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Bottom bracket question

Old 12-03-18, 10:12 AM
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tdilf
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Bottom bracket question

While riding on wetter days, after going through muddy puddles my bottom bracket seams to grind for about 10 minutes or so and then it slowly goes back to normal while still riding. I am assuming the dirty water is going into the bottom bracket and causing this. Does this mean I have bad seals or just a crappy BB? I have a PF30. My carbon frame also has a door in the BB area for fishing wires through and I am sure that is not water tight - perhaps it is coming through there? Can I get a sealed unit for a press fit BB?
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Old 12-03-18, 10:23 AM
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Originally Posted by tdilf View Post
While riding on wetter days, after going through muddy puddles my bottom bracket seams to grind for about 10 minutes or so and then it slowly goes back to normal while still riding. I am assuming the dirty water is going into the bottom bracket and causing this. Does this mean I have bad seals or just a crappy BB? I have a PF30. My carbon frame also has a door in the BB area for fishing wires through and I am sure that is not water tight - perhaps it is coming through there? Can I get a sealed unit for a press fit BB?
It may not be actually getting into the bearings themselves, but rather on top of the seals. I have a PF30 bb that does that too and so far no long term damage has been done. I wouldn't worry about it too much until it starts costing you new bearings.
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Old 12-04-18, 05:12 AM
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Its probably not the bottom bracket. Its more likely that it is dirt from the muddy water getting on the chain and grinding on the chainring. The noise goes away as the dirt clears off the chain. If it was dirt getting into the bearings, it would not go away.
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Old 12-04-18, 02:27 PM
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If it's just puddles, I would agree that it's probably not the bottom bracket.

If it's stream crossings where the BB is submerged? Generally speaking, the more underwaterproof a BB is, the more friction you get from the seals. If you do a lot of stream crossings, get used to replacing BB's whenever the friction in the bearings (from rust or particulates) begins to escalate. That could be a couple times a year. (And yes, this is the primary reason I think ALL serious gravel bikes should have threaded BB's. Stream crossings make BB changes a lot more frequent. And threaded BBs are very easy and convenient to change.)
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Old 12-04-18, 03:02 PM
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Good until it's Not..

Press Fit BB uses Contact sealed bearings..
Buy New bearings when the old ones are contaminated.

Immersible pump spec seals on bearings are the tightest...
for obvious reasons it, the pump, operates under water.




..
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