20" rims and no lift

What is the biggest size tire that I can fit on a stock 2008 TSS? I have 275's right now on 20" rims with a 3" leveling kit on the front.

 

with three inches you can get 33's on there. with no lift I think you can fit a 285/50/20

 

do i also need to put the aal lift on? the only thing i have is the front spacer. i'm looking to maybe go with a 275/65R20 set of goodyear mt/r kevlar

 

I would take it to discount tire and ask them. They will only sell you stuff that won't rub at all.

 

With a stock truck 285/50/20 and the correct bs and offset. With the 3" lift you could go 285/55/20 with the correct bs and offset

 

sorry to revive this, but what is the correct offset on stock with 285.50.20

are we looking at 4.5 still or higher?