about the aesthetics but don’t want to change your current ride performance, it’s easy: You can keep the same sizing but swap out your wheels for something showier.

    “I want better acceleration and cornering.”

    If you love driving and are looking for performance enhancements, aftermarket wheels can play a role. Choosing a larger-diameter wheel will decrease the tire’s sidewall height. This adds responsiveness. You’ll notice higher stability and better cornering. You’ll achieve that low-profile style you’re after. Done correctly, larger wheels can improve acceleration and reduce braking distance. You’ll feel more road feedback.

    Bigger diameter wheels can also mean shorter tire life and higher price points than conventional sizes. You may feel bumps in the pavement a bit more. On full-sized pickup trucks, a larger tire and wheel package can mean you may not get as tight a turning radius as before.

    Another consideration for truck owners could be weight. The maximum plus size wheel-tire package for light trucks and SUVs may make the setup heavier than OE, depending on the type of wheel you pick. A heavier setup could mean longer stopping distances along with increased suspension and brake wear.

    “I want something sporty looking but I still want the smoothest ride.”

    Smaller wheels are mounted with tires that have a higher aspect ratio, resulting in a more comfortable ride with less road feedback. With taller sidewall tires, you’ll feel more flex when you turn corners, and you may notice a difference in handling. This sort of package manages impacts like potholes, speed bumps and debris better, protecting the wheels from damage.

    Getting into smaller wheels isn’t possible with every vehicle due to fitment. If you do have some room to go smaller, you’ll have lots of tire tread design possibilities.

    “I’m planning to run my wheel-tire package year-round.”

    Some wheel finishes require more maintenance in climates where winter deicing chemicals on the road are a factor. Be sure to ask about care before you buy.

    Wheel Plus Sizing Explained

    When you’re shopping for wheels you’ll come across some standard sizing terms. OE (original equipment) is the base wheel size. It’s what came standard on the vehicle from the factory.

    Wheel plus sizing graphic

    Plus sizing is when you boost wheel diameter. Minus sizing means you’re getting into a smaller wheel. Plus 1 sizing is increasing wheel diameter by an inch. Minus 2 sizing is downsizing wheels by two inches.

    You can also keep the wheel diameter the same but mount a lower-profile tire (the tread gets wider, the aspect ratio changes, but the height of the sidewall remains the same). This is called Plus 0 sizing.

    Here’s a comparison of how two wheel-tire packages of different sizes look on the same vehicle.

    18-inch wheels on a Ford Edge
    Car with 18-inch wheels. Note the higher tire sidewall.

    20-inch wheels on a Ford Edge
    Car with 20-inch, plus-sized wheel and low-profile tire. Note the shorter tire sidewall.

    Don’t Overlook Wheel Offset and Backspacing

    Offset and backspacing are two more considerations likely to come up during your search for the perfect wheel-tire package. They’re critical for proper fit.

    Without getting into lots of detail, offset and backspacing make sure there’s enough room for the new package to sit properly in your wheel well, so nothing interferes with your braking components and suspension, there’s no rubbing against bodywork and your car doesn’t become unstable around corners or when braking.

    One More Wheel Sizing Issue: Bolt Patterns

    Don’t buy those wheels yet. You need to verify that the bolt pattern will work.

    The bolt pattern is how many lug holes are on the wheels you’re buying and how far apart they are. It has to be compatible with your vehicle, so the lugs mate up with the studs on your suspension.

    Hub assembly with bolt pattern

    You can look for bolt patterns in wheel descriptions, but just because your vehicle may have five lugs it doesn’t mean that all five-lug wheels will fit. There are multiple bolt pattern possibilities on today’s vehicles, generally with four to eight lugs. And there are different ways of measuring between lugs, depending on the number.

    Even if the wheels you like have the right bolt pattern there's a possibility they might not fit, so get answers on this before you buy.

    Test Fit New Wheels Before You Buy

    The easy way to find out what wheel sizes, bolt patterns and styles are right for your driving and vehicle is to talk to a pro and try wheels on before you buy.

    A good tire store will consider your preferences then factor in all the issues:

    • Proper clearance, so wheels or tires don’t rub against bodywork, brakes or parts of the suspension
    • Compatibility with tire pressure monitoring
    • Proper traction control and stability
    • Maintaining accurate speedometer and odometer readings
    • Keeping tires within speed and load capacities

    Once this is nailed down, you can pick some options you find attractive and try them on for size virtually. Some tire retailers have computer tools that show how a wheel-tire package will look on your specific make, model and color vehicle. You can look at different spoke styles, lift or lower the vehicle and see what plus and minus wheel size options look like.

    Les Schwab Virtual Wheels kiosk

    When you’ve narrowed down your choices, tire stores with large inventories and knowledgeable staff can then put your vehicle on a lift and show you how the wheel and tire assembly you like really looks, to be sure it’s what you want. It often helps to see two combinations of wheels mounted at the same time for comparison.

    When you decide which you’re happy with, you can be on your way with a new wheel and tire package that day.

    Top 3 Custom Wheel Buying Tips

    Choosing an aftermarket wheel-tire setup is about more than just picking a style you like. Issues like proper clearance for brake system components, potential rubbing on body parts like fenders and mud flaps, offset spacing and bolt patterns can be overlooked.

    Your driving goals are just as important. Do you want enhanced handling? Are you willing to sacrifice some driving qualities for others?

    Remember these three tips as you’re shopping around.

    1. For most SUVs, CUVs and cars the overall diameter of the aftermarket package (wheel and tire combined) should be within 3 to 8 percent of the overall diameter of your OE setup.

    2. Bumping up to a larger wheel for a low-profile look? A plus-sizing rule of thumb is to increase tire width by 10 mm and decrease sidewall height by 5 to 10 percent for each one-inch increase in wheel diameter.

    3. Buying new wheels should be fun. The easiest way to make sure you get what you bargained for is to talk with a good tire dealer.

    Learn more about how to shop for custom wheels in our Learning Center posts on wheel finishes, aluminum versus steel, and more.

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