I stumbled upon
THIS page from PartsProvider.net while searching for rims that would fit my '93 Excel. Although this link will bring you to a 15" rim that they are trying to sell @ $169.99 ea, it gets pretty in-depth about nomenclature for describing a rim including offsets and back spacing. Scroll to the bottom and feed your brain. I hope this helps. Keep us posted on what works for you. Its time for new rubber on mine so upgrading is on my list too.
(IMG:
http://www.partsprovider.net/images/wheel-offset-backspace.gif)
Here's a "cut-and-paste" of the same URL just incase the link above doesnt work...
www.partsprovider.net/hyundai-excel-accent-sonata-buick-inch-rims-p-78.html
ADDITIONALLY: An in depth document specifically on tires
HERE. It's a bit of a read with no pictures.
This post has been edited by milk8man: Aug 21 2008, 10:39 AM