Can I run different tire sizes on the fronts and backs temporarily? like maybe for a month or two

I need to get two new back tires now. new backs would be 275/70 and front would be 275/65 until I can get those upgraded.

This is a 4wd truck- would only be running 4wd if on dirt/mud

 

Running in 2wd won't be a problem. I wouldn't use 4wd at all until you get the fronts replaced. If it was me, I would have swapped front and rear tires until you were able to get a new set of 4.

 

I am not sure exactly how these 4x4 systems disengage but there is about a 1 inch height difference in those two tires, I would highly recommend against it, especially if putting it in 4 wheel drive. In 4WD the smaller tires will have to turn faster than the larger tires and this will put stress on the drivetrain and could result in damage to the transfer case, differentials, ujoints, etc. If they disengage at the front hubs (which I think they do) you would be fine in 2WD, don't do it in 4WD.

 

Hi,
I wouldn't put it in 4wd at all.
I've heard it'll effect the ABS,
You can never tell when you'll need to jump on the brakes.

 

I would not use 4WD for sure.

I'd get all four tires now or if you really can't afford that, get same size replacement tires two at a time and you'll just have to stick with the same size.

Or at least leave it in 2WD, not auto or 4.

 

If the ABS system constantly senses a different rotational speed between the front and rear it will throw a code and likely de-activate ABS, stability and traction control functions. Even off-road I would not ever run in 4WD with different sized tires.

I wouldn't ever do that on any vehicle with ABS or 4WD.