Hello from Hong Kong to everyone!
I'm new here and recently got a Grand Cherokee Summit 2014
Enjoying the car very much i have to say!

I need some help about tire size swap:

Currently my car is mounting 265/50/R20 (Tarmac regular Tires) i would like to swap to AT Tires (for Sand/Mud/Gravel). without necessarilt change the Rims R20 which i like.
locally i would be able to purchase AT tires of the following size:
265/60/R20 or 275/60/R20 (which are same quality but more affordable)
Assuming that i don't want to do any kind of trimming and don't want to have any rubbing, i can lift the car with an airlink set up to 3" (the car has Air suspensions) and/or add spacers if necessary would i be able to use one of the sizes of tires above mentioned?
if need to lift how much? If need spacers what size?
anyone can help to properly calculate?

thanks in advance for your help!

AntiqueTango.