Navy Lifer wrote: offset: +38mm - backspacing can be useful, and aftermarket tends to speak in terms of backspace instead of offset...although OEM's typically deal in OFFSET dimensions. With offset known, the backspace dimension can be calculated fairly closely, as long as the advertised rim width (bead to bead) is known, and overall width of the wheel, lip-to-lip, is known.
A +38mm offset means the mating flange surface of the wheel is 38mm toward the outboard side of the centerline of the wheel. If you were to take a wheel, measure it's width, whether bead to bead or lip to lip, and divide that in half, that dimension is "zero" when it comes to establishing the reference plane for measuring how far off of zero the wheel mating surface is. Now, if I've confused anyone....these were the top 4 in a search that goes on & on:
https://www.rsracing.com/tech-wheel.html
http://www.1010tires.com/Tools/Wheel-Offset-Calculator
http://www.ehow.com/how_5021837_calcula ... ffset.html
https://www.google.com/search?q=calcula ... 97&bih=545
Steve,
Looking back through some other wheel data, I ran across a note to myself--the stock steel (8" wide) wheels are +46mm offset, not +38mm.