The offset IS marked on the wheel, if you know the code. In the picture Carl attached, there is a pad at 3:00 with "ET 15" stamped on it. I can't recall what exactly "ET" stands for, but it really means "offset" in millimeters. So these are +15 mm offset, which will keep them nicely tucked into the fenders.

I found this explanation of "ET".

"Offset is usually stamped or engraved into the wheel and is measured in millimetres of 'ET' [ET is the short form of the German word 'Einpresstiefe' which literally translates as 'insertion depth']

Positive Offset wheels have their mounting face toward the front face of the wheel. Most front wheel drive vehicles have positive ET wheels. Eighties and Nineties Volkswagen wheels are usually ET38.

Zero Offset wheels have their mounting face even with the centerline of the wheel and are by definition "ET 0".

Negative Offset wheels have their mounting face toward the rear of the wheel - powerful rear-wheel drive cars often have wheels with negative offset".

Hi Arne/Ron:

Oops.. my bad... thanks for catching that.

4.125 inch backspace minus 0.5 for the outter rim thinkness = 3.625 inch.

the centerline of a 6" wheel is at 3"

so positve offset for the matting surface is 0.625 in or 15.8mm

FWIW,

Carl B.