This might be a ridiculous question but I want to confirm I understand this correctly. I was looking at the back of my Nissan Truck 1986 Service Manual where the wheel and tire specs were and I saw that for the 4WD it had P215-75R15 size tires for the Front and P225-75R15 size tires for the Rear so my question is am I understanding that the front and back are different sizes or that these 2 were options for the 4wd Truck? If they are different sizes what is the benefit of this for 4 wheeling, I'd like to think the bigger tire would provide more grip offroad, am I wrong? My reason for asking this is because I want to bring this truck back to stock to see what it was originally made of and how it felt, so I am going to start with the wheels.
I have been told that different size tires will mess up the gears in the differential because the smaller wheel
is spinning faster than the bigger one.
Running same size tires are important when you have 4x4 engaged and have traction, it "could" bind up some stuff in the T-case.
That sounds about right I was just a little thrown off a little but what I saw on the book, looks like I will probably just stick to the 225's then. Hey if I remember right, are you running 235's?
What ever you run, run the same diameter. You can run wider on the backs than the fronts or all 4 wider than stock but keep the diameters the same.
Larger diameter tires increase your overall gearing making it harder to crawl up hills in 4wd. The '83 and up 720 is already hampered by 4.11 differentials where the Z22s were a nice 4.375.
Stock '83 and up 720s came with 215/75R15 tires. If you install 225/75R15s your over all gearing drops to 4.02 if you go 235/75R15s it drops even more to 3.93. Degrading the already poor acceleration and crawl ability of a 4x4, ok on the highway.