Hello, this is my first post on this forum, I am currently building a CR750 replica (well look alike at least) using a 1977 K7 as a base, I have seen some good value rims on ebay but I'm not sure what rim width to go for, I will be fitting 18" rims front and rear, I seen a post that recommends WM3 front WM4 rear but those sizes don't mean anything to me, does WM3 = 3inch rim width and WM4 = 4"?, cheers Mark.