adjusting a rusted-into-place seat post

A few months ago it was really snowy around here, so of course I had a lots of fun riding through/in the snow, etc. Once I was done I’d put my snow-covered unicycle in the garage, and the snow would then melt and dry off.

Unfortunately that caused parts of it to rust, most noticeably on the part of the seatpost that’s in the frame. While previously it was difficult (but possible) to adjust the seat height, now it’s pretty much impossible. I could completely take off the clamp hold it into place and continue to ride around normally. That seat post won’t budge one bit.

I’ve doused it inside and out with WD-40, I’ve tried pounding it out from beneath using another seatpost, I’ve tried smacking the seat around until I was afraid of breaking my seat, and then I smacked it some more. That sucker is stuck

So then, I have two questions:

  • Does anyone have a solution to unstick a rusted-into-place seat post? I’d like to let shorter people ride, but the seat seems to be permanently stuck at the height the I ride at (not bad for me, bad for others who would like to ride.
  • Any ideas on how to prevent rust in the future after riding in snow/rain? [/list]
  • From the sound of it, it’s so tight that clamping the post or frame in a vice isn’t going to help? You might be able to do something clever with heating it up, but I’d suggest take the clamp off and leave it off. Go for a long ride, do some trials etc. After a bit it’ll probably loosen up.

    The easiest way to prevent bad rusting is to keep your unicycle somewhere nice and warm and dry when you’re not riding it, like inside in a cupboard. It might be worth washing it after riding in the snow, cos it’ll get salt on it.


    Check out Sheldon Brown’s discussion;

    There is one other technique I’ve used but it only works if the seat post is Aluminum and the frame is Steel, since the two materials have different coefficients of expansion, Al being about twice that of steel. It involves liquid nitrogen, so it’s really cool.

    Thanks for the link.

    This sounds just like my problem, so I guess a trip to the hardware store is in order.

    If that doesn’t work I think I’ll ride down to the bike shop and see if they have any ideas.

    Silly me, I’ve already tried penetrating oil (WD-40).

    Hmm. Maybe the hairdryer is next.

    You should use some good penetrating oil like liquid wrench, WD40 is for smaller stuff, and doesnt dissolve the rust like liquid wrench does.

    I’ve got the same problem, for the same reasons. I’ve tried everything I could think of or find on the web. Now I’ve given up and I ride it around with no bolt in the seatpost clamp. Luckily it’s adjusted right.

    A friend of mine got one loose by soaking it in penetrating oil, then beating on the side of it with a rubber mallet. So I bought a rubber mallet, but no luck for me. I think the reason the rust has such a strong grip is that it was a 22.2 mm post jammed into a frame designed for a 22 mm post.

    Something I read: As a last resort you can sacrifice the seatpost and save the frame: saw off most of the seat post, then very carefully hacksaw through it from the inside (the long way). Then supposedly you can grab it with pliers and sort of peel it loose from within.

    Liquid Wrench, we use it all the time at my bike shop where I work for things like these

    Two bike shops, lots of penetrating oil, lots of twisting, lots of grunting, a vice, a pipe wrench, and a rubber mallet later…

    my seat post is still stuck.

    Silly me, I’ve already tried penetrating oil (WD-40).


    Although it sometimes works for the purpose, WD 40 is not primarily a penetrating oil. It is a water dispersant. That’s what the WD stands for.

    WD 40 has a largely unearned and semi-magical status as an all pupose cleaning, lubricating and mending juice. It’s mainly just to get water out of electrical circuits.

    Keep the seat post cold, and warm up the seat tube , by pouring boiling water onto a rag wrapped around it.

    The cold post will stay small, the hot tube will expand slightly.

    If you use applied traumatic percussion, use a single sharp positive blow with follow-through.

    Yeah, I had one of the bike mechanics give me that speech when I told him I used WD-40.

    I’ll try that.

    2 words…Sludge Hammer. nuff said.

    Blowtorch? Heat it up, metal expands, rust breaks… I’ve seen it done with lugnuts and disc-brake drums.

    I’ve a similar problem on my muni, the bolts on the seat clamp are frozen… But it’s the right height for me, so I leave it there :smiley: