[A/S] Wheel Bearings

[David@xxxxxxxxxxxxxxxxx]

A friend of mine and I were talking about our trailers
today.  The subject of annual wheel bearing packing
came up.  He asked why you had to pack trailer bearings
every year when you can drive a truck year after year
and NEVER pack the bearings?

OK, maybe they are packed when a brake job is done,
still, that would be once every four years and 60000
miles.

I have had several vehicles with well over 100,000
miles each and three vehicles with well over 150,000
miles each and I have NEVER had ANY wheel bearings
packed (unless it was done with brake jobs - I don't
know about this).  Yet I have never had any bearing
failures on any of my cars / trucks.

Is this a conspiracy or are trailer bearing somehow
inferior to those used in cars / trucks?

Also, a few years ago I restored an old utility trailer
that my brother had made in high school.  This trailer
had sat in my mom's backyard for at least 15 years. 
When I pulled the wheels off, the greese inside looked
fine.  I did, of course, pack the bearings.  However, I
think it might have been fine with the grease already
there!

Any thoughts?

David Robertson