SM-BB72-41 Bearings
#1
Member
Thread Starter
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?
#2
Senior Member
Join Date: Feb 2012
Location: Rochester, NY
Posts: 18,063
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4197 Post(s)
Liked 3,849 Times
in
2,300 Posts
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
__________________
AndrewRStewart
AndrewRStewart
#3
Member
Thread Starter
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
#5
Senior Member
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.
Likes For Dave Mayer:
#6
Senior Member
There is a tool ro remove and replace the bearings, but it is expensive Outboard BB Bearing Puller/Press (enduroforkseals.com)
#7
Senior Member
Join Date: Jun 2002
Location: Montreal, Quebec
Posts: 5,923
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1818 Post(s)
Liked 1,693 Times
in
974 Posts
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
#8
Droid on a mission
Join Date: May 2018
Location: Palm Coast, FL
Posts: 1,005
Bikes: Diamondback Wildwood Classic
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 317 Post(s)
Liked 280 Times
in
195 Posts
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
__________________
JoeTBM (The Bike Man) - I'm a black & white type of guy, the only gray in my life is the hair on my head
www.TheBikeMenOfFlaglerCounty.com
JoeTBM (The Bike Man) - I'm a black & white type of guy, the only gray in my life is the hair on my head
www.TheBikeMenOfFlaglerCounty.com