I would offer up that there is not ENOUGH of those "numbers" listed when it comes to buying wheels. The fact is that those numbers are EXACTLY what you need to tell you precisely how a wheel/tire combo will fit your car. In fact, it's impossible to know how a wheel will fit your exact car without those numbers unless you find someone running the exact wheels and tires on the exact car with the exact same configuration. If they have differend brakes, you won't know. If they have different fender flares, you won't know. The list goes on. Yes, you can genericaly say a wheel "should" fit your car. But if you want to know if it will rub inner fenders, if it will interfere with brakes, if it will poke out 3mm or be recessed 6mm, you can't know for certain until you measure your car's reference points and then understand what offset, backspacing, etc means. Heck. If you know the numbers, you can make a fake wheel and tire out of cardboard and do a test fit before you even buy the wheel. 

Really, if you want the best fit and exactly what you pictured in your head, you have to understand the numbers (you'll pick up on it relatively quickly if you watch a few youtube videos) and then measure your vehicle. 

Sorry, this website's format won't allow me to hyperlink from my phone. And it doesn't automatically convert url's to clickable hyperlinks, so you'll have to copy paste. 

//www.tsw.com/explore/what-is-wheel-offset.php

I'll try to post more info when I get home. 

good thread, very informative, still awaiting for my wheels to arrive ,, uhm hope soon... ehem!

Thanks Cupcake.  Great info.  I think I have a basic understanding now.

Jack

//www.wheeldictionary.net/

When shopping for wheels what numbers do you look for if you want the wheels to stick out an inch of two more than standard fit?  Often times there is no indication of how the wheels will fit only a number like ET13 or such.

 Can someone give me a quick explanation of wheel offset numbers and what they relate to?  I know they are used to select wheels that widen the stance of the car, but I don't know what the actual numbers mean.

Jack