Even for those who know quite a bit about cars there can be many unknown factors that affect a vehicle's performance. Most people know, for example, that the tires that are used on any given car can have a large impact on its performance. Fewer know, however, that the wheel offset can also have a large effect on performance.
Wheel offset is, quite simply, the distance from the hub mounting of the wheel to its true centerline. In other words, the offset of a wheel is the distance between the place where the lugs connect the wheel to the vehicle and the actual middle (from a vertical perspective) of the wheel.
There are three potential types of wheel offset including neutral offset, positive offset, and negative offset. Neutral offset is also sometimes referred to as "zero offset" and means that the hub mounting of the wheel is directly aligned with the true centerline of the wheel. Positive offset means that the hub mounting is closer to the front of the wheel (closer to the outside that faces the street). Negative offset, on the other hand, means that the hub mounting is close to the back of the wheel (closer to the inside that faces the vehicle).
The effects of wheel offset have mainly to do with the forces that are exerted on wheel-bearings. Most manufactured vehicles come with a wheel offset that is designed to minimize the load on the wheel-bearings. In a vehicle with poor wheel offset many problems can manifest. Badly offset wheels can cause handling problems, break parts, and even cause catastrophic failures to occur. Properly offset wheels, however, improve handling and decrease component wear and tear, especially while cornering.
Sadly, it is impossible to give all-encompassing advice regarding wheel offset. This is due to the fact that each vehicle model has its own unique characteristics. Because of this, some vehicles respond better to positive offset and some to negative offset. Also, the offset that is optimal depends largely on what the car is going to be used for. Cars that don't have to worry about cornering capabilities will benefit from a different offset than identical models that are frequently involved in tight cornering. The only way to determine what's best for your car is to research the matter and to contact your manufacturer for advice.
Wheel offset alteration can have serious effects on the handling characteristics of vehicles and on their safety. Always take due precautions when altering your vehicle's wheel offset and make sure that you know what you're doing before attempting it. Remember, a vehicle with extremely poor wheel offset can suffer catastrophic part failures which can lead to accidents, particularly at high speeds.
