I am wondering how big the 325/60/18 tire is? 33.5?? Thanks

 

Yeah, its about a 33x12.5 I think

 

33.3x12.8 to be exact, but it will always vary a little from different manufacturers

 

Here's some info on how to calculate:
https://www.f150online.com/forums/sh...height+formula

 

Yeah thats how I have always thought you figured it out, but I went on tirerack.com and they said to take the 12.8 and times by 50% and that will give you your height. And I did that and it just gave my height to the start of the tread, not the entire tire. So I guess it just depends on the tread added on. But I think that other formula 12.8x.60 works better, or gives you a more accurate number. If I did it by the 50% it only showed the 325/60/18 as about 30x12.8 so it only goes to the start of the tread. Thanks guys.

 

Your best bet is to look at the manufacturers website for the exact measurements. Sometimes the same size will vary almost 1/2 inch from one tire manufacturer to another.