During our last blast of winter (with snow/ice being very unusual for the area), I got chains for the rear of my '08 2500 QC 4x4. Tires are 265/70R17E. The owner's manual states that chains aren't allowed on the front due to clearance issues.

I've looked and I really have to wonder where the clearance issue is at. Leaving that aside, it looks like it's OK by dodge to use 245/75R17E. The tire diameter is really close, so I shouldn't need to worry about speed/PCM changes. Anything else I should be concerned about?

Truck usage is daily-driver with some ~7,000lb trailer towing (plus ~800lbs of payload). The 4WD is really just for inclement weather, not serious off-road use (fractured vertebrae from "if you don't get stuck or don't break something, you aren't 4-wheeling", and the desire to not bang up a pretty truck).

Thanks,

 

If your area is uneusual for inclimate weather, then you are far away from needing tire chains! Just 4wd and slow down is all.
I believe tire chains will hit the upper control arm or strut mount.
I live in upstate NY, we get several storms every winter. Never have I heard of asnyone around here putting chains on their cars. You don't even see many studded snows around. Most get the studless.

I wouldn't put a smaller tire on your truck so you can put tire chains on for what maybe twice a year. You only need chains if you live on a very steep hill and you would use them to get up/down it and then take them back off.
Chains on just on one axle cannot be good for the 4x4, especially the front transfercase because you know the rear tires aren't going anywhere!

 

We are a bit unusual because we tend to get layers of ice/snow/ice/snow, and we are in a hilly area. ~25Mph on a major road, with chains, and the truck still got a little excited at one time changing lanes.
I need to look closer, more for curiousity than disbelief. The dealer, owner's manual, and even a tire dealer said no chains no the front.
I'm not going to run out and change things for an unusual event, but I want to understand the hows and whys so I can make an informed decision in the future if I need to.
This is actually my bigger reason for chains on the front; to try to keep slip/traction the same front and rear. However, the owner's manual says "rear only" (for these tires), which implies that rear-only isn't going to cause a problem.

Edit: Edited for a minor update; state/local authorities actually declared "chains required" rather than "chains carried" during part of this storm

 

They just shut down the roads if weather is too bad around here. Never have I heard chains to be mandatory around here, but then again, I'm in a city surrounding and that's more of a hilly and back country deal



Unless your front tires are constantly slipping with the chains on the back tires, your are putting a lot of stress on the transfercase and front axles. Something must give when in 4wd!!! So that means the front tires have to be slipping to make up for the rear tire chains which doesn't sound safe at all. Also, you must be plowing around any corner with those chains on. (pushing) Meaning your front end slides forward while turning, or at least more than usual because the back tires are grabbing and the front tires aren't grabbing as well plus they have to slip to keep the same rotation as the rears. The front are turning slower essentially and acting like brakes on the surface.
I would rather not use chains. I would say that studded snows are easier and much more leanient on your 4wd than chains.