Definitions and Terminology

Stock OEM Wheel Size (Diameter and Width)

The OEM Wheel Size is the Rim Diameter and Width which comes stock on the vehicle. In some cases your vehicle may come with many different size options. We list the most common size on this site.

Bolt Pattern

Bolt pattern or bolt circle is the diameter of an imaginary circle formed by the centers of the wheel lugs. Bolt patterns can be 4, 5, 6, 7, or 8-lug holes. A bolt circle of 4-100 would indicate a 4-lug pattern on a circle with a diameter of 100mm.

Thread Pitch

The thread pitch is the distance between threads expressed in millimeters (measured along the length of the fastener). For example a lug nut with a thread pitch of12mm x 1.5mm means that the stud diameter would be 12mm and the distance between one thread and the next is 1.5mm.

OEM Hex Size

OEM Hex size is the size of the head of the nut or bolt. This is important to make sure that your lug wrench will fit the lug nuts or lug bolts in case of a flat tire.

Centre Bore

The center bore of a wheel is the machined opening on the back of the wheel that centers the wheel properly on the hub of a vehicle. This hole is machined to exactly match the hub so the wheels are precisely positioned as the lug hardware is torqued down. Keeping the wheel precisely centered on the hub when it is mounted will minimize the chance of a vibration. Some wheels are vehicle model specific and will come from the factory with a bore machined to match that vehicle. Some wheels are designed to fit multiple vehicle models and will use a centering ring system to reduce the bore size to match the hubs of different vehicles. These rings keep the wheel precisely positioned as the lug hardware is torqued down.

Some wheels are non-hub centric by design. These are known as lug-centric wheels. With these wheels it is critical to torque the lug hardware with the vehicle on jack stands, off the ground. This allows the nuts or bolts to center the wheel and torque down without the weight of the vehicle pushing them off center.

OEM Offset

The offset of a wheel is the distance from its hub mounting surface to the centerline of the wheel. The offset can be one of three types (measured in millimeters).*

Positive Offset

The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.

Negative Offset

The hub mounting surface is toward the back or brake side of the wheels centerline. "Deep dish" wheels are typically a negative offset.

If the offset of the wheel is not correct for the vehicle, the handling can be adversely affected. When the width of the wheel changes, the offset also changes numerically. If the offset were to stay the same while you added width, the additional width would be split evenly between the inside and outside.

*Backspacing, similar to offset, is the distance from the hub mounting surface to the inside lip of the wheel (measured in inches).

Recommended Wheel Torque

Proper installation requires that the wheel lug torque be set to the recommended specification for your vehicle.

Unless specifically stated otherwise, wheel lug torque specifications are for clean and dry threads (no lubricant) that are free of dirt, grit, etc. Applying oil, grease or anti-seize lubricants to the threads will result in inaccurate torque values that over tighten the wheels.

A thread chaser or tap should be used to remove any burrs or obstructions of the threads allowing the lug hardware to be turned by hand until it meets the wheel's lug seat. Once lugs are snugged down, finish tightening them with an accurate torque wrench. Use the appropriate crisscross sequence (shown below) for the number of wheel lugs on your vehicle until all have reached their proper torque value. Be careful because if you over torque a wheel, you can strip a lug nut or hub, stretch or break a stud or bolt, and cause the wheel, brake rotor and/or brake drum to distort.

If you are changing from original equipment wheels to aftermarket wheels, the thickness of an alloy wheel can differ from Original Equipment wheels, and you must verify that the lug nuts or bolts will engage the threads. Refer to the chart below to determine the number of turns or the depth of engagement typical for your stud or bolt size.

Hardware Size Minimum Number of Turns of Hardware Engagement

12x1.50mm 6.5

12x1.25mm 8

14x1.50mm 7.5

14x1.25mm 9

7/16" 9

1/2" 8

9/16" 8

When installing new wheels you should re-torque the wheel lugs after driving the first 80 to 150 kilometers in case the clamping loads have changed following the initial installation. This is necessary due to the possibility of metal compression/elongation or thermal stresses affecting the wheels as they are breaking in, as well as to verify the accuracy of the original installation. When rechecking torque value, wait for the wheels to cool to ambient temperature (never torque a hot wheel). Loosen and retighten to value, in sequence. Simply repeat the same torque procedure listed above.

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