I have been looking at tires for so long I'm confused...

I want to run a 33x12.5x16, what are the normal tire specs for that?

 

I don't think that is a sandard size tire anywhere. I may be wrong, but that specific size may be hard to find and/or very expensive special order. Just seems like a wide version of a 33 inch tire.

 

12.5 is typically the most common width people run in a 33,35,or 37" tire.

 

Yup, 305/70/16 - super common, easy to find, and a 33" diameter tire with ~ the TREAD width of a 12.5" section width tire (Its closer to a 12" section width, but because the aspect ratio is lower, the TREAD is wider, and the TREAD width is what gives traction/flotation, etc....so that's the size you want.

I held a set of 33 x 12.5/15's to a set of 305/70/16's....the 305's were slightly taller (A true 33"), and had a slightly wider tread than the 12.5's in the 15" size.

Some 35's and 37's give the same specs for a 315 mm section width as for a 305 section width...so, essentially, in a 33.....get the 305/70/16.