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SM-BB72-41 Bearings

Old 06-15-22, 01:54 AM
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Wabeery
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SM-BB72-41 Bearings

My pressfit bb72-41 is starting to suck (cranks are pushing through mud) and needs a service. Can i just clean out the bearings, regrease, and reinstall? Or do I need a replacement BB? Further question: if I they need replacing can I just replacing the bearings rather than the whole system?
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Old 06-15-22, 07:59 AM
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Generally these BBs are considered to be non serviceable. If one can get access to the bearings' seals one could pry off the outer seals and clean/lube the interior. Know that this service will only address the condition of the lube and not any actual bearing surface issues (like wear, rust or pitting). But once clean and with the seal still off an experienced hand could spin the bearing and thus get some indication to the condition.

If one could remove the bearings from their "cups" then just the bearings could be replaced. However Shimano doesn't design these units to be able to do this easily.

Most will just replace the entire BB. Andy
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Old 06-15-22, 09:18 AM
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Originally Posted by Andrew R Stewart View Post
Generally these BBs are considered to be non serviceable. If one can get access to the bearings' seals one could pry off the outer seals and clean/lube the interior. Know that this service will only address the condition of the lube and not any actual bearing surface issues (like wear, rust or pitting). But once clean and with the seal still off an experienced hand could spin the bearing and thus get some indication to the condition.

If one could remove the bearings from their "cups" then just the bearings could be replaced. However Shimano doesn't design these units to be able to do this easily.

Most will just replace the entire BB. Andy
Thank you Andy, I’ll avoid any hassle with ‘servicing’ and grab some new ones instead. Appreciate the reply.
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Old 06-15-22, 10:31 AM
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I once worked on mine for hours and got a few more months out if. So yeah.
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Old 06-28-22, 07:52 PM
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I just did a cleaning of a BB72-41. A customer had thrown it away; it didn't feel too crunchy, but water had definitely got inside the frame and left a grimy mess.

It only took a few minutes to crack the seals with a small flat-blade screwdriver in order to get to the bearings. They were filled with a vile black good, which I proceeded to clean out with mineral spirits. I then let dry out and regreased. Seems now be good as new: smooth and no bearing play.
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Old 06-29-22, 08:21 AM
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There is a tool ro remove and replace the bearings, but it is expensive Outboard BB Bearing Puller/Press (enduroforkseals.com)
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Old 07-03-22, 08:58 AM
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Race Face also makes a similar tool:
https://www.vitalmtb.com/product/gui...vice-Tool,5669
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Old 07-04-22, 02:04 AM
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Originally Posted by alcjphil View Post
Race Face also makes a similar tool:
https://www.vitalmtb.com/product/gui...vice-Tool,5669
But this listing says discontinued
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