int19

Hi all,

I have a shimano UN51 sealed cartridge BB which has had ~8 months of daily use. It has developed ~1-2mm of side to side play on the axle. Is this normal/ignorable, or is there some way I can open it and service it?

Thanks,
Richard

mikejavo

Hi Richard,

In my experience, the UN51 is a very solid BB. I've had one installed for 2 years, riding through the winter/salt/slush with no problems. My guess is that the plastic cup is no longer tightened. 1 to 2 mm of play is quite a bit, and would not be acceptable.

To answer your last question, the sealed BBs are in no way serviceable.

JunkYardBike

+1 Try tightening the NDS (non drive side) cup, but just make it snug. If it is indeed plastic, if you overtighten, it can easily crack. If you can remove the crank and regrease the sleeve (or even back it out enough to apply some grease) that should help keep it tight. If it's aluminum or steel, you can even use some blue (medium strength) loctite to keep it in there.

You'll need something like the Parktool BBT-2 (being replaced by BBT-22 says the website):

int19

Sadly, both cups are threaded securely into the shell. I checked that as it appeared to be the only adjustment I could make.

So the prognosis is that the BB is a goner then?

poopncow

fortunately, they are relatively inexpensive