Wheel offset is the distance between the centerline of the wheel and its hub surface. This is the number that’s calculated in mm or inches and lets the car owner know, how much of wheel will stick in or out from the wheel mounting surface. It’s important to consider the wheel offset not only from cosmetic point of view, but also in terms of safety and performance.
Selecting the proper wheel offset is always about finding the right balance between running as close to stock as possible, and enjoying custom look of aftermarket wheels.
Wheel offset: OEM vs aftermarket
No matter what’s the make and model of your vehicle, if you are running stock wheels, they most probably have high positive offset. The regular offset index is between 30 and 40 mm. This way, the wheels get under the vehicle body more, which allows keeping the gravity center close to cockpit. This makes the body narrower, and that’s the way the carmakers engineer the vehicles.
And there’s nothing much wrong about the +30mm offset, except of the fact, that the wheel hub gets closer to the front of the wheel. That makes the wheel design suffer, as this setup won’t allow enough space for spoke drops and deep lips. When the offset is reversed, however, there appears plenty of space for hub clearance, spokes and swooping.
Measuring wheel offset
There are 3 main types of offset:
- Positive. Wheels that have positive offset have the hub mounted toward the front side of the wheels. As a rule, such setup may be found on the rear-wheel drive vehicles.
- Negative. Wheels with negative offset, or so-called “deep dish” wheels have got the hub mounted closer to the back side of the wheel.
- Zero. That’s when the hub mounting surface is aligned with the wheel centerline.