Finding Your Wheels' Bolt Pattern

When it comes to finding the proper fitment for putting aftermarket or other new wheels on your car, the bolt pattern is possibly the most important consideration, even more so than offset. There is a perfectly obvious reason for this, since “bolt pattern” refers to the number of lug holes in the wheel and the distance between them. The bolt pattern on the wheel must match the bolt pattern on the car, or the wheel will not fit! Bolt patterns come in an extremely wide variety of sizes and can be expressed in either inch measurements or millimeters.

Most retailers, both brick-and-mortar and online, will know the proper bolt pattern for your car and present you with only wheels that can fit on the car. Online shops like Tire Rack, Discount Tire Direct, and 1010 Tires will do this automatically once you give them the year, make and model of your car, so most shoppers do not always need to have this information. However, there are still many situations where one might need to know what a bolt pattern is and how to find out what yours is.

Bolt Circle Diameter

The first concept one must be familiar with to understand bolt patterns is called BCD, for Bolt Circle Diameter. If you lay one of your wheels on the ground and draw a circle that passes through the center of each of the lug holes, that is the Bolt Circle, and it only remains to measure the diameter of said circle. This is perhaps easier said than done. Because BCD values can be within as little as half a millimeter of each other, (See below) measurements must be conducted with some care.

It's easiest to measure BCD with a bolt pattern gauge, something that is sold at many auto parts stores, however, few car owners find that they need a gauge unless they are measuring multiple different wheels. You can also measure BCD by taking the wheel off and using a tape to measure the lug studs on the car's rotor. If you don't know whether the BCD is in inches or millimeters, it's best to have a tape measure that has both scales on it. Run the tape from the center of one stud to the center of the stud that lies across the wheel from the first—with a 4 or 5-bolt wheel this means the second stud over, with a 6-bolt wheel it's the third stud over.

Once you know the BCD, the second step is simple—add the number of bolts. So if your BCD is 4.5 inches and you have 5 lug studs, the bolt pattern is 5 x 4.5”. If you have 4 bolts on a 100mm BCD, it's 4 x 100mm.

A cautionary note: The bolt patterns 5 x 4.5” and 5 x 115mm are actually within about half a millimeter of each other. (4.5” is 114.3mm) As such, it is possible to fit a 5 x 4.5” wheel on a 5 x 115mm car, but the fit will not be as correct as it might seem. Even that half a millimeter of difference means that the lug studs will not be centered in the wheel's lug holes, and when the lug nuts are torqued on, that lack of centering will bend the lug studs and cause the wheels to vibrate. If you have one of these two bolt patterns, take extra care—such as calling up a tire or wheel retailer or looking online—to ensure that you have the proper bolt pattern on both the wheels and the car!

Some Common Bolt Patterns for Various Autos