my 97 silverado is in need of a new set of tires and what it has now is 265/75-R16, now i dont entirely understand all that ratio mumbo-jumbo but as far as i can tell that is close to 32x11.50. i was wondering if i could fit something that would be 33x12.50, 33x11.50, or 32x11.50 without rubbing. would that be close to 285/75-R16 or 305/85-R16? cuz most all the tire sizes for a 16 inch rim is incripted in ratio....

It's actually even more complicated than that!

Your truck came with P metric tires - on 7" wheels. All the sizes you mentioned are LT's.

If you are planning on using your stock wheels, I'm afraid the size you have - P265/75R16 - is the largest that will fit.

If however you are planning on changing wheels, here's a calculator to help you with the diameters and stuff.

http://www.1010tires.com/TireSizeCalculator.asp

Hope this helps.

Yes, they maxed the tires out on that rim package from the factory. Anything in the 33" rang will require a lift kit of some sort.