Yet another tire and wheel question - I'm confused

[Rkimbrell]

I have read the FAQs, searched the threads about tires and wheels and just get more confused. So, apologize up front but need some help.

Truck is 2015 Ram 2500 Megacab Diesel with 20" stock rims.
I have a leveling kit that I have yet to install but could do so if I get off my lazy butt and get it done.
I am not real crazy about the Firestone tires that came on the truck and on my previous trucks (18" rims) I have always switched to Nitto Grapplers and had pretty decent performance.

What size tire and rim can I go with on this 2500 and not have an issue with rubbing if I do not do the leveling kit?

Same question, if I do install the leveling kit, what can I go up to. Do not have a problem buying different set of rims.

Thanks in advance.

 

[PassivAggressor]

I have no experience with 2500's, but in my bro opinion a 2500 needs at least 35's.

 

[SwollenMonkey16]

35s may rub without the level kit. my bro has a 2500 and those things are yoked. Id say throw in the level kit just to be safe. also if you're running stock rims you might need spacers but I have yet to run into a tire shop that wont test fit them. to worst case scenario just head up to the shop and ask them. these tires aint cheap so they'll do whatever you want to make the sale.