How to Measure Rims

[anthony605]

I have a friend that wants to give me a pair of 15 inch rims off of his 2 wheel drive blazer. They are ratty looking but perfect to drill for slicks. Now, how do i measure backspacing? And, how is width measured. Is it bead edge to bead edge or is it the center section of the rim? Thanks

Anthony

 

[UNGN]

Backspacing is the back side of the outer rim lip to the mounting face. Rim width is measured on the inside of the rim beads.

 

[anthony605]

for backspacing, when you say outer wheel lip to mounting face do yo mean the outer lip that igoes towards the inside of the car to the flat spot that mounts to the hub?

 

[UNGN]

Yes. The furthest inward point on the wheel to the bolt flange face.

Backspacing is actually a dumb measurement. Wheels can have identical offsets and widths, but have different lip thicknesses so the backspacing is different.

The tire bulge will hit the frame before the rim, so offset is more important than backspacing.