OK time to get on my soap box
Who cares?
different diameter tires on 4WD is Very bad for the drive train and dangerous
different brands and types of tires have different diameters (yes even the same size tire) and since he seams to feel that rotating the tires will help his problem of sliding around in 2WD
I can only assume that his front tires have more tread than his rear tires.
Do you still say so what?
When in 4WD have you ever turned a sharp corner, what does the truck do?
well your front wheels are going around a circle and your rear wheels are going around a slightly smaller circle.
the same thing as running different tires front and back and going in a street line.
Example
with tire A in the front and tire B on the rear.
the actual diameter (not size) of tire A is 31 inches, The actual diameter (not size) of tire B is 30"
Different diameter tires travel different distances per revolution. Since that gears in the front and rear differentials are the same (again I assume). say 3.07 every time the drive shaft goes around ~3 times the wheel goes around 1 time. So for every wheel revaluation, the front wheel travels 97.38 inches, the rear travels 34.25 inches. thats a difference of 3.13 inches Thats not a problem in 2 WD. If your in 4WD the drive train connects the front wheel to the rear wheels. What happens to that extra 3.13 inches the front wheel wants to travel MORE than the rear wheel. a lot of stress on the drive train, until a tire slips to take up the difference distance that is 31.3 inches every time the front wheel goes around 10 revaluations or every 75 feet the rear tire gets dragged about 3 feet. or the front tire skids the 3 feet.
now the way it works is it does not wait until 3 inches builds up but happens constantly a wheel HAS to SLIP or SKID to make up for the difference in travel
So we have an axle skidding all the time once a wheel is skidding it looses traction in ALL directions. Like when you are going around a corner and slammed on the brakes the car (or truck) skidded strait. Thats why its dangerous.
Now we'r not locking up a wheel or using a 10 inch wheel up front with a 30 inch wheel in the back. The problem is proportional, the bigger the disparity between the wheel sizes the bigger the problem.
For all I know the actual diameter of the front load range C tire with more tread is the same as the rear load range D with less tread. But unlikely
OK I'l get off my soap box
Thanks if you read the whole thing.