How to check for wear in bottom bracket?
#1
Senior Member
Thread Starter
Join Date: Sep 2011
Posts: 290
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
How to check for wear in bottom bracket?
I've been running on the original external bb since I bought my bike 4 years ago. When I disconnect my chain, lean it on the frame and spin the cranks freely, there seems to be a small point in the turn where there is some slight resistance. Is it time to service this thing? If so. How exactly is this done? Do I have to buy a whole new external bb or can I replace the cups on the externals that I have now?
#2
Mechanic/Tourist
Some slight resistance in my opinion is nothing to worry about, but the bearings can be replaced. Google for the procedure.
#3
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,696
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5774 Post(s)
Liked 2,571 Times
in
1,423 Posts
I've been running on the original external bb since I bought my bike 4 years ago. When I disconnect my chain, lean it on the frame and spin the cranks freely, there seems to be a small point in the turn where there is some slight resistance. Is it time to service this thing? If so. How exactly is this done? Do I have to buy a whole new external bb or can I replace the cups on the externals that I have now?
If/when it's time to replace, you'll most likely need to replace the 2 halves of the external BB. Most of these have pressed in bearings, and don't provide for easy replacement of the bearing itself, though it's probably doable. Even so, I suspect that you'll find the cost of the bearings alone to be close to the complete BB.
One caveat for future reference. The most serious issues with this type of BB are the cups seizing in the frame because of corrosion, and a seized bearing. The seized bearing is critical because the spindle can still turn within the inner race, and riding that way will score the spindle setting up a future fracture. If you feel or hear friction, check what's happening immediately, by sliding out the cranks, and seeing that the inner race still spins smoothly.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 10-24-15 at 07:35 AM.
#4
Senior Member
Thread Starter
Join Date: Sep 2011
Posts: 290
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Okay so the slight resistance (which is mainly just a low-key fluffy noise) is negligible.
Checking it again, I also noticed that there is a slight play. If I hold the cranks on each side and try to wobble it, there is a small wobble and clicking noise with each wobble. Maybe 0.5-1mm wobble? Is this also negligible? Its not something that I notice or hear when I ride at any intensity be it standing or while sitting on the saddle.
Checking it again, I also noticed that there is a slight play. If I hold the cranks on each side and try to wobble it, there is a small wobble and clicking noise with each wobble. Maybe 0.5-1mm wobble? Is this also negligible? Its not something that I notice or hear when I ride at any intensity be it standing or while sitting on the saddle.
#5
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,696
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5774 Post(s)
Liked 2,571 Times
in
1,423 Posts
Okay so the slight resistance (which is mainly just a low-key fluffy noise) is negligible.
Checking it again, I also noticed that there is a slight play. If I hold the cranks on each side and try to wobble it, there is a small wobble and clicking noise with each wobble. Maybe 0.5-1mm wobble? Is this also negligible? Its not something that I notice or hear when I ride at any intensity be it standing or while sitting on the saddle.
Checking it again, I also noticed that there is a slight play. If I hold the cranks on each side and try to wobble it, there is a small wobble and clicking noise with each wobble. Maybe 0.5-1mm wobble? Is this also negligible? Its not something that I notice or hear when I ride at any intensity be it standing or while sitting on the saddle.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#6
Senior Member
Join Date: Sep 2009
Posts: 1,971
Bikes: Habanero Titanium Team Nuevo
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 399 Post(s)
Liked 185 Times
in
121 Posts
If this is a Shimano crank and BB Hollowtech I would just replace the BB. They are ridiculously cheap about $25 and that is whole point of why I like thread BB and external bearings, they are breeze to change and/or replace.
Thread
Thread Starter
Forum
Replies
Last Post
bryanfellenbaum
Bicycle Mechanics
6
07-08-15 04:57 PM
knighty76
Bicycle Mechanics
5
04-06-11 03:49 PM