unsticking a jammed seatpost
Discussion
TheLemming said:
OK small issue, my seat post is stuck.
I don't want to deploy brute force and ignorance as its an ally post in a carbon frame.... I'm picturing some very expensive noises if I force it.
Any ideas? Its almost in the right position so I could live with it...
Spray it with freezer spray, hoping the aluminium post will contract more than the carbon post?I don't want to deploy brute force and ignorance as its an ally post in a carbon frame.... I'm picturing some very expensive noises if I force it.
Any ideas? Its almost in the right position so I could live with it...
The seatpost stuck solid on my frame this summer, spent ages trying to use brute force wiggling the frame with the post in a vice then when that failed used heat then plusgas, ammonia etc.. Even tried cutting the seatpost with a hacksaw in a holder but was weary of accidentally cutting into the frame.
Nothing shifted the post and I was worried about damaging the frame with the amount of force needed to remove the post so I decided to leave the post in as it was seized solid and ended up reaming out the seatpost with a tool 2mm narrower than the frame and used a shim that went from 27.2 to 29.8mm then bought a 27.2mm seatpost. Took a few hours and I built up quite a sweat, had to stop every few minutes due to the amount of heat that was being generated.
If I were to do it again I would head down a proper workshop and pay them to do it with a dedicated engine block reaming tool that's used for enlarging valves and such, would probably only take a couple of minutes.
Nothing shifted the post and I was worried about damaging the frame with the amount of force needed to remove the post so I decided to leave the post in as it was seized solid and ended up reaming out the seatpost with a tool 2mm narrower than the frame and used a shim that went from 27.2 to 29.8mm then bought a 27.2mm seatpost. Took a few hours and I built up quite a sweat, had to stop every few minutes due to the amount of heat that was being generated.
If I were to do it again I would head down a proper workshop and pay them to do it with a dedicated engine block reaming tool that's used for enlarging valves and such, would probably only take a couple of minutes.
My brother got one stuck in a Cannondale a few years back. Wrote the frame off in the end.
Best I can suggest is some decent penetrating fluid, but if you squirt it round the join and it doesn't soak in, it's not doing any good. If you do get it out, make sure it's greased with something appropriate before you put it back in!
Best I can suggest is some decent penetrating fluid, but if you squirt it round the join and it doesn't soak in, it's not doing any good. If you do get it out, make sure it's greased with something appropriate before you put it back in!
You could try turning the bike upside down and squirting a load of WD40 through the drain hole in the bottom of the frame, come back in a week and try again. Just did similar to get a BB out and had to spend a bit of time cleaning WD40 of the seat post etc so it can work it's way through.....
Thanks ladies and gents,
I did drop it into a decent lbs earlier as I was in Aylesbury and they were a bit reticent about trying to shift it and hit the same "don't want to bugger the frame" point as I did.
I will try wd40 and a mole grip....
Worst case I will live with it till a carbon seat post is in the offing!
I did drop it into a decent lbs earlier as I was in Aylesbury and they were a bit reticent about trying to shift it and hit the same "don't want to bugger the frame" point as I did.
I will try wd40 and a mole grip....
Worst case I will live with it till a carbon seat post is in the offing!
I had the same a couple of months back - tried twisting and wacking with a rubber mallet but only with limited force as I was afraid of damage. After reading about various methods I thought cutting it out was the best option.
Luckily there were slits in the frame to front and rear of the post so the after cutting about 1.5 inches above the frame I could cut straight down with a normal hacksaw for the first couple of inches. Then I used the blade only to cut a vertical line down the inside of the post - creating a "track" for the blade was the worst bit - once the blade was sat in a recess I guess it probably took an hour or so to cut through. Obviously be very careful as you get near to cutting through the post. I gripped the post with pliers and compressed as the cut gave a couple of mm gap, this movement was enough to allow the post to slowly work free and it came out fairly quickly after that.
I didn't think it was as bad as I had expected, I'd allow yourself a couple of hours over 2-3 nights.
Luckily there were slits in the frame to front and rear of the post so the after cutting about 1.5 inches above the frame I could cut straight down with a normal hacksaw for the first couple of inches. Then I used the blade only to cut a vertical line down the inside of the post - creating a "track" for the blade was the worst bit - once the blade was sat in a recess I guess it probably took an hour or so to cut through. Obviously be very careful as you get near to cutting through the post. I gripped the post with pliers and compressed as the cut gave a couple of mm gap, this movement was enough to allow the post to slowly work free and it came out fairly quickly after that.
I didn't think it was as bad as I had expected, I'd allow yourself a couple of hours over 2-3 nights.
Spraying WD40 in there is the worst thing you can do as it will make the carbon expand and tighten around the post. As duff suggested your best bet will be to just cut the post off and then hacksaw down the hole.
When you fit your replacement post use some carbon paste to prevent this from happening again!
When you fit your replacement post use some carbon paste to prevent this from happening again!
What is it that causes carbon posts to stick in frames? Is it something to do with the laquer? I would've thought carbon would be pretty inert.
I had an aluminium post get stuck in a magnesium alloy frame once. Tried all the usual methods without much luck. In the end I just chopped it and pushed it down in the frame, theres still 4" or so down there somewhere. At some point I'll have a go at it with a dremel or something if I ever end up with a load of time on my hands.
I had an aluminium post get stuck in a magnesium alloy frame once. Tried all the usual methods without much luck. In the end I just chopped it and pushed it down in the frame, theres still 4" or so down there somewhere. At some point I'll have a go at it with a dremel or something if I ever end up with a load of time on my hands.
Barchettaman said:
Put the bike, upside down, in a vice, and turn the frame with the post in the vice.
I use an old rear hub between the chainstays to reduce the stress on the frame.
Works most of the time for me.
Works most of the time - Foo me - how often does it happen? Time for some prevention lessons!I use an old rear hub between the chainstays to reduce the stress on the frame.
Works most of the time for me.
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