The need for knowledge of wheel bolt pattern and backspacing arises when you plan on customizing your vehicle with expensive aftermarket wheels. If you lack the knowledge about bolt pattern and backspacing, you will most likely end up buying wrong measurement wheels for your vehicles. You will either have to return the wheels or sell them away. To prevent the issues of buying a wrong custom rim for your vehicle, you will need to learn about bolt pattern and to backspace while also learning to measure them yourself.
Bolt pattern is described as the diameter of an imaginary circle that is formed by the wheel lugs that hold the studs. It is an evenly spaced area around the wheels which the bolts are attached to fix the tyres. The usual bolt patterns can be four, five, six, and eight lugs. If a bolt circle is 4×100, it means that the lug pattern is four bolts in a circle of 100mm. Measuring bolt patterns is important for every vehicle owner who is planning to get a new design, size, and finishes of the wheels for their car or truck. Purchasing a new set of wheels to add value to the looks of the vehicle and may also improve the performance. Buying a customer wheel without measuring bolt patters can make them completely useless. This guide will explain the process of measuring the bolt pattern.
Jack up your vehicle and place jack stands carefully under it. You will need to make sure of your safety through the entire process.
Next step is to remove the wheels with the lug-nut wrench. Some also use ratchet and socket for this job. Place the bolts somewhere safe where you will not lose them. Clean the rims with a dry piece of cloth for any dirt.
Next step, you will measure from the centre of one lug to the centre of the lug that is direct across from it. This will only work when you have four, six, or eight-lug hubs. Measure the distance using the metric side of a ruler. The measurement can also be done in inches, but millimetres provide the most accurate reading to find the perfect fit. Even a millimetre difference will make your custom rim completely useless. For example, if you have four lugs and the distance between the two lug centres is 100mm, then the bolt pattern will be 4×100. If you have a five-lug hub, you will need to measure the centre of one lug to the centre of the third lug. The bolt pattern will be 5x(the distance between the lugs). The last step is the put the wheel back on the car until you can purchase a new custom one to replace it.
Backspacing of a wheel is the distance between the mounting pad and the back of the rim flange. To measure backspacing, you will need to take the wheel off the car and lay it flat on the floor. The brake side should face up. Use a straightedge across the wheel and measure down the mounting pad. You may even have to deflate your tyre to get an accurate reading. This distance will be your backspacing.