F***** Seat Post
- Thread starter J4CKO
- Start date
Page may contain affiliate links. Please see terms for details.
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
Mine was greased. Although admittedly, not regularly.
Not having a fluted stem, to let salty water run down between the stem and seat tube, would probably help.
Not having a fluted stem, to let salty water run down between the stem and seat tube, would probably help.
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
Erm, no. But my ride to work includes a stretch of trunk road. On a damp day in winter, I arrive at work splattered in salty water - I can taste it on my lips, and when I wash my hair, the water comes out grey.
(Mini-rant: I shouldn't have to put up with being sprayed with corrosive liquid just to get to work. The fact that I do is a consequence of a car-based culture. Would most car drivers put up with the same treatment? Don't I have a right to move freely around my own country without the indignity of being sprayed with road muck every day? And that's without considering the threat to my own safety... etc. etc..... and breathe...)
Nowadays, I ride the flying banana in winter (less to go wrong, and less to care about if it does). But this stuck seatpost is the last consequence to be fixed of using my Galaxy for the job.
(Mini-rant: I shouldn't have to put up with being sprayed with corrosive liquid just to get to work. The fact that I do is a consequence of a car-based culture. Would most car drivers put up with the same treatment? Don't I have a right to move freely around my own country without the indignity of being sprayed with road muck every day? And that's without considering the threat to my own safety... etc. etc..... and breathe...)
Nowadays, I ride the flying banana in winter (less to go wrong, and less to care about if it does). But this stuck seatpost is the last consequence to be fixed of using my Galaxy for the job.
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
OK, seatpost junkies, here's the update.
I put the bike back in the vice last night, and found that the seat post rotates a little more freely than it did. A bit more ammonia, and it rotated more freely still. This is all relative, mind you - "freely" here means that I'm heaving on the head tube and seat stays of the frame, with the seat post in the vice, and the bike rotates 30 degrees or so each way (there isn't room in my workshop to rotate it more than that).
Standing the frame the right way up and whacking the seatpin's head with a hammer will drive the seatpost into the frame - but I can't pull it out.
The problem is that I need to heave hard, upwards, on the seatpost head, while twisting at the same time.
I've tried turning the bike upside down, with the frame resting on some scrap wood, and hammering on the underside of the seatpost head, but nothing happens, probably because the force isn't applied directly along the seatpost axis.
Next steps: keep applying ammonia, in the hope that as more of the aluminium oxide is removed, it'll become free-er.
I may also try caustic soda (with great care - your warnings are heeded).
Finally, I may make up a sort of giant, engineering-grade corkscrew arrangement to allow a straight pull on the seatpin relative to the frame.
It's a 27.2mm seatpin, in a 1988 Galaxy (531 seat tube). Anyone know if it should in fact be a 27mm seatpin? If so, it could help explain the hassle I'm having...
I put the bike back in the vice last night, and found that the seat post rotates a little more freely than it did. A bit more ammonia, and it rotated more freely still. This is all relative, mind you - "freely" here means that I'm heaving on the head tube and seat stays of the frame, with the seat post in the vice, and the bike rotates 30 degrees or so each way (there isn't room in my workshop to rotate it more than that).
Standing the frame the right way up and whacking the seatpin's head with a hammer will drive the seatpost into the frame - but I can't pull it out.
The problem is that I need to heave hard, upwards, on the seatpost head, while twisting at the same time.
I've tried turning the bike upside down, with the frame resting on some scrap wood, and hammering on the underside of the seatpost head, but nothing happens, probably because the force isn't applied directly along the seatpost axis.
Next steps: keep applying ammonia, in the hope that as more of the aluminium oxide is removed, it'll become free-er.
I may also try caustic soda (with great care - your warnings are heeded).
Finally, I may make up a sort of giant, engineering-grade corkscrew arrangement to allow a straight pull on the seatpin relative to the frame.
It's a 27.2mm seatpin, in a 1988 Galaxy (531 seat tube). Anyone know if it should in fact be a 27mm seatpin? If so, it could help explain the hassle I'm having...
02GF74
Über Member
is there any of the post sticking out? Then drill/bolt/attach a large block of woodmetal so you can stand on it whilst at the same time pulling on the frame.
if you are able to turn the post, then you are 90% of the way there = don#t hammer if further in.
with the above arrangment, warm up the seat tube, say a hairdryer and then put ice cubes in water into the post and pull - the aluminium allow will contract more than the steel so should come out easier.
if you are able to turn the post, then you are 90% of the way there = don#t hammer if further in.
with the above arrangment, warm up the seat tube, say a hairdryer and then put ice cubes in water into the post and pull - the aluminium allow will contract more than the steel so should come out easier.
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
Numerous applications of ammonia solution don't seem to have got me any further forward.
(For those joining us late, I've reached the point where, with the seatpost head in the vice, vigorous heaving on the frame will rotate the seatpost, but not get it out of the frame).
I've drilled a hole through the head of the seatpost, threaded it, screwed in a length of M8 threaded rod, and tried the giant corkscrew arrangement, albeit with a rather weedy, thin-walled bit of tube. The tube collapsed rather than the seatpin shifting. The principle is sound, though, so I may re-visit that if I can get some thick-walled tube of the right inside diameter.
Shocking force might help, I thought, but hammering on the seatpost head isn't applying force exactly along the seatpost axis. What was needed, I thought, was a slide hammer. So I threaded the head of an old lump hammer onto my bit of threaded rod, screwed on a big washer and a bolt, and, with the bike upside down, thumped away with the lump hammer head sliding along the rod and banking against the nut and washer.
The seatpost may have shifted a millimetre or so. Or I might have imagined it. It's going to be a long job getting it out that way anyway.
So at lunchtime today I'm going to an old-fashioned hardware store in Stamford Bridge to see if they have any caustic soda.
I'm beginning to suspect that, whatever the state of corrosion, the seatpost is actually the wrong size, compounding the difficulty, and that I'll probably have to use the giant corkscrew or slide hammer approach even after the application of caustic soda...
Or saw it off and saw slots down inside its length with a hacksaw blade... erk.
Rest assured, if I get it out, you'll be told.
(For those joining us late, I've reached the point where, with the seatpost head in the vice, vigorous heaving on the frame will rotate the seatpost, but not get it out of the frame).
I've drilled a hole through the head of the seatpost, threaded it, screwed in a length of M8 threaded rod, and tried the giant corkscrew arrangement, albeit with a rather weedy, thin-walled bit of tube. The tube collapsed rather than the seatpin shifting. The principle is sound, though, so I may re-visit that if I can get some thick-walled tube of the right inside diameter.
Shocking force might help, I thought, but hammering on the seatpost head isn't applying force exactly along the seatpost axis. What was needed, I thought, was a slide hammer. So I threaded the head of an old lump hammer onto my bit of threaded rod, screwed on a big washer and a bolt, and, with the bike upside down, thumped away with the lump hammer head sliding along the rod and banking against the nut and washer.
The seatpost may have shifted a millimetre or so. Or I might have imagined it. It's going to be a long job getting it out that way anyway.
So at lunchtime today I'm going to an old-fashioned hardware store in Stamford Bridge to see if they have any caustic soda.
I'm beginning to suspect that, whatever the state of corrosion, the seatpost is actually the wrong size, compounding the difficulty, and that I'll probably have to use the giant corkscrew or slide hammer approach even after the application of caustic soda...
Or saw it off and saw slots down inside its length with a hacksaw blade... erk.
Rest assured, if I get it out, you'll be told.
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
I have all the rotational leverage I need with the head of the seat post in the vice and using the bike frame itself as a lever - and the seat post will rotate in the frame.
It's just that it's much harder to pull it out than to rotate it; there's nothing to pull against. Hence the corkscrew idea. It works with bottles anyway!
Perhaps I should be posting pictures...?
It's just that it's much harder to pull it out than to rotate it; there's nothing to pull against. Hence the corkscrew idea. It works with bottles anyway!
Perhaps I should be posting pictures...?
Actually, I should have said rotational leaverage and vertical pull. I had to do this on a rusted seat post on a raleigh racing bike some years back.
I drilled a hole right through the post - I think I went 4 mm, 6mm, 8mm. Then I inserted a the biggest screwdriver I could find. Then I stood over the frame, one foot on the bottom bracket and twisted and pulled like a mad man. I put much wd40 on, using the rotation to break the rust. Eventually it started to come out, just as you describe, like a corkscrew.
I didn't have a workshop or a vice or any thing else too technical - a drill, a screwdriver set, some wd40 and me mum's kitchen
I drilled a hole right through the post - I think I went 4 mm, 6mm, 8mm. Then I inserted a the biggest screwdriver I could find. Then I stood over the frame, one foot on the bottom bracket and twisted and pulled like a mad man. I put much wd40 on, using the rotation to break the rust. Eventually it started to come out, just as you describe, like a corkscrew.
I didn't have a workshop or a vice or any thing else too technical - a drill, a screwdriver set, some wd40 and me mum's kitchen
Brahan
Über Member
- Location
- West Sussex
This is what I tried. Drilled a hole, inserted screw driver and attached my car jack to it. I rested it on the top tube but after a few turns it still didn't budge. I got worried about how much stress it could take so didn't push too hard. Removed eventually by lots of force and a vice. Good luck.
Ladies and Gentlemen of the class of '97,
Grease your seatpost. If I could offer you only one tip for the future, greasing your seatpost would be it. The long term
benefits of greasing your seatpost have been proved by scientists, whereas the rest of my advice has no basis or
reliable then my own meandering experience. I will dispense this advice....now.
Enjoy the power and beauty of your youth. Oh, nevermind, you won't understand the power and
beauty of your youth until they've faded, but trust me in 20 years, you'll look back at photos of
yourself and recall in a way you can't grasp now how much possibility lay before you and how fabulous
you really looked. You are not as fat as you imagine.
Don't worry about the future, or worry, but know that worrying is as effective as trying to solve an algebra
equation by chewing bubblegum.
The real troubles in your life are apt to be things that never crossed your worried mind: the kind that blindsides
you at 4pm on some idle Tuesday. Do one thing every day that scares you.
.......
But trust me on the seatpost grease.
Grease your seatpost. If I could offer you only one tip for the future, greasing your seatpost would be it. The long term
benefits of greasing your seatpost have been proved by scientists, whereas the rest of my advice has no basis or
reliable then my own meandering experience. I will dispense this advice....now.
Enjoy the power and beauty of your youth. Oh, nevermind, you won't understand the power and
beauty of your youth until they've faded, but trust me in 20 years, you'll look back at photos of
yourself and recall in a way you can't grasp now how much possibility lay before you and how fabulous
you really looked. You are not as fat as you imagine.
Don't worry about the future, or worry, but know that worrying is as effective as trying to solve an algebra
equation by chewing bubblegum.
The real troubles in your life are apt to be things that never crossed your worried mind: the kind that blindsides
you at 4pm on some idle Tuesday. Do one thing every day that scares you.
.......
But trust me on the seatpost grease.
Amanda P
Legendary Member
- Location
- York. Well, York-ish...
Now where have I heard that speech before...?
This seatpost was greased. How much worse would it be if I hadn't greased it?
Anyway - update. I got the caustic soda. I mixed a small brew of it, and after the addition of a drop of detergent, squirted some down the seatpost flutes with a syringe.
There seemed to be some reaction going on - dirty grey-brown foam appeared at the top of the flutes. It didn't make any immediate difference to the moveability of the seatpost, so I left it overnight, and this morning I squirted a little more solution down.
I will try shifting it again tonight and let you know the outcome.
(Oh, and I wear sunscreen as well).
This seatpost was greased. How much worse would it be if I hadn't greased it?
Anyway - update. I got the caustic soda. I mixed a small brew of it, and after the addition of a drop of detergent, squirted some down the seatpost flutes with a syringe.
There seemed to be some reaction going on - dirty grey-brown foam appeared at the top of the flutes. It didn't make any immediate difference to the moveability of the seatpost, so I left it overnight, and this morning I squirted a little more solution down.
I will try shifting it again tonight and let you know the outcome.
(Oh, and I wear sunscreen as well).
