SM-BB72-41 Bearings
06-15-22, 01:54 AM
#1
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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?
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
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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AndrewRStewart
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06-15-22, 09:18 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
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
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.
06-28-22, 07:52 PM
#5
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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.
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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06-29-22, 08:21 AM
#6
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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)
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
https://www.vitalmtb.com/product/gui...vice-Tool,5669
07-04-22, 02:04 AM
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Race Face also makes a similar tool:
https://www.vitalmtb.com/product/gui...vice-Tool,5669
https://www.vitalmtb.com/product/gui...vice-Tool,5669
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