Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Bottom bracket bearing feels "notchy"

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Bottom bracket bearing feels "notchy"

Old 12-16-17, 03:54 PM
  #1  
Senior Member
Thread Starter
 
tyrion's Avatar
 
Join Date: Oct 2015
Location: San Diego, California
Posts: 4,077

Bikes: Velo Orange Piolet

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 2228 Post(s)
Liked 2,010 Times in 972 Posts
Bottom bracket bearing feels "notchy"

I can only feel this "notchiness" when I take the crank out and put my finger in there and rotate the bearing. Can't feel any notchiness through the crank - the crank rotates smoothly. It's not a sharp tick nor anything, doesn't make noise, just feels notchy when moving the bearing with my finger.

It's a Deore external bearing, the kind that has a sealed bearing inside the assembly that screws into the frame, and has a warning "do not remove bearing" or something.



It's a couple years old, maybe 15,000 miles. It's possible I over tightened it - a year ago had a creak down there, took everything apart, cleaned and greased, then reassembled - fixed creak - I didn't remove the bearings from the housing that screws into the frame.

Is this notchiness, normal? Caused by overtightening? Normal wear?
tyrion is offline  
Old 12-16-17, 04:06 PM
  #2  
Senior Member
 
Kontact's Avatar
 
Join Date: Apr 2011
Posts: 6,544
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 4102 Post(s)
Liked 1,291 Times in 842 Posts
Hard to say. What did you "overtighten"? The cups, or the crank tensioner? The first won't hurt the bearings, and the second is almost impossible to get too tight.

Sometimes sealed bearings can feel notchy just from the way the seals grab at low RPMs. If the cranks spin easily and don't feel odd under pedaling force, it is hard to say that there is a read problem.
Kontact is offline  
Old 12-16-17, 05:11 PM
  #3  
Senior Member
Thread Starter
 
tyrion's Avatar
 
Join Date: Oct 2015
Location: San Diego, California
Posts: 4,077

Bikes: Velo Orange Piolet

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 2228 Post(s)
Liked 2,010 Times in 972 Posts
Originally Posted by Kontact
What did you "overtighten"? The cups, or the crank tensioner?
The bearing housing assembly things - there are 2 in the above picture with the plastic sleeve between them. They just screw into the frame with the special wrench. They're so beefy looking it didn't seem possible to me to over tighten with arms and a 10 inch wrench.
tyrion is offline  
Old 12-16-17, 06:24 PM
  #4  
Senior Member
 
maddog34's Avatar
 
Join Date: Jul 2015
Location: NW Oregon
Posts: 2,972

Bikes: !982 Trek 930R Custom, Diamondback ascent with SERIOUS updates, Fuji Team Pro CF and a '09 Comencal Meta 5.5

Mentioned: 15 Post(s)
Tagged: 1 Thread(s)
Quoted: 1295 Post(s)
Liked 738 Times in 533 Posts
over-tightening the cups will not effect the bearings one bit...

the bearings are beginning to fail, and will become worse and worse quite rapidly.....

change the BB assy now.... they're cheap, $20 or so... EBay or your LBS will have one for you.
maddog34 is offline  
Old 12-16-17, 06:32 PM
  #5  
Senior Member
Thread Starter
 
tyrion's Avatar
 
Join Date: Oct 2015
Location: San Diego, California
Posts: 4,077

Bikes: Velo Orange Piolet

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 2228 Post(s)
Liked 2,010 Times in 972 Posts
Originally Posted by maddog34
over-tightening the cups will not effect the bearings one bit...
When you say "the cups" are you referring to the things that holds the bearings and screws into the frame?

Yeah I know I can get an XT BB for $20.
tyrion is offline  
Old 12-16-17, 06:33 PM
  #6  
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 17,898

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: 4123 Post(s)
Liked 3,684 Times in 2,212 Posts
One sure way to kill a bearing prematurely is to have too much preload. In these two piece cranks some designs (like Shimano's) allow for the LH arm to be drawn up too far on the axle's splined and produce too much end pressure for the bearing's capacity.


But 15,000 miles is not premature wear. It's normal for bearings to wear after many thousands of cycles of use. That you can't feel the wear with the crank arms installed just shows how much leverage the end of the cranks have over the bearings. I suspect the BB has been slowly wearing to the point you now have discovered.


This type of bearing "cup" when tightened into the frame placed very little additional preload on the bearings do only to the Bb shell, unlike the tapered square "cartridge" BB units where the bearing sits within the shell. As these are tightened the shell's threads produce an inward pressure on the BB resulting in a much tighter bearing. But the external BB's don't have this possibility. So I doubt that the "cups" tightness (in the shell) is a concern.


The simple solution is to just replace your parts as they wear to a point you can't tolerate. Andy
Andrew R Stewart is offline  
Old 12-16-17, 07:07 PM
  #7  
Senior Member
 
maddog34's Avatar
 
Join Date: Jul 2015
Location: NW Oregon
Posts: 2,972

Bikes: !982 Trek 930R Custom, Diamondback ascent with SERIOUS updates, Fuji Team Pro CF and a '09 Comencal Meta 5.5

Mentioned: 15 Post(s)
Tagged: 1 Thread(s)
Quoted: 1295 Post(s)
Liked 738 Times in 533 Posts
Originally Posted by tyrion
When you say "the cups" are you referring to the things that holds the bearings and screws into the frame?

Yeah I know I can get an XT BB for $20.
yep... that missing comma threw me a curve... the aluminum pieces pictured are referred to as Cups by many people.... i'm sure someone else has a different term for them... Bearing Retainer or Bearing Housing come to mind.

cup... nice and easy.
maddog34 is offline  
Old 12-16-17, 07:35 PM
  #8  
Senior Member
 
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702

Bikes: old clunker

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 104 Times in 82 Posts
Originally Posted by tyrion
I can only feel this "notchiness" when I take the crank out and put my finger in there and rotate the bearing. . .
Do that less, ride more.
AnkleWork is offline  
Old 12-16-17, 07:51 PM
  #9  
Senior Member
Thread Starter
 
tyrion's Avatar
 
Join Date: Oct 2015
Location: San Diego, California
Posts: 4,077

Bikes: Velo Orange Piolet

Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 2228 Post(s)
Liked 2,010 Times in 972 Posts
Originally Posted by Andrew R Stewart
The simple solution is to just replace your parts as they wear to a point you can't tolerate. Andy
Sounds like a plan, Thanks.
tyrion is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Dorian7
Bicycle Mechanics
3
10-14-14 08:23 AM
bashermax
Bicycle Mechanics
32
02-11-14 07:32 AM
veloboy971
Bicycle Mechanics
6
11-14-11 10:55 AM
reshp1
Bicycle Mechanics
6
08-12-11 03:02 PM
3DC
Bicycle Mechanics
22
03-30-10 03:28 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.