Do I need new rims for narrower tires?

My first new used truck is a 2002 GMC Sierra 2500HD D/A, and I love it! But I'm a newbie so I still have lots of questions.

Factory tires on that rig would have been 245/75R16s but when I bought it it had (and still has) 265/75R16s.

I've asked and been told that I can, in principle, go back to the 245/75R16s the next time I buy new tires (which I'll probably do before winter). But would that also require me to buy four new rims? I seem to recall the 75 means that one part of the tire is 75% of either 245 or 265 mm, but I can't remember which part of the tire this refers to. Is the 245 tire as wide as the 265, or is it narrower, thus requiring different rims than I now have, for the 265s?

 

You don't need new wheels. Either size tire would be fine on the stock wheels. waytogo

 

Tom,
The 245/75 is the factory tire size. As long as your talking factory rims it's a perfect match!

 

Keep the 265's. 245's are tiny

 

Although the rim was made for a 245, I have to agree that it's to small of a tire for the vehicle. But that's a personal choice!