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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.

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Old 07-29-11, 05:23 PM   #1
roburrito
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Seatpost head detached from tube - fixable?

My seatpost head is detached from the tube/post. See pictures below. Is this fixeable? Would JB weld be strong enough to hold it in place? Or is it just new seatpost time?


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Old 07-29-11, 06:22 PM   #2
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retaining compound should work i think. i think trek used to use some epoxy(not sure what product) for their older bonded aluminum frames. can also go ghetto style and nut and bolt it
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Old 07-29-11, 06:49 PM   #3
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Is that as loose of a drop in fit as it looks to be in the bottom picture?

I was thinking put the top part in the freezer overnight, bake the bottom part in the oven at about 300 degrees and put them together. If the fit is that loose, however, my idea isn't going to work. I doubt JB weld or any other bonding agent is going to work either.
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Old 07-29-11, 06:50 PM   #4
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Seatposts are cheap enough, why would you put time into a repair, or risk later failure?
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Old 07-29-11, 06:51 PM   #5
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Epoxy or one of the stronger bearing retaining versions (most are Green) of Loctite will probably work but a new seatpost is a better bet unless yours is a very unusual diameter. Even good ones aren't that expensive.

I'd be leary of the nut and bolt approach but a small bolt may be a useful strengthing aid to an epoxy repair.
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Old 07-29-11, 07:03 PM   #6
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seriously though a post like that is 25 retail. cheaper online. send that post to scrap or put in the drawer with your ratchets. the nut and bolt will hold for a bit but will probably tear out over time
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Old 07-29-11, 07:07 PM   #7
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I knew that the cheaper seatposts used insertions, but that's the first time I've seen one fall off like that.
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Old 07-29-11, 07:13 PM   #8
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I knew that the cheaper seatposts used insertions, but that's the first time I've seen one fall off like that.
I have a Bontrager zero-setback post and a Post Moderne (Trek's house brand) that have their heads press fit into the post but neither have shown any signs of looseness in tens of thousands of miles.

I believe current American Classic seatposts are also a two-piece press fit but my older one (1996) has a one piece post and lower clamp.
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Old 07-30-11, 02:23 AM   #9
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I'll buy a new seatpost and call it a day.
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Old 07-30-11, 06:10 AM   #10
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I would cross drill it and put a bolt and nut in there. If the fit is loose I might also use a shim or an epoxy such as JB Weld to help prevent it moving around. Such a repair should outlast the bicycle. Even if the repair were to fail, it would result in nothing more than a loose seat, gravity would hold it in place unless you are doing flips. I do not see that a repair using a cross bolt would present any kind of a safety hazard, and failure of the bolted repair would be highly unlikely.
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Old 07-30-11, 08:28 AM   #11
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I'll buy a new seatpost and call it a day.
good plan, ratchet jaw seatposts like that are cheap ,
get one with 2 bolts that is a stepless angle adjustment.


to save it , epoxy , and run a pin thru the tube sideways . bang one in .
thru tube and head

steel roll pin , or solid aluminum .

Last edited by fietsbob; 07-30-11 at 09:32 AM.
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Old 07-30-11, 09:24 AM   #12
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Quote:
Originally Posted by AEO View Post
I knew that the cheaper seatposts used insertions, but that's the first time I've seen one fall off like that.
I think I once made one rotate slightly trying to remove a stuck seatpost, but I may have imagined it.
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Old 07-30-11, 09:54 AM   #13
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I had one come loose a few years ago. since it was a pretty nice SR post I decided to go the JB route. it seems to work OK, but that bike does not see much use.

I agee though just get a new post, especially if the top is really as loose as it looks in pic #2
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