I have a 2001 GMC Sierra 1500 and have 16 GMC stock rims but was given a set BF Good rich all terrain 315/70R17 tires in almost perfect shape. Would like to buy 17 rims for them. How do I make sure I buy the correct rim? My rims right now are 16X7, Bolt pattern is 6 X 139.7 M and Offset is 31. For the new tire, do i buy a 17 X 7.5? Is there something on the tire I can look for that will tell me the with of the rim?
315/70/17 tires will fit on a rim between 8.5in and 10in. These are the recommended widths for sizes. So no, a 17x7.5in wheel would not work. You could squeeze the tire onto a 8in rim and if you wanted that "bubbled out" look. You should be able to even get away with getting them to fit on a little wider of a wheel (10.5/11in) as well but I wouldn't recommend this.
Here is a list of wheels that are 17in and the same bolt pattern as your truck. Just look at the options of rims between 8.5in and 10in.
The remaining details and if you'll need spacers or not depends on if the truck is lifted or not, what kind of look you are going for. What you'll be doing with the truck (off-road/cruising). You could consult with the guys at americastire.com They're customer support is phenomenal. And the guys are extremely knowledgeable on their products.