found this neat tire size comparison calculator- I was searching for an hour for a visual size comparison between a 175 / 80 13 trailer tire vs. a 195 75 14 tire. this chart is sweet to compare different sizes next to each other.

195/75-R14 vs 175/80-R13 Tire Comparison - Tire Size Calculator

 

That's a neat tool. Thanks for posting that link.

 

Another way to do it is as follows: If you have a tire that uses the metric measurements such as, 265/75-16 and you want to know the diameter, do as follows: 265x75 divided by 2540. Take that number and multiply by 2 and add the rim size, 16 in this case. That will give you the diameter.

 

oh sure, involve math why don't ya

 

Didn't mean to scare you off...