I'm selling my18" Acura TL A-Spec rims and was asked if they are 7", 7.5", 8", or 8.5". The tires I have on are 225/45ZR18 and I've read that 40's are better for 8.5" but 45's are still possible. I had them redone so I can't seem to find any print on them either...how do I measure?

 

Normally the width is cast into the wheel somewhere, not painted. For example 18x7.5J ET48

There's a picture here showing what to measure.
http://www.tirerack.com/wheels/tech/....jsp?techid=95