Rim diameter has nothing to do with tire height.

 

Right, I agree there. I have seen it posted here a few times that a truck that has the 20" wheels will sit 1" higher (I think) than the others due to the height of the tire on the rim. Is that true?

 

It depends solely on tire size. You can have a 20" tire that is 22" tall, or you can have a 20" tire that is 40" tall.

 

The 20" rims come with the largest diameter tires, about 34" tall. The common 18" size is about 33" tall. Remember that "height" is only affected by the amount of tire below the center of the axle, so divide by 2. That means the 20" tire trucks are only about 1/2" taller than the 18" tire trucks.

 

That's what I was looking for, thanks.

 

Definitely cheaper than the repair bill when you cross the threshold with a little more bounce then normal due to a stone/snow/ice/speed and crease the cab roof...