I don't know much about rims, but I'm wondering will a 7 inch wide tire fit on a 6.5 inch wide rim or does it have to be a 6.5" tire? Thanks!

 

Tires don't come in a wheel 'width' per se. You can take a 215/60-15 and mount on a 6, 7 or 8" rim. It affects the height and the way the tire's sidewall buldges. Every seen those rollerskate looking cars with the reverse wheels and the tires look like they barely reach around the rim?..wrong sidewall height.

 

Check out the Tire Rack, they give all the dimensions for the tire size and even recomended rim width.