Just my preferences - other guys think differently:
- I have always followed Ram's recommendations and they work fine for me. Some guys want a lot more pressure, but I prefer the front wheels to be less twitchy when pulling a load. When the front's aired up higher than 55psi, it tends to steer too easily, much easier to end up straying into other lanes, etc.
- The back end of the truck is lighter than the front. With a 1/2 ton load in the bed, it doesn't even tend to compress the tires much at the recommended 50psi. Most trailers should put less weight on the tongue (back), so I have even less reason to want to air it up more. Plus the back tires tend to leave the pavement easily with road bumps and potholes. Higher pressure tires get harder, just making that even more likely, which is really bad when towing, especially on curves.
- Airing up your tires makes them harder, and less tire is touches the road. I like more rubber in contact with the road, especially when braking. But there are other reasons, too. Trailer tire failure can result in situations where you'd really want a lot more rubber on the road to stabilize the truck.
- Normally there is no difference at all for the front tires. Trailers load up the rear tires by tongue weight, which is behind the rear axle unless you're 5th-wheeling. You do get some front tire loading in hard braking, but if you're braking that hard, your bigger concern is going to be skidding. And again, more rubber = reduced chance of skidding.
There are always guys that will tell you you need more tire pressure. But these are E-rated truck tires, not passenger tires. They're already designed for heavier loads and have stiffer sidewalls than the tires Ram puts on a lot of the other 1500s.