Measuring Backspacing When Buying Custom Wheels

There are few things that can make an automotive enthusiast happier than ordering a new set of wheels, and usually ordering is hassle-free. Most people think that as long as the bolt pattern matches, they can install a new set of wheels easily. However, bolt pattern is only part of the picture; you’ll need to consider offset and backspacing to ensure proper fitment. Here, you will learn how to select wheels with the right backspacing and offset for the tyres you’d like to use on your 4WD.

Backspacing and Offset Defined

Before you can choose custom wheels based on backspacing and offset, you need to learn what the terms mean. Backspacing is a measurement of the distance from the rim’s inner surface to the outermost edge of the rim’s inboard side. Offset is a measurement of the distance from the rim’s center to its outer edges. A wheel with a positive offset has a center situated toward the vehicle, while a wheel with a negative offset has a center set away from the 4WD.

Most factory-installed wheels have a positive offset. When you install larger tyres, backspacing should change to keep the tyres from hitting brake calipers and other parts. In choosing aftermarket wheels, most users choose those with a negative offset, which leaves room for larger tyres. Using car wheels with a negative offset will also make your vehicle slightly wider, which improves stability.

Fitting Custom 4WD Wheels

If your off-road vehicle is still equipped with stock axles, there’s a high likelihood that you can ask the wheel maker which set will fit your setup. However, if you want to measure backspacing yourself, it’s simple. Just run a ruler along both beads, and use a measuring tape to gauge the distance from the mounting pad to the ruler. Offset is simpler to calculate; measure the width of the 4wd wheels you deciding to buy, subtract the backspacing measurement, and divide that number by two.

Wheel Spacers

A set of wheel spacers is a cheap, easy way to add the necessary clearance between brake and steering components and your wheel/tyre combo. Using wheel spacers will give the same effect as running wheels with negative offset; they leave more room for large tyres. However, the use of wheel spacers can put more stress on spindles, wheel bearings and the axle housing. When buying wheel spacers, carefully measure your setup so you don’t buy a set that’s too big.