Stuck seatpost cost-benefit analysis
#1
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Stuck seatpost cost-benefit analysis
Hi al,
Picked up a Kona Stuff for $50 that looks to be from about 2003, with the intentions of flipping it.
The bike is in pretty good condition, except the seatpost is stuck. With some effort, the post rotates in the frame, but will not go higher or lower (something I have never experienced before).
I have never gotten to the point that i need to consider using the hacksaw trick, but this seatpost really doesn't want to come out of the frame.
My question: how much time and energy goes into extracting the post with a hacksaw blade. It sounds... awful. I am tossing up between stripping the parts (alivio group, 1 deore hydraulic disc brake, Zokes (?) triple clamps) and ditching the frame, or putting the effort in to get the bastard out and sell the compete bike (probably for $300 +/- 20% in my market, with a further 50-100 to spend).
Cheers.
Picked up a Kona Stuff for $50 that looks to be from about 2003, with the intentions of flipping it.
The bike is in pretty good condition, except the seatpost is stuck. With some effort, the post rotates in the frame, but will not go higher or lower (something I have never experienced before).
I have never gotten to the point that i need to consider using the hacksaw trick, but this seatpost really doesn't want to come out of the frame.
My question: how much time and energy goes into extracting the post with a hacksaw blade. It sounds... awful. I am tossing up between stripping the parts (alivio group, 1 deore hydraulic disc brake, Zokes (?) triple clamps) and ditching the frame, or putting the effort in to get the bastard out and sell the compete bike (probably for $300 +/- 20% in my market, with a further 50-100 to spend).
Cheers.
#2
Senior Member
If the seatpost rotates at all, then you are nowhere near needing a hacksaw. Apply a liberal dose of penetrating oil (PB Blaster, CRC Freeze Off, etc.) daily and keep working to loosen it up. Apply the penetrating oil from both ends of the seat tube (pull the BB, if you haven't already, to get access and keep it from getting soaked in penetrating oil). Ideally, clamp the post in a vise and twist the frame back and forth while pulling up with as much force as you can muster. A large pipe wrench (36" or more) can be an effective alternative if you don't have a vice (and don't plan to re-use the seatpost). Don't be afraid to put some force into it -- it's pretty amazing how much torque/tension a seat tube can handle.
#3
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Yeah that was my thinking initially. On closer inspection I can see that the old owner has tried the vise trick, there are marks on the top of the seatpost.
Is there some likely cause of the problem that lets the seatpost rotate but not go up or down? I thought that was strange.
Is there some likely cause of the problem that lets the seatpost rotate but not go up or down? I thought that was strange.
#4
if the seatpost is stuck
the bike is worthless to anyone except the 0.5% of the population who have exactly the right leg length
so i dont know how much it would be worth before or after
just that with the seatpost stuck it is worth much much less
the fifty dollars you paid is probably about right
regardless of what other work has been done to the bike
the bike is worthless to anyone except the 0.5% of the population who have exactly the right leg length
so i dont know how much it would be worth before or after
just that with the seatpost stuck it is worth much much less
the fifty dollars you paid is probably about right
regardless of what other work has been done to the bike
#5
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A remote possibility but is the seatpost the type that uses an expander wedge (like a quill stem) to tighten in place? If so the wedge may be stuck and could be knocked loose by backing out the bolt and hitting it on the head with a hammer like you do to loosen a quill stem.
#6
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Given that the seatpost is already marked up, I'd be inclined to just cut it. It's going to be quicker to hacksaw it, than it is to keep putting penetrating oil on it and waiting.
Hacksawing it out might take 15 minutes.
If you can save the seatpost, it would obviously be cheaper, so it's a question of time versus money.
Hacksawing it out might take 15 minutes.
If you can save the seatpost, it would obviously be cheaper, so it's a question of time versus money.
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#7
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Any chance that a water bottle cage bolt is pushing into the seat post? Only thing that I could think of that might let a post rotate but not move vertically.
If there is room to get on it, an air impact chisel (zip gun) underneath the top of the post is supposed to work well. You can even drill a hole crosswise through the seat post, put a bar in the hole and then use the airgun against the bar.
If there is room to get on it, an air impact chisel (zip gun) underneath the top of the post is supposed to work well. You can even drill a hole crosswise through the seat post, put a bar in the hole and then use the airgun against the bar.
#8
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Given that the seatpost is already marked up, I'd be inclined to just cut it. It's going to be quicker to hacksaw it, than it is to keep putting penetrating oil on it and waiting.
Hacksawing it out might take 15 minutes.
If you can save the seatpost, it would obviously be cheaper, so it's a question of time versus money.
Hacksawing it out might take 15 minutes.
If you can save the seatpost, it would obviously be cheaper, so it's a question of time versus money.
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If it rotates, it will come out provided there isn't any oddness like a water bottle bolt sticking into it. You just need more strength. Strip the frame so there is no fork, no rear wheel and maybe remove cranks if they become an annoyance. Then have 2 big strong people pulling and twisting against the frame and seat.
I strip the frame just to make it easier to grab and move around.
I strip the frame just to make it easier to grab and move around.
#10
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Yeah that was my thinking initially. On closer inspection I can see that the old owner has tried the vise trick, there are marks on the top of the seatpost.
Is there some likely cause of the problem that lets the seatpost rotate but not go up or down? I thought that was strange.
Is there some likely cause of the problem that lets the seatpost rotate but not go up or down? I thought that was strange.
#11
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15 minutes doesn't seem out of line with the right tools. There are several "hand grips" made that will hold a blade and allow long, accurate strokes. I've used a reciprocating saw, carefully, slowly, in situations like this to do the majority of work-I then finish with a hand held blade. There are also hand "vises" that will hold the long, tough, blades designed for reciprocating saws rather than the usual hand saw blades. Good luck.
#12
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Cut slot in the seatpost with a keyhole saw, maybe another couple minutes. Cut another slot, and remove piece. If it doesn't come out then, cut another slot or two until it does.
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You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
#13
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The 'hacksaw trick' as I interpreted it is to cut the post at about 2cm above the seat tube, and use a blade down into the post to cut through the post lengthways. The post can then be kind of bent and spiralled into itself and pulled out. If we are talking about the same thing, 15 minutes sounds like a no-brainer, but I was thinking it would be more like Kopsis' suggestion (4hrs+).
#14
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No mount for drink bottle on the seat tube, and it's not a quill seat post btw.
Thanks for the help, everyone. I'll report back when I have reached a solution.
Thanks for the help, everyone. I'll report back when I have reached a solution.
#15
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Bench vise. Slide hammer. Air chisel. Recip saw (sawzall). It doesn't stand a chance. But how do all these posts and stems get stuck in the first place?
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#17
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#18
Blamester
Given that the seatpost is already marked up, I'd be inclined to just cut it. It's going to be quicker to hacksaw it, than it is to keep putting penetrating oil on it and waiting.
Hacksawing it out might take 15 minutes.
If you can save the seatpost, it would obviously be cheaper, so it's a question of time versus money.
Hacksawing it out might take 15 minutes.
If you can save the seatpost, it would obviously be cheaper, so it's a question of time versus money.
in the tube.
In my experince ya gotta cut two slots to get
it out. It is a thick strong tube and the curling it around
idea doesn't work.
#20
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#21
Senior Member
+1 on the 4 hours. That was my experience last summer. But I did get that sucker out.
#22
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#24
Senior Member
I've cut a piece of a broom handle in half lengthwise, glued in a hacksaw blade overhanging the edge about the thickness of the post. Worked like a charm compared with a handheld bare blade. Don't remember exact time, but closer to 15 minutes than 4 hours anyhow.
#25
Insane Bicycle Mechanic
Strip the bike, including the cranks. Invert the frame and fill the seat tube with penetrating oil. Let it soak for a while, then grab the seatpost in a bench vice. Spin the frame around while pushing it upward- it should "unthread" itself from the seatpost.
You'll want to clean up the inside of the seattube with a straight reamer before installing a new post.
You'll want to clean up the inside of the seattube with a straight reamer before installing a new post.
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