Wheel backspacing and offset

[Cannoball888]

Can someone explain the difference? Thanks in advance.

 

[BobV]

Backspace is measured from the back edge of the wheel. Offset is measured from the centerline of the wheel.

This chart shows OFFSET (in mm) for various wheel widths and backspacing:

 

[Capt Dan]

This chart shows OFFSET (in mm) for various wheel widths and backspacing:

 

[ForceFed70]

Backspace is the measurement from the wheel mounting surface to the wheel lip on the back side of the wheel.

Offset is the measurement of how far the wheel mounting surface is from the center of the wheel.

0 offset on an 8" wide wheel would mean the wheel has 4" of backspacing

 

[BobV]

0 offset on an 8" wide wheel would mean the wheel has 4" of backspacing

Not exactly...
Backspace includes the thickness of the wheel lip, which is usually ~1/2" front or back. An 8" wide wheel (as measured from inside-lip-to-inside-lip), actually has a TOTAL wheel width of about 9". So, for 0 offset (meaning the mounting face is centered in the wheel), the backspace would have to be 4.5".

 

[ForceFed70]

Not exactly...
Backspace includes the thickness of the wheel lip, which is usually ~1/2" front or back. An 8" wide wheel (as measured from inside-lip-to-inside-lip), actually has a TOTAL wheel width of about 9". So, for 0 offset (meaning the mounting face is centered in the wheel), the backspace would have to be 4.5".

Doh.. your right, I keep forgetting about the stupid wheel lip. Thanks for pointing that out.

 

[Cannoball888]

Thanks for the explanation. It's really helpful. I need to start thinking about some new wheels that'll fit the new 9" that'll be arriving soon.