[Motor31]

I believe that Doubletree specs sealed bearings from Dexter axles on their rigs. That's what it looks like to me. There will be little leakage from them if they do fail since there isn't that much grease in them.

You were very lucky to have caught it when you did instead of having a wheel separation in motion. I'd bet you will need a full spindle replacement as well as the bearing.

What kind of brakes do you have on the rig?

When traveling I stop more than once during the day and check tire and hub temps each time I stop. It takes just a second to put the back of my fingers against the side wall and hub to see if any wheel is running hot. Since I have over 4 years on the rig this last August and over 20,000 miles on the trailer I am thinking about swapping the bearings as a preventative maintenance operation this winter. I would hope that they would last longer but I'm not going to assume they will.