Re: trailer bearings which ones to use?
How tight is too tight? The old way was to turn the wheel around and while it was still spinning, tighten the nut until the drag of the bearing slowed the wheel down fast enough to notice. Then you backed the nut up one flat (approximately 60 degrees), and locked it in the closest hole with a cotterpin or just bent the lock tab over if you had that set up.
The new way is with a torque wrench and a specification chart.
The reason that the bearing is a little loose is that when you set it the clearences allows the bearing to get warm without increasing the preload to damaging point.
As a side note, whenever I stop while pulling a trailer, I always check the tire temperature with the palm of my hand and the bearing temperature with the back of my hand on the hubs immeadiately after getting out of the cab. The little walk around also lets me check the load bindings and general condition of the rig. It has saved my bacon. I also carry some Handi Wipes in the cab so I have no excuse!