Stuck Seatpost

[fausto99]

Having just spent 2 days (on and off) getting an alloy seatpost out of my 531 steel frame I'm wondering if a carbon fibe replacement would be better idea when I rebuild the bike? Can "carbon" seize inside steel seat tube? I had used a copper based anti-sieze grease with the alloy post but it clearly did not prevent problems.

p.s. would I have to get the seatpost clamp changed if I did go for a carbon f seatpin?

[pwa]

I'll be interested in the answer to that.

[Mick F]

I had used a copper based anti-sieze grease with the alloy post but it clearly did not prevent problems.

I gather you got it out? If so, how?

How often did you take it out since using copper grease?
Mine has been in my 531c frame since brand new 33years ago .............. but I take it out fairly regularly, clean it off and then re-grease. Maybe every three or four months max.

[pwa]

I had used a copper based anti-sieze grease with the alloy post but it clearly did not prevent problems.

I gather you got it out? If so, how?

How often did you take it out since using copper grease?
Mine has been in my 531c frame since brand new 33years ago .............. but I take it out fairly regularly, clean it off and then re-grease. Maybe every three or four months max.

Most people will never get into the habit of doing that. We need a solution that does not involve regularly removing the post. Different materials, different grease, whatever.

[cycleruk]

Yes a carbon post can get stuck in a steel frame, I think there has been a couple of previous forum posts concerning them.
I have just removed a carbon post from a steel frame. It was stuck but luckily, with a bit of squirming back and forth, it freed off. It still needed some force though to get it all the way out. Whether the carbon had expanded or some other reason, it was a good job I did it now.

Regarding the use of copper grease, I have been informed that the "copper" could increase the likelihood of electrolytic action between dissimilar metals.
The only places I have used "copperslip" has been on steam pipe flange gaskets / bolts and brake pads. Places where heat is involved.

[Brucey]

the other thing is that the regime required will vary hugely with the bike and its usage. A mudguardless bike ridden in winter oughtn't be left more than three or four months (tops) but a bike with mudguards that sees only occasional rain etc (and no sweat) might go a year or two between treatments without trouble.

cheers

[fausto99]

I had used a copper based anti-sieze grease with the alloy post but it clearly did not prevent problems.

I gather you got it out? If so, how?

How often did you take it out since using copper grease?
Mine has been in my 531c frame since brand new 33years ago .............. but I take it out fairly regularly, clean it off and then re-grease. Maybe every three or four months max.

Drip feed of Plusgas A over two days and an old rubber glove between the alloy seatpin and the serrated steel jaws of the vice, then rock the frame backwards and forwards. Still ruined the seatpin though.
Wow, every 3 or 4 months. Very impressive. That's more dedication to cycling than I have Once every few years, if that.
Looking at the seatpin I see no signs of white furry stuff so I think the anodisation is intact. It looks like rust on top of the alloy. I guess it's from the inside if the seat tube which has rusted and expanded inwards.

[Mick F]

Drip feed of Plusgas A over two days and an old rubber glove between the alloy seatpin and the serrated steel jaws of the vice, then rock the frame backwards and forwards. Still ruined the seatpin though.

At least you saved the frame. Well done though.

Removing, greasing, and replacing a seatpin/seatpost is a five minute job.
If all you do is loosen the clamp, rotate the post back and forth, and clamp up again, that's probably all it needs and it takes seconds.

[fausto99]

At least you saved the frame. Well done though.

There was no way on earth I would lose this frame. It was custom made to fit me in '97. It's done LEJOG and Alp D'Huez and still going strong. It just has a few dings and scuffs. I do wish others would be more careful when they chain up to it at cafe stops !

[nigelnightmare]

If the frame means that much to you then it would make sense to look after it and maintain it properly.

Either that or run it into the ground, throw it away and buy another, rinse and repeat.

Your choice.

[Abradable Chin]

I've just got a new steel frame, and I have freedom to pick the seatpin. Given that I don't really want to install a steel one (they seem to be double the weight of alternatives for some reason), and Al alloy or carbon fibre can both easily become stuck (reading stories on here, sometimes just a few months of not checking is sufficient), I might buy one that is too small in diameter, then shim it. If there is any galvanic action at the interface, there will always be another sliding interface where the galvanic action has not occured, so I'll always be able to pull out the pin. What do you reckon? I think I've even seen shims made from engineering plastics.

[Brucey]

adding a third material may increase corrosion rather than lessen it. IME undersize seatpins cause more trouble than anything else because the water gets down the gap, which won't so easily stay filled with copper ease etc because the pins moves more in use (to start with...). Shims just make everything worse, in fact. The best thing to do is to

a) make sure that you have an exact fit for the seat pin (rather than one that is a fraction undersize; if you can wiggle it when the binder is slack, maybe you need to get a larger pin...)

b) apply anti-seize

c) get in the habit of removing the seat pin on a regular basis and regreasing it.

If you ride without mudguards and/or in winter weather you may need to do c) once every couple of months.

cheers

[pete75]

If all else fails you can dissolve an aluminium seat post in a steel frame with caustic soda. You can also remove a stuck seat post fairly painlessly with a slide hammer if you've got one. Not everybody has though.

[bertgrower]

If all else fails you can dissolve an aluminium seat post in a steel frame with caustic soda. You can also remove a stuck seat post fairly painlessly with a slide hammer if you've got one. Not everybody has though.

please explain how you use a slide hammer

[fausto99]

Yes, I've used caustic soda on another frame some time ago with success. Me too: how do you set up a slide hammer for a job like this?