help, buying a truck with BIG tires

[jemrich]

I know this might not be the correct forum, but Im looking at a truck and need some help quick.
Im looking at a new, from the dealer, 08' 3500, dually that has 22.5 semi truck rims and tires on it. they are 36" tall.
I want to build a big work truck and will be putting a flatbed on it, I also tow a tractor, 10K, and 5th wheel, 9K. This truck looks very cool.
I am looking for feed back. Seems like a lot of tire but I know people run 36" or bigger tires? The tires stick out a couple of inchs past the wheel wells in the back now which will make for a 100" wide flatbed.
How big a tire are people running and how wide is the rear wheel set?
Also the truck has 3.73 gears which seems to be what all the automatics have. Any issues, should I look for 4.10's?
My option seems to be 19.5 wheels and 225 tires? maybe 32" tall, I like a little bigger.
Im negotiating around 37K plus 3.5K for wheels and tires.
This truck looks very, very beefy as set up, but....