I would need a lift for those. I am pretty sure I can get away with 35's on the stock suspension, any larger though, and they are gonna start hittin' stuff.

 

Shiny or white roads = 4x4.
I second the DuraTrac nomination. Outstanding tire in a 10ply. Excellent off road, wet, packed snow. Foundered a bit in the deep snow we got into our place in B.C., but that's the price of a second winter on a wider tire. Got lazy on the rotation, so fast driving on Texaz gravel upset the wear, but I run a 5wheel rotation and I'm not unhappy. I ran off 3 sets of the SilentArmors before GoodYear quit them. Tire shop offered DuraTracs because they were having good luck with them on the mine roads. I liked them so much I bought the 285/75-18 for my 2500. Tallest tire I could get without going stupid wide. Any parrot that tells you a wide tire lets the truck 'float' over the snow doesn't drive any serious winter. Flotation is fine until you need to steer or stop. Sliding into a sharp corner at the bottom of a steep, snowy hill requires 4x4, limited slip, and the (counterintuitive) application of a good amount of power. You'll be happy your tires bite.
This thread seems to have wandered, I'm guilty.

 

DuraTrac is available in two versions, with and without the little Mountain Snowflake, Snowflake is studdable, other is not. RCMP seems to be wound a bit tight sometimes, so I run Snowflake as req'd on Canadian winter highways. Don't need anybody telling me I need to stay home.

 

They make a 35 would be the same tire as mine but smaller