Seat post won't slide down!

Ok, I recently had problems getting my seat post out from my Coker. I ended up having to use some wd40 and pulling it out. Now there are some scratches on the post and the inside of the frame. I used some sand paper to smooth out the post a little, especially around the bottom edges. Now when I am trying to put it back in, the post just won’t slide all the way down. It just stops half way and I can’t really seem to force it any further. How can I get it down there? :thinking: . Also should I lubricate the post and the inside of the frame, and is there any way to make sure it will come out clean next time?
Thanks guys

Don’t lubricate it!

Have you cut your seatpost? Sometimes when you cut it, the metal expands (the diameter increases a bit). This happens especially with pipecutters!

Probably inside your seattube (Unicycle seat tube), there are small scratches… You should take some kind of tube, and try to sandpaper it… Just a bit… With a light sandpaper…

After that, if it does not comes in, you could try to sand the seatpost, but be careful, take just a BIT, you your seatpost can rotate after that.

You can use WD40 or this stuff, but the seatpost is made to fit PERFECTLY the unicycle, so it SHOULD NOT be used… It can also helps to have a rotating tube… Especially if you’re using a T7 or doing unispins

Hey pedro thanks for the quick reply. Yes I did saw off the post. I’ll try sandpapering the inside a little to see if that works…

Just use a light sand paper, and sand just to have it really polished inside… Don’t take much metal!.. You can check with you fingers if it’s really polished :wink:

Also, if you can put some air inside (compressor) after to clean it’s good to… I used my mom hair dryier thing :stuck_out_tongue:

You should always lube a seatpost, and especially if the frame/post materials are a combination of steel/aluminum. Use grease, the same as putting pedals on. If the fit is as tight as it should be, then you will not have any problem with the post slipping, and it will prevent corrosion/galvanic action that can seize your post in place. If it fits correctly, and you lubed it you should never have to twist it while putting it in, or taking it out.

I have had to put a torch on some stubborn posts that were stuck in place because the owner cleaned the grease out of the seat tube. It is a lot of work that gets the post out but ruins the paint on the frame, and generally requires a new post.

After working in bike shops for 10 years I can say that there is no good reason not to grease a seatpost, and plenty of good reasons why you should.

If you have a frame/post combination that is steel/aluminum it is likely that the reason it was hard to get out was galvanic action. When you removed the post you left the residue in the seat tube, and it is blocking your post from going in. You can either bring it to a shop and have them ream the tube to the correct diameter, or carefully sand/file the inside of hte seat tube until the post goes in easily. Without seeing it I can’t say for sure that this is what’s going on, but I have seen many similar problems.

I WOULD NEVER grease my seatpost again… Maybe for bikes it’s good, but for unis, no way… I did that in my first street uni and had terrible results… All 180s on wheel, 540s and even 720 attemps were terrible… I always had to put the seat again on the right position…

Now, I can’t imagine with 720s and harder flip tricks how it would be, but not good I think! Better riders than me, like Adrien and Loic, have to re-adjust their seatposts each 900 attempt… with grease would be crazy…

Even with 2 bolted clamps I had the same problem…

I also know that with T7s, especially while mounting, the seats usually turns… Probably there’s less force than in street and flat riding, but maybe grease can create a problem too…

I only had a stucked seatpost when I used a pipe cutter on my frist KH seatpost at UNICON, but now I just use a saw and after round the edges with a fill, and all seatposts fits perfectly!

You make a very good point about the torque involved with tricks on the uni. It makes me think two things immediately:

  1. If you are doing tricks that will put excessive torque on the seat you are going to need a special set up that may include no grease on the post. If the frame and post material are the same then you won’t have galvanic action, and you could be a bit safer without grease.
  2. A commuter uni is more likely going to be in inclement weather, and as such will be more prone to a seized post due to galvanic action. Also, a commuter is most likely not going to be put through the same kind of torqe that a street/freestyle uni will.

From the description of the problem I still think that corrosion is the culprit, and that a thin film of grease would have prevented the problem. If you really want to make sure that the post won’t spin you could use a heavy axle grease. That stuff is so sticky it would probably help the post stay put.

It seems like with most things there is no single answer that works for every situation.

Is heavy axle grease a more consistent? More rigid?.. I may try that on my 26… If works would be great… I will ask my dad for some and I post the results :wink:

what if you use something like linseed oil?