Bolt patterns are fairly simple concepts. Your first number in the bolt pattern will always be the number of studs on the vehicle. for example, the first image in the picture above is a 4 lug. Your second number, will be the spread as measured above. This number can me either metric or standard. For the first image, if the spread or distance between the two were 100mm, then our bolt pattern on that vehicle would be stated as 4x100. The same process carries to all vehicles.

The easiest way to measure backspace is to lay the wheel face down onto the ground so the backside of the wheel is facing up. Take a straight edge and lay it diagonally across the inboard flange of the wheel. Take a tape measure and measure the distance from where the straight edge contacts the inboard flange to the hub mounting pad of the wheel. This measurement is backspace. The above photo shows three wheels with 2",3", & 4" backspace.

To calculate offset you'll need the following measurements:
::: Wheel backspace
::: Wheel Width
::: Wheel Center line (wheel width / 2)

Subtract: Wheel center line from Wheel backspace to get offset. If backspace is less than the wheel centerline the offset is negative If backspace is greater than the wheel centerline the offset is positive.

Tip:
::: To convert from inches to mm multiply by 25.4
::: To convert from mm to inches divide by 25.4
(or use the chart below)

IMPORTANT NOTICE: As with all types of wheels retorque lug nuts after the first 25 miles & at 100 mile intervals until lug torque is maintained.

Note: Always refer to Owner's Manual for proper factory specifications which will take precedence over the listed recommendations here..

Bolt pattern (also referred to as lug pattern or bolt circle) is determined by the number of bolt holes and the bolt circle diameter.

Hub Diameter (also referred to as center bore) is the hole at the center of the wheel.

Back spacing (also referred to as rear spacing) is the distance from the backside of the wheel mounting pad to the outside of the rim flange.

Offset: The distance from the centerline of the wheel to the mounting surface of the wheel.

Negative offset: When the back of the bolt pad is closer to the inside of the wheel; when mounting surface is inboard of the rim centerline.

Positive offset: When the back of the bolt pad is closer to the street side of the wheel; when the mounting surface is outboard of the rim centerline.

Your tires can tell you a lot about the issues with your vehicle. The most common patterns of wear are illustrated above. Be sure to check the air pressure in your tires once per month during normal maintenance, and you can avoid a costly mistake that could have been easily fixed.