Everyone likes to ‘live large’ these days, and the same applies to the wheels and tyres on our cars and 4WDs. Not so long ago, 16″ or 17″ wheels and tyres were considered big; now, 20″ wheels are common. The advantages of plus-sized and deep dish wheels are up for debate, but some things are certain – before buying a larger-size wheel and tyre package, you’ll need to take a few steps first.
Consider the Backspacing
Wheel backspacing is one of the most important measurements to consider. Backspacing is the distance from the wheel’s lip down to its mounting pad, and it is important because it determines the positioning of the rim within the wheel well. A shorter distance between the lip and the mounting pad pushes the wheel outward; many front-wheel drive vehicles are set up like this. Larger backspacing moves wheels further into the wheel well; deep dish wheels in Sydney are a prime example. Most times, you’ll need different backspacing to fit larger wheels to your vehicle.
Make Calculations and Take Measurements
Because you want to fit your vehicle with a larger wheel and tyre combo, you’ll need to think about the package’s overall size. There are online sources that can help you properly size your wheel and tyre package; all you need to do is to enter your present and your desired wheel/tyre offset and size. You’ll get information on ride height, track width, outboard and inboard dimensions, and a lot more. Sizing calculators give a rough estimate, but they don’t consider clearances between tyres and brake lines, suspension parts and inner wheel wells.
Generally, you need at least ½” between the tyre and anything within the wheel well. If your new wheel and tyre package’s dimensions get into that space, you’ll need to choose a smaller wheel, a lower profile tyre, modify your vehicle, or choose a wheel with different backspacing. There are two ways to measure clearance:
- You’ll need a measuring tape and your current wheels and tyres. Measure from the tyre to parts of the inner wheel well, and to brake and suspension parts. Remember to take measurements on all four rims due to differences in body panel tolerances, and measure front wheels in both straight and fully locked positions. Clearances at full lock can be tight, especially with inner fender wells.\
- Another way to fit larger wheels is to use a wheel fitment tool. These tools simulate wheel diameter, bolt pattern, wheel width, tyre profile and backspacing on your vehicle. Bolt the fitment tool to the brake hub, adjust it to the dimension of your desired wheel and tyre package, and turn the tool to see if clearance is sufficient. Wheel fitment tools can typically simulate wheels from 15″ to 30″ in diameter.
Deep dish rims and low profile tyres can make your vehicle look stylish, but there are things to consider before fitting. By following the steps above, you can ensure that the wheels and tyres you choose will fit your car without any clearance issues.