hatman,
got to tirerack . com.
after you get a tire, look for 'specs' they list all the measurements etc.
also all the tire sizes in that particular 'model'. it is a great resiurce.
here is the specs page on the 215/70/15. scroll down to see all the sizes for this model tire
http://www.tirerack.com/tires/tires....=yes&tab=Specs