Grit after bottom bracket repack?
05-07-18 | 06:53 AM
#1
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Joined: Sep 2008
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From: Kansas City
Grit after bottom bracket repack?
The bottom bracket on the '87 Ironman I just picked up was smooth, but I repacked it together with all the other bearings. Now it has slight grittiness--seems obvious some dirt, dust, etc. got in there. I have a strong suspicion whatever is in the grease--an ant, piece of shop dirt, I don't know--will get pulverized pretty quick.
My question: might it be ok to do nothing? I'm not eager to overhaul the BB all over again. I hope this question does not offend the more fastidious mechanics in this forum.
My question: might it be ok to do nothing? I'm not eager to overhaul the BB all over again. I hope this question does not offend the more fastidious mechanics in this forum.
05-07-18 | 08:11 AM
#2
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Joined: Jan 2015
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I see you said it was smooth before the servicing, but I still can't help but think the BB needs new ball bearings. They may look perfect, but every time I've reused BB bearings, I've felt a slight grittyness that I never feel with new bearings.
05-07-18 | 11:18 AM
#6
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From: Los Angeles
Bikes: 78 Masi Criterium, 68 PX10, 2016 Mercian King of Mercia, Rivendell Clem Smith Jr
I'd redo, but I'm one of those fastidious mechanics you mention. 
Also, it only takes me 5 minutes or so to repack a BB, being an ex pro wrench during the loose bearing era. As an apprentice I was taught to listen to a repacked bearing for grit, and I had to do it again if there was any thing in there at all. The main trick is to lay out your bearings on a very clean rag. Don't use an old dirty one. Be very careful to keep your grease clean. Difficult if you are using grease from a tub. I personally don't change the ball bearings unless they are damaged.
Realistically, one tiny piece of grit is better than a dirty black BB bearing that hasn't been repacked, but it's really only your loss, as the BB won't last as long until it pits. If you don't ride that many miles it probably is not the end of the world. I couldn't let it be myself. Too OCD I suppose, plus long force of habit as an ex shop repair manager, etc.
Also, it only takes me 5 minutes or so to repack a BB, being an ex pro wrench during the loose bearing era. As an apprentice I was taught to listen to a repacked bearing for grit, and I had to do it again if there was any thing in there at all. The main trick is to lay out your bearings on a very clean rag. Don't use an old dirty one. Be very careful to keep your grease clean. Difficult if you are using grease from a tub. I personally don't change the ball bearings unless they are damaged.Realistically, one tiny piece of grit is better than a dirty black BB bearing that hasn't been repacked, but it's really only your loss, as the BB won't last as long until it pits. If you don't ride that many miles it probably is not the end of the world. I couldn't let it be myself. Too OCD I suppose, plus long force of habit as an ex shop repair manager, etc.
05-07-18 | 11:28 AM
#7
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From: Portland, OR
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
Any rust or debris in the seattube that might have fallen into the grease? I never thought of this before, but if there was a chance, a good way to avoid it is 1) do the repack with the bike upside down and 2) use one of those plastic cylinders (Sugino?). (I realize Salamandrine has packed far more BBs than I have.)
Ben
Ben
