Cartridge type BB - how to maintain/when to replace?

I'm just starting to get into bike overhaul and have just taken apart my Ultegra 6600 crank. The BB assembly is called Hollowtech II, and the bearings are in cassettes. I've done the usual wiping off of old grease and grime from all of the parts. However, I'm not sure what to do about the cartridge bearings, other than wipe the outside and use a tooth pick to scrape out sand that's gotten into the space between the cartridge and cone. It says, "Do not disassemble", which I assume means the bearing cartridge should be left in the cone. One of the articles on-line said something about having to just replace the BB entirely when it gets old, rather than taking it apart for cleaning and regreasing.

Is there any further maintenance I can do on the bearings? Should I inject grease anywhere or try soaking in solvents? How often should this part be overhauled for cleaning, and how often should it be replaced? Someone recently told me that it should be maintained every 5K kms (assume 3-5K/yr level of riding). I've gone 10K with no maintenance and am wondering if it is time to replace the whole thing.

Any advice / guidance / direction to helpful link would be much appreciated.

Thanks,

Nothing to maintain. Like BB bearings from shimano for years, when they get gritty, or loose, you throw them away, replace. Now, it IS possible to disassemble these cups with a Phil Wood tool kit and replace the bearings with something better but at $40 + labor to do this, it may be cheaper to just get a new one.

Biggest 'issue' is that the BB shell MUST be faced, the BB shell must be greased along with the crank spindle and the whole thing assembled correctly and to torque.

Do NOT soak these in degreaser/solvent.

By "BB shell", are you referring to the metal cylinders on the left/right sides that hold the bearing cartridges? Also, what do you mean by getting them "faced" and is it hard to do?

Thanks for the help.

As far as I know facing (and thread chasing) are steps best mainly required when a fram is built up for the first time, or perhaps if it's been repainted. It's a minor machining of the rim of the BB to ensure that the cartridge settles evenly.

facing the bottom bracket shell should not need to be done when replacing the BB

if your BB has been running smooth for 10k then the faces of the shell should be OK

i never replace a BB unless the bearings are rough or has play at the crank, one of my oldest shimano cartridge units is going on 15yrs, still smooth

although if it is inconvenient to disassemble or have the bike apart for repair this may be an opportune time to swap it out

good luck

I am familiar with facing as relates to the frame i.e. machining the two end faces of the cylinder that holds the BB to make them parallel (via the Park Tools web page). I assumed this was already done by the frame manufacturer or at the LBS. If the BB needs replacement, I was hoping to just purchase the same one and simply install it, not having to worry about further refinements. If you know from experience that this is a poor assumption, please share.

One more question - are there third party BB's that are compatible with Shimano cranks (Hollowtech II) and that anyone would recommend over the BBs made by Shimano?

Thanks again,

Not a good assumption to make. It's certainly not expensive to have an LBS check to see if your BB shell needs facing or even to have the actual facing done. It's a very quick process.....5-10 minutes.

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It is debatable that Phil Wood bearings are better, but most would agree that they are at least as good. Most of the others are a notch or so lower. My FSA started to go south around 6K miles.

All bicycle frames should have the bottom bracket shell(where the BB bearings live) faced, that is, the two surfaces that the bearings sit against be made parallel.

NO guarantee the frame has had this done, a competent bike shop can do this and the bearings, regardless of manufacturer, will last longer.

But if the bearings turn smoothly in your fingers, the crank isn't creaky, noisy, grease 'the shell innards, the crank spindle and reassemble.