those are only numbers....they usally areclose but not exact to actual size...measure them like i said then you will know the actual height difference

 

Here's another calculator for ya

http://www.miata.net/garage/tirecalc.html

 

You just have to put big wheels on these Rams or they look like they have their 'pants' down with all that wheel well in back. I run 265 75 16's I guess I should put on some sort of highway tire, butI like the aggressive tread.

 

When he set it next to yours, was your truck on a lift with the tire in the air without a load on it, or was your truck on the ground with the weight of it on the tire? If your truck was on the ground with the truck weight on it, this would cause your tire to appear shorter than if it were not under a load. Just a thought...