T-Bob Posted October 25, 2013 Share Despite checking on regularly on my seat post as part of the maintenance on my Giant TCR I went to adjust it yesterday after track and it's not budging. I've googled away but wondering if anyone had some real luck shifting carbon on carbon? Most forum advice out there seem along the lines of don't use anything / do use everything! because you may or may not melt, break, kill the frame. Would really prefer not to have to break it out. Link to comment Share on other sites More sharing options...
Wil6 Posted October 25, 2013 Share There was a thread a while ago about this. https://community.bikehub.co.za/topic/126742-stuck-carbon-seatpost-in-carbon-frame/ Link to comment Share on other sites More sharing options...
droo Posted October 25, 2013 Share Do a forum search, there's plenty of advice on what to do. Then when you've tried it all and it's still stuck, saw it out with a hacksaw blade. Sorry for your loss... it's a proper pain in the bum. Link to comment Share on other sites More sharing options...
Wil6 Posted October 25, 2013 Share I bought a carbon frame for cheap the other day because the aluminum seatpost was stuck. The owner of the frame tried everything. They even went as far as to try and pull it out with a hydraulic puller. All that did was it broke the seatpost flush of with the frame and all hope was lost. 5 hours of sawing 2 vertical lines trough the seatpost until I reached the carbon frame, a screwdriver and hammer and a bit of luck and it was out. Link to comment Share on other sites More sharing options...
Mr Giant Posted October 25, 2013 Share Had a similar issue, I literally stuck the head of the seat post in a vice grip and gently twisted left to right a few times and walla...it was free to move...try it? Otherwise there is a carbon place by Rosettenville that sorts out little issues like this... Link to comment Share on other sites More sharing options...
Wil6 Posted October 25, 2013 Share Here are some before and after pics Link to comment Share on other sites More sharing options...
Mr Giant Posted October 25, 2013 Share Wemmer Pan to be exact, they repair anything carbon and fibre glass related... Link to comment Share on other sites More sharing options...
T-Bob Posted October 25, 2013 Share Cheers for the advice... time to get back to it and see if I can make inroads before resorting to 'savage removal' and trying to buy a new TCR post. Link to comment Share on other sites More sharing options...
Wil6 Posted October 25, 2013 Share Cheers for the advice... time to get back to it and see if I can make inroads before resorting to 'savage removal' and trying to buy a new TCR post.The unfortunate thing is, if its really stuck there is no way you are going to get it out without resorting to savage removal. But I hope you get it out without loosing your seatpost. Link to comment Share on other sites More sharing options...
Mr Giant Posted October 25, 2013 Share Macrabi is the name of the company! T-Bob 1 Link to comment Share on other sites More sharing options...
Li Mu Bai Posted October 25, 2013 Share Carbon on carbon may be an issue. you may end up cracking the frame as that bit of carbon under the seatpost clamp is split and usually quite thin. better to cut out the seatpost and replace, than damage your frame. I have had a carbon seatpost properly stuck in an aluminium frame about 15cm in.I had to use kettle after kettle of boiling water to get it out. pouring the hot water over the affected area allowed the seat post to shift about 2-4mm at a time before cooling and re-sticking. (aluminium expands differently to carbon). it took over 5 hours, but i finally got it out with no damage to either frame or seatpost. General rule, dont EVER use grease on your seat post, it forms wax after a while and then acts like glue. Use carbon assembly paste and regularily service this to keep the two apart. Edited October 25, 2013 by Li Mu Bai Link to comment Share on other sites More sharing options...
Rider3000 Posted October 25, 2013 Share Does this happen a lot? and if so whats the prevention ...to take it out alot and maybe add very little grease maybe?? havent happened to me "yet" so ill try to prevent it. Link to comment Share on other sites More sharing options...
T-Bob Posted October 25, 2013 Share This seems logical but I'm struggling to visualise this in practice: ------------------------------------------------------Then I stepped back to my engineering thinking (for last 20 years I design and build special prototype machinery). First I checked on the heating / cooling options and found that the thermal expansion of carbon epoxy composites is only 0.000001/F which makes it one of the materials with absolutely best thermal stability - forget about heating or cooling carbon - it will not help and may only damage the frame.Then I started to analyze the physics of pulling one composite tube out of another. I was sure it was not glued together, as the frame is old enough to be perfectly cured and the tube was there only for a few weeks. It was only held there by friction. It was not inserted with a lot of force so it must have created some mechanism that locks the pieces together. My further conclusion was that if you pull on the frame trying to pull out the post you are causing the seat tube to elongate, which in turn reduces its diameter and causes even tighter clamping on the post. The more force you apply pulling on the seat tube, the It is exactly what happens when you put one piece of plastic tubing in another piece of tubing and then try to pull it out. [like a Chinese finger puzzle -- John Allen]The best way to do it is not pulling on the outer tubing, but pushing the big tubing off the small tubing, just pressing on the edge of the outer tube while pulling on the end of the inner tube. Now I knew I would be able to do it. I only needed some way to apply reasonably large force just on the top edge of the seat tube. I took two aluminum plates that just fitted nicely between the seat rail clamp plate and the top of the seat tube (one plate on one side of the seat post and the other on the opposite), with the seat rail clamp screws extended by a few turns. Then I gently turned the rail clamp screws in and the seat post just came out without any struggle :) I did not apply any more force then, just slight finger pressure on the Allen key while turning the screws. I am sure that a similar method may be used on metal frames and seat posts or any combination of the material. You just need the right length of spacer blocks or some kind of screw attachment to do the pushing off the seat tube from the seat post.----------------------------------------------- bikebefok 1 Link to comment Share on other sites More sharing options...
droo Posted October 25, 2013 Share Makes sense. Let us know if it works, I'd like to be proved wrong on this one. Link to comment Share on other sites More sharing options...
T-Bob Posted October 28, 2013 Share Makes sense. Let us know if it works, I'd like to be proved wrong on this one. To be honest I couldn't actually work out the best way to do it so that is plan F. Currently using WD-40 and a cut off piece of metal tape measure (thinest thing I could find) to silde down between the post and frame to try to dislodge what ever it is that is causing the issue. Seems to able to move all the way around to depth of about 10cm but the post still isn't moving despite small amouts of wd-40 starting to come out the bottom of the BB drain holes. New posts are up at R1,900 so not keen to have to spend a 5th of a new frame quite yet. Penetrating oil is up next... Edited October 28, 2013 by hellocolour Link to comment Share on other sites More sharing options...
SURFER Posted October 30, 2013 Share Is this a carbon seat post stuck in carbon frame? Link to comment Share on other sites More sharing options...
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