@boxster:
I think that's a lot of bla bla from Pedro.
There are a lot of different kinds of bearings made for special applications. Also there are different quality grades available. He also didn't name manufacturer or type, nor the specs. So you can't say that ceramic is bad and metal is good. That's complete bulls…t.
The bearing has to the right one for the application. I did some research on that a while ago. And i'm pretty convinced that there are ceramic roller bearings that won't fail within the given specs. But these are not the china cheap ones.
A sealed bearing is always the better solution. Problem is the under- / overpressure in the tube. Oil feed has in my opinion some disadvantages. Oil has to be clean and you can't prevent to swap uncleaned oil from the oil pan to the bearing. An oil line can break. Also there will be oil in the tube.
So in my opinion the best is to solve the under- / overpressure problem first.
That's not against Jake's or Pedros or any other solutions. They work, but you'll have to do a lot of oil changes and the solution won't work for a life time. So you'll have a lot of follow up costs that i don't like.
Regards
Markus