WHEEL OFFSET

FROM the diagram on the left, we can see that almost all production-car wheels have a positive offset. It’s the opposite of how we usually talk about positive and negative offsets, but it’s how wheel-makers talk. It means that there is more wheel on the inside of the flange than on the outside, and the distance from the true wheel centre line to the mounting face is outwards and ‘positive’. This philosophy has been used by the manufacturers since the beginning of time to place the centre line of the wheel over the axle bearing, transmitting the wheel loads to the bearing directly.

The biggest issue for modifiers is the process of choosing a differential. Some modifiers choose a diff that’s too narrow for their vehicle, so they have to push the wheels out to fill the guards and avoid inner guard scraping. This usually results in over-track and illegal wheels. You can put your head in the outside of these wheels!

Others choose a diff that’s too wide and find that they’re unhappy because they have to run flat-faced wheels to squeeze them under the guards. Not the way to build a stunning-looking street machine!

The answer to this problem is to plan the width of your diff. It’s 2019; you can order a differential to be made to whatever width you want. Or you can select from the myriad production-car diffs available.