OK, so I know there sealed for life, but one of my shimano external BB's is pretty stiff to turn. Not so much gritty feeling or worn, but stiff enough to worry about the crank shaft spinning in the bearing and wearing rather than the bearing turning as it should.

I'm supposed to be riding this weekend and getting a replacement is not going to be easy, so I just tried dunking the think in a drum of reasonably heavy weight oil at work and gave it a little working round with my fingers until it freed up a fair bit.

It feels pretty good now, but I wondered if anybody else has any servicing tips for these things? if anyone’s tried the same and how long did it last? and I wondered if anyone can tell my if they're a touch on the stiff side when new due to all the seals?

I'm wondering weather to chance them for the rest of the winter, or get a spare set in. If so what? Cheap as you like disposable ones or perhaps hope ones? what you would you suggest?

You can service the bearings yourself – press or knock the sealed unit out, and carefully prise off the plastic shim bearing cover. The easiest thing to do is press a new sealed bearing in, with bearing retaining fluid. Most siszes are available from "Enduro" or on EBAY. The size will be written on the rubber seal.

You can replace the balls in a sealed unit if the races are not too far gone. Under the seal on one side you will see two gaps in the inner edges of the races. Line them up and you can pop the bearings out and replace them. Its a lot of fun putting them back together!

Best external bb <£20?

i find it easier to knock the plastic "top hat" seal out from the inside rather than prize it off (only time I tried prizing it off I snapped it).

you might be able to get away with cleaning out the bearings and regreasing them if they are just gritty, but there's no play.

Mine are going strong after a re-grease.

edit; from a near identical thread a few hours ago-

http://www.mountainbikerides.co.uk/fettling/hollowtech2bb.htm

If you need bearings…

http://cgi.ebay.co.uk/6805-2RS-61805-2RS-RUBBER-SEALED-BEARING-25x37x7mm_W0QQitemZ310125448454QQcmdZViewItemQQptZUK_sportsleisure_cycling_bikeparts_SR?hash=item4834eacd06&_trksid=p3286.c0.m14

Thankyou Jules.b and Munqe-chick 😀

I didn't want to try pulling the bb apart and breaking it when I've no spares at hand. But I'm glad to know that they are semi-maintainable and I'll take your advice and try poping the seals off next week when I can get to the local bike shop should i **** it up.

Did you machine a piece of ally bar or something as a punch to drift the bearing out from the back? Just there didn't look like much, if any lip to get a purch on the bearing from the back of the bracket?

I appreciate the replys anyhow! cheers 😀

I used an old socket that was a good fit to knock the bearing out. I clamped the cup betweeen two shaped bits of wood.