I've got a White Industries sealed square taper bb, and was getting some noise, so I have pulled it apart and cleaned it.

Is it normal to pick open the seal and re-grease it, or should I just leave it alone? The bearings feel perfectly smooth, fwiw.

How do I know when they are spent?

Just as much info out there says that if a shielded or sealed bearing is suspect or needs grease you can and others say no way. I've cleaned and regreased shielded bearings. I've deduced that it comes down to the application and the industry it is used and that makes total sense. Is a bottom bracket or bike front wheel bearing the same criticality as one in a motor turning 3600 rpm 24x7 in a chemical plant or in the transmission in your car? People with cup and cone clean and regrease all the time for years. In principal, not much different here. It is the application!!!!

If me.. if the act of tearing down and putting back together the BB and cleaning and greasing any threads and all tightened back up doesn't resolve the creak or squeek, then consider the bearing regrease or replace. 6903-2rs are like $10-20 for a pair. I just looked up that BB, MSRP $130-180? Looks like a top notch BB.

I picked off the seals and flushed the old grease out and put some new Phil Wood grease in there. It is slightly more gritty now. (I suspect it will be fine once the new grease spreads around.)

It is funny that Chris King has extensive instructions on re-greasing sealed bearings, and it isn't even mentioned on the White Industries website.

This BB was $127. (The Titanium version is more.) The comparable Shimano lists for $25, and can be found for less than $20. I'll bet it is just as good, functionally speaking. The WI one is a very nicely crafted piece.

I just noticed on the website that, as you pointed out, it says "Bearings: 6903" which looks to be a standard one available for $10. I think I will order some, just to be on the safe side.

Why not go all in? Acer Racing Ceramic 6903 bearings, $10.99 each, ships from SoCal

Because as you likely know ceramic bearings are of extremely small efficiency benefit in a bike application, yet at a significant cost increase. Andy

That website is remarkably creepy.

Umm, the steel ones are $8-10 each unless you're buying them in bulk, and the ones from Acer are $11-- and they throw a 10% off coupon out to first-time buyers. So while I'm not a ceramic bearing guy, for the same price, why not?

Well, $10 is $5 below Phil Wood steel bearings. They aren't full ceramic, just the balls, not the races.

Besides, I generate an incredible amount of heat with my 30 RPM cadence.

Not all ceramic bearings are created the same. I'll take a good quality steel cartridge over an unknown ceramic any day

<snort> Okay, sure. Are we back to pretending that bicycles are F1 cars? ACER is where I used to buy the ceramic bearings for applications that actually required ceramic bearings-- electric motors that spin to +100,000rpm.

You could put literally any 6903 in a bottom bracket and run it for thousands, if not tens of thousands of miles. It's in an application that might see 120rpm. The only real advantage any BB bearing might have over another would be resistance to environmental factors.

The OP is getting noise out of a rather expensive BB after an unspecified number of miles. I have a Shimano Hollowtech II BB that was $22 and has around 18,000 miles on it, as quiet and smooth as the day it went in. This likely has nothing to do with the quality of bearings at all. OP maybe rides in more rain or dirt than I do.

There is a non-zero possibility that my "clunk" is not the bottom-bracket. It seems to go away when I stand up. The current bearings are fine. (In fact, they were smoother before I re-greased them, so I am worried I have done more harm than good. I haven't had a chance to re-test yet.) From what I can see, there was a lot of dirt, but it never got in as far as the bearings. It seems to spin more freely now, however. (I think it might have tightened itself up too much; at one point the lock-ring was a bit loose. Now I have erred on the side of a tiny bit of lateral play, which I may regret. Things I hate about square taper.)

Moving from Hollowtech II to square taper wasn't something I would recommend. I got it because WI 30mm spindle won't fit in my BB shell because a couple of Di2 wires loop through there. I'm seriously considering going back to Hollowtech II with the introduction of GRX (and 24mm spindles).

I've definitely popped the shields off of bearings to grease them. Sometimes bearings get made with no grease in them at all.

However, since popping a shield usually makes the shield not reusable I only do that for a short term fix.

Although, some short term fixes seem to last years.

I can see where some of their parts markup goes to.

Yeah it's daylight robbery lmao

If I was going in so far as to peel seals and regrease I'd just be replacing.

I think I will. But I already put it back together, so it will have to wait until I go through the painful deliberation process to decide which porn-star to ... I mean which ... I can't remember what we were talking about now.

maybe you can zerk it so as to fill the cartridge barrel with grease and push the old out past the seals..

I flushed the old grease with WD-40. Then I flushed the WD-40 with tri-flo. Then I let that dry and jammed in Phil Wood grease.

Took it for a shakedown ride. Original problem solved and it works great. I probably won't bother doing anything unless it acts up again.

I have a Touring bike frame built with BB shell* sealed, frame Tubes TIG welded to the outside

It has a whole lot of grease in between the bearings , only an outside seal on the oversize bearings ..

* was from the 90's era rear of a Burly Tandem frame components . Zerk in BB shell .. greased once 22 years ago..

They don't wear well in my experience.

Either set a maintenance interval or replace when worn.

Chris King has "an integrated grease injection system". For square taper BB's I find it hard to beat shimano.
I rode Phi Wood for years, but had to replace the bearings often. I made my own crude press to remove and replace them. The two shimanos' have over 25000 miles on them and still going strong.

so....why does he need ceramic bearings again? You can buy steel 6903 for like $2. I buy them by the dozens for cyclocross season

My previous experience with square taper is 37 years of malignant neglect. When I took it apart, it was still fine. Admittedly that was cup and cone, not tiny sealed bearings. (Crampy.)

I have no idea how long these are "supposed" to last. The BB tightening up a little I think was the source of my problem. If there was any damage as a consequence, I couldn't detect it.