Re: Wheel Offset vs. Backspacing
Back in the late 70s, through the mid 80s, I used to sell custom wheels and tires, in order to finance my automotive hobby. And I'll be the first to say, that MANY times, I wished the wheel manufacturers would use EITHER backspacing OR offset, BUT NOT BOTH!!!
I'll try to help......
Backspacing is the dimension that's measured from the back side of the wheel's mounting pad, to the outer edge of the back of the wheel.
Offset is the dimension between the backside of the wheel's mounting pad, and the centerline of the wheel. This gets tricky, but let me use an example, to try and illustrate this.
A rim might be called an 8" wide rim, for example, but that isn't the OVERALL width of the rim. The overall width of the rim is closer to 9", because the inner and outer beads add about another inch. The "centerline" of the rim, measured from the outermost edge, therefore, it would be 4.5". IF the backside of the mounting pad is 4.5" from the back edge, then the wheel has "zero" offset.
If the mounting pad was 5" from the back edge, the wheel would have 1/2" positive offset. If the backside measurement was 4", the wheel would have 1/2" negative offset. Problem is, because most of the wheels are now made in places other than the USA, the offset measurement is expressed in a metric number, which is confusing for many of us.....