The Wheel Offset is taken from the wheels centre line and measured to the mounting face of the alloy wheel; all alloys have a different mounting face, so in turn the offset for each will be different. There are two main offsets Positive and negative. The majority of modern vehicles have a positive offset, and older vehicles and SUV’s tend to have a negative offset, it is important that you ensure the wheel and tyre is going to be clear of any bodywork, suspension, steering and braking components. It’s usually accepted that you can go 5-7mm outside the recommended vehicle guidelines although the further you go past the recommended allowance the more the performance will be affected.
Two Main Offsets
The mounting face of the wheel is forward of the centre line meaning you have to push the alloy further into the wheel arch before you can attach the wheel mounting face to the Spigot, therefore bringing the wheel further under the bodywork of the vehicle to connect.
Negative Offset :
The mounting face of the wheel is behind the centre line so when connected to the spigot the faceplate will have less distance under the wheel arch and the wheel will be pushed outwards from the vehicle bodywork.