The Stovebolt Site Forums The Shop Area Driveline Wheel offset

In reading several threads about wheel diameters, back-set, and offset I need enlightenment. I know where the diameter is measured and how to measure the back-set, or back space, but I have never heard of the offset. I plan to change the original 3 sp and torque tube in my 54 3100 to an OD trans plus open drive line using fairly narrow 16" wheels. Before I buy anything I need to understand the vocabulary

Calculation of offset is simple if you know the width and back-set. This calculator should explain:
Calculator

Thanks. Pretty simple, really, but first you need to understand that it is significant in the first place

Gord, your link comes up with something strange. Here's an explanation from Tire Rack The relation ship of offset and backspace is at the bottom of the page. They could have included it in the figure like the attached.

Offset is the distance from the wheel centerline to the mounting surface. The original wheels had zero offset or very nearly that.

Too far inboard (negative offset) or too far outboard (positive offset) from the centerline can put undue stress on the wheel bearings and spindles.

What Otto said. Another problem with positive offset is interference with things like steering arms, etc. If you put wider wheels on, even if the offset is the same as stock, for every inch of additional width, it puts the inside of the wheel 1/2 inch closer to the steering arms, etc. That can cause the tires to rub when making a sharp turn.

Here's a page from the 1951 Vehicle Info Kit that shows Tire and wheel info.