I saw this tire the other day and it was a size 315/70/17 and I was wondering about how big that was... Like if it was close to a 33' or what?

 

That's more like a 35" tire, though they usually come up short of a true 35".

 

34.4 x 12.4 / 17

 

A 315/70-17 is basically a 35x12.50-17 tire.

 

Those are about a 35" tire, but usually a tad bit smaller (34.6"), but they are a little more "fatter" than the run-of-the-mill 35x12.50 tire.

 

I just bought this exact size tire. BFG A/T KOs. They list two different tires in the 315/70 17. The difference being the speed rating and accepted rim size. The diameter is either 34.4 and 34.6

I could not find the All Terrrian tire in a 35x12.50-17. They only had that size in the KM2. I may be wrong.