American Racing wheel
Weld Magnum III RT Black Anodized Wheel

This American Racing wheel has a positive offset. Notice how the center hub mounting surface is locted all the way to the outside of the wheel. This style is common on most front-wheel drive vehicles.

Negative offset wheels, like this Weld Magnum III RT Black Anodized Wheel, are common on rear-wheel drive vehicles, including classic musclecars, street rods, etc. Notice the "deep dish" look created as the hub mounting surface is located inward and way from the outside of the vehicle.

Should you go with the powdercoated or chrome-plated wheels? How about a sporty five-spoke wheel…or maybe the classic smoothie look?

Yes, style and finish are important considerations when choosing a new set of rims, but bolt pattern, backspacing, and offset are absolutely crucial. Outside of the physical size of the wheel, these are the three most-common measurements used to match the right wheel size to a particular vehicle. We’ll cover the basics of wheel offsets now–look for a post on bolt pattern and backspacing in a later post.

Offset vs. Backspacing

Offset and backspacing are similar measurements. While backspacing is the distance between the back of the rim flange and the hub mounting surface, offset is the distance between the centerline of the wheel and the hub mounting surface. Measured in millimeters, offset is the measurement of choice for many custom wheel manufacturers.

Positive vs. Negative Offset

A wheel can come with a zero offset, positive offset, or negative offset. Zero offset occurs when the hub mounting surface is even with the centerline of wheel. Most factory rims come with a positive offset, which is achieved when wheel manufacturers place the hub mounting surface to the street side of the centerline. Most front-wheel drive vehicles use positive offset (or dished-out) wheels; most rear-wheel drive vehicles have negative offset wheels. Negative offset wheels locate the hub mounting surface to the brake side of the centerline, giving them a “deep dish” appearance.

Choosing the Right Offset

If the wheel offset is not correct for your vehicle, handling can be adversely affected. For example, excessive negative offset can cause steering wheel kick-back and place additional stress on your vehicle’s entire suspension. Talk to your sales rep or wheel manufacturer to help you determine a range of acceptable offset ratings for your vehicle. When you receive your new wheels, test fit them on your car or truck before mounting the tires. Once the tires are mounted, the wheels can’t be returned.

Author: David Fuller

David Fuller is OnAllCylinders' managing editor. During his 20-year career in the auto industry, he has covered a variety of races, shows, and industry events and has authored articles for multiple magazines. He has also partnered with mainstream and trade publications on a wide range of editorial projects. In 2012, he helped establish OnAllCylinders, where he enjoys covering all facets of hot rodding and racing.