Tire sizing

[Thb341]

Hi everyone,
I have a 2019 new model ram 1500 sport. The truck came with 275/55R20 and I'm looking to upgrade these. Currently, I'm looking to keep the factory 20inch rims. The truck has no leveling kit/lift/air suspension.
I'm wondering what is the max tire size I can run on stock body?

 

[mxz]

I also have a Sport with stock everything. I am running 305/55/20 BFG KO2's with no issues.