Metal Shavings in Bottom Bracket?
02-01-08, 09:54 AM
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Metal Shavings in Bottom Bracket?
My LBS is doing a complete check on my 1 year old Seven ID8.
They have alerted me that they have found a SIGNIFICANT amount of what appears to be metal shavings located inside the bottom bracket cups.
Any idea what this could be from????
They have alerted me that they have found a SIGNIFICANT amount of what appears to be metal shavings located inside the bottom bracket cups.
Any idea what this could be from????
02-01-08, 10:02 AM
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Could be remnants from tappng the BB shell during construction, or from reaming/facing the BB threads prior to assembly.
Oh wait, inside the cups themselves, not the shell? No clue. Maybe the BB races cannibalized themselves? You think you would hear/feel something amiss if that was happening.
Oh wait, inside the cups themselves, not the shell? No clue. Maybe the BB races cannibalized themselves? You think you would hear/feel something amiss if that was happening.
02-01-08, 12:19 PM
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Not without more info. What type of frame? What frame material? What type of frame construction? What type of BB is installed? Are the shavings metal? What type of metal?
02-02-08, 12:54 PM
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If the bike is one year old, then it probably has external bearings so shavings "inside" them would be in the hanger tube - probably from machining the tube. If your LBS has the BB apart to the extent that they can see inside the tube, then they can evaluate the condition of the bearings.
Did they recommend any course of action based on the shavings?
Did they recommend any course of action based on the shavings?
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02-02-08, 04:33 PM
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when I opened up my (late 70's?) motobecane's BB I also found a nice pile of shavings,...but could find absolutely NO damaged bearings, cups, cones, or anything, in fact the entire tange BB was in almost perfect shape and these were BIG chips, definately not the usual powdered or crumbled mess you find in a vintage BB, more like chamfering bit shavings (perfect little 1/8" curls, all with the same "v"cross section
I examined the entire rest of the frame, and again could find no evidence of where these shavings came from.
I figured it was from the original machining/tapping, and they just didn't flush out the chips before assembling the bike, or they were stuck (too much cutting fluid) far up in the tubes, and took 37 years to work their way down to the BB.
strange but true.
I examined the entire rest of the frame, and again could find no evidence of where these shavings came from.
I figured it was from the original machining/tapping, and they just didn't flush out the chips before assembling the bike, or they were stuck (too much cutting fluid) far up in the tubes, and took 37 years to work their way down to the BB.
strange but true.
Last edited by reckon; 02-02-08 at 04:38 PM.
02-02-08, 06:44 PM
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That your LBS would tell you of this and offer neither reason nor solution is alarming, especially in lieu of possible warranty implications. "Appears to be metal shavings" seems to be an easily testable hypothesis on their part. Something smells here.
