@ABMax24 and
@Ashful are killing it in this thread. The only tire pressure gauges I trust are dial type that hold a reading and have a release valve. I want the midpoint reading on the gauge to be 30-35 psi, so range on the dial 0-75 or 80 psi.
The free tire pressure gauge from your bank or barber shop with the sliding white plastic rod is worse than useless. Don't accept it as even a free gift. If you must, smile, say thank you and drop it in the nearest trash receptacle after you leave the establishment.
In general, all other things being equal, a higher pressure will give your tire better side bite, while a slightly lower pressure will give the same tire better front bite. If you are competing with a front engine rear while drive vehicle on dry pavement, this is easy. If you have a pick up truck in 4WD on snow you need all the bites all the time.
You can't go very far down this rabbit hole without needing a pyrometer to measure the temperature of the tread blocks, inner, middle and outer on all four tires very rapidly when you pit and the tires are still hot.
For the OP, I would go with 32psi on all four corners for now since the truck is rarely used at capacity. Next, take pictures of the treads with your phone every 1k miles or so. Just back up (zoom out) far enough that you have enough vehicle in the picture to know which corner you are looking at, but put the focus point on the center tread block. Most likely, on a lightly loaded truck, you will first see wear on the inner tread bands of the front tires. In general truck manufacturers put a lot of camber on the fronts, they tip the tops of the front tires in towards the engine a few degrees, so the fool thing with no load in the bed can turn a corner without a lot of drama. It makes the truck easy to drive, but it is very hard on the inner tread blocks of the front tires. You get to 5k miles, rotate front to rear on both sides, get on with your life.
When you get to 10k miles and it is time to rotate again, it might be time to see how much it will cost to rotate left-> right instead of front -> rear. If you have asymmetric (directional) treads, you will have to dismount and remount all four tires to rotate L->R, but that will very likely put very good tread blocks in the high wear position at (usual suspect) front/inner, and be less expensive than replacing all four tires.
The chalk method advocated by
@mellow is extremely effective, but you can sometimes see results in 10-15 feet and then have no usable data if you roll the vehicle 50 feet. I didn't watch the video, BTDT got the T shirt. I'll go start the video. Mellow, well done. With a different vehicle that dude could be competitive at Sonoma. I personally would chalk up about 75% of the tread blocks. No big braking, no burnouts, good advice. But I would also only roll about ten feet and be looking for chalk to already be missing from the front inners - long before the chalk was gone from the front outers.
In general if the OP leaves his tires at 38 psi (s)he is probably going to have perfectly adequate side bite and likely less wear on the front inner tread blocks compared to running at 32 psi x 4 corners. Gas mileage should be pretty good. Front bite on the rear axle in 2WD on dry pavement is going to be abysmal. Performance (all parameters) on snow and ice (@38psi) will invoke the poorer tasting anatomy of an angry donkey.
One compromise would be to run 38psi summer and 32psi winter.
Good luck and best wishes.
