I don't think it'll be a problem for the truck. It might cause a slight bit of binding in the drivetrain if you have and use 4wd.

 

Hi Dave, and welcome to the forum! :thumb:

First we'll talk about one axle, the rear. Running different size tires on an "open" axle (one with out a locking mechanism) won't hurt anything mechanically. On a differential with a locking mechanism, it can cause problems. If the differential is locked, the difference in tire circumference can cause one tire to drag trying to keep up with the other. This not only causes wear on the tire, but wear on the differential too. The G80 locker that GM uses in the rear allows up to a 100 RPM difference in the wheels before it locks.

On the front axle, if you have two wheel drive, running different sizes may make the truck handle weird, but that's all. With four wheel drive,, unless you have an aftermarket locking differential installed, it still won't make a difference as the factory using allows both tires to spin independently of each other.

Front to back. On a two wheel drive vehicle, you can run different size tires on the front from the rear and have no problems. On a four wheel drive, you still get by unless you put the vehicle into 4 wheel drive, at which time, you will experience similar problems those stated in running different size tires on a locking differential.

 

Not a 4x4

 

If each side is even Steven, then when would the locking get engaged unnaturally?