New Sierra Denali HD 2500 - upsizing stock tires/wheels?

qchunter... thank you. We absolutely LOVE the truck.

We won't get the Airstream for about 8 weeks, so no idea on the truck squat that it will create... I don't think it will squat very much.

The dealer told me that they could adjust the speedo for larger tires, but that it would still be off by about 6 mph at 60 mph. I'm not liking that.

The factory stock tires are Goodyear Wrangler SR-A LT265-70-18. E-rated. I'm thinking we'll just run these tires until they're done and then, perhaps, go with a fatter set of 18"ers.