Stuck Carbon Seatpost in Carbon Frame

[Sani]

If you want to try a slide hammer puller first - I have one - pm me - it will probably mean cutting the seatpost, but I guess by now you are beyond caring about that.

 

I also have a couple of strap wrenches we could try to twist it out with - also worth a shot.

I also think the slide hammer puller would be the answer ,

[Oltremo]

I fixed mine a few weeks ago, with Q20 lube. Loosened clamp, sprayed on a bit, left it over night, next morning used screw driver to pry open lip slightly, sprayed little more. 12 hours later, went back, twisted seat from side to side, eventaully got it loose.

[YUMEYA]

Ok, so we options on how to fix it but how do we prevent this???

 

fresh carbon assembly grease on your seat post after washing your bike or riding in wet conditions.

[rad006]

why not... a trained person that render a service for which he is paid, no? If a person come to me with a cold, I dont say wtf why do you come with something that I cant do anything with... I help give relief and send them on their way...

Just a thought

 

JB is more than my LBS and he was just pulling my leg with a joke as always...

 

So update, it turns out the post is actually an aluminium with carbon wrap unit.

Interestingly the carbon frame has an aluminum tube inside it for strength so the bond is as strong as hell..

We tried all forms of twisting and pulling no luck whatsoever...

So we cut it but couldn't cut it deep enough so JB is getting a special saw for us to try tomorrow....

 

I will continue the outcome tomorrow...

[Tumbleweed]

why not... a trained person that render a service for which he is paid, no? If a person come to me with a cold, I dont say wtf why do you come with something that I cant do anything with... I help give relief and send them on their way...

Just a thought

 

A valid thought.

[Johan Bornman]

why not... a trained person that render a service for which he is paid, no? If a person come to me with a cold, I dont say wtf why do you come with something that I cant do anything with... I help give relief and send them on their way...

Just a thought

What a ridiculous thought. Besides the fact that it was a little inside joke between RAD and I, I have the freedom to choose exactly what bikes I want to work on and which not. If I don't like blue bikes, tough for anyone with a blue bike. If I don't work on kiddies bikes, I don't. What compels me to do so?

 

And as for that vexatious little yapping dingle berry-infested dog in agreement with you, he utters a little yelp at every challenge I receive on this forum. He seems to get kicks out of it.

[BogusOne]

What a ridiculous thought. Besides the fact that it was a little inside joke between RAD and I, I have the freedom to choose exactly what bikes I want to work on and which not. If I don't like blue bikes, tough for anyone with a blue bike. If I don't work on kiddies bikes, I don't. What compels me to do so?

 

And as for that vexatious little yapping dingle berry-infested dog in agreement with you, he utters a little yelp at every challenge I receive on this forum. He seems to get kicks out of it.

 

MOER MEKAAR fred here please

 

https://community.bikehub.co.za/topic/126618-friday-fight-club%e2%80%a6/

[Eric Rautenbach]

Take a hairdryer and heat the external tube up while pouring ice water down the inside of the seat post. Then take a rubber hammer and moer the post down into the tube.

[Johan Bornman]

OK, for those of you interested in the problem and its solution. The problem is solved but won't go away.

 

The seatpost in question was a carbon-wrapped aluminium post inserted into a carbon-wrapped seat tube. In other words, the seat tube was naked aluminium inside. Big problem this.

 

 

As you can see from the photo, the submerged piece of post was quite long, compounding the problem. The carbon wrap stayed behind once the post was removed and itself was stuck.

 

The aluminium on the post corroded underneath the carbon wrap, causing the post's Outside Diameteer (OD) to increase. Further, the seat tube corroded too, causing the tube's ID to shrink. This effectively throttles the seatpost in the bike, forming a very, very strong mechanical connection. Not a chemical bond, but mechanical constriction.

 

To remove a stuck seatpost, chemistry is not the answer. Whatever chemical you intend getting in there - coke, caustic soda, whatever, cannot penetrate. The area of attack will only be a one-molecule thick ridge. Look at the post and you'll see why - the white on the aluminium indicates that the entire length of the post was corroded. It has to be a mechanical approach. In this case we had to cut the post off 40mm above the seatpost clamp and then saw through the side of the post.

 

Since the post was in deep, a standard hacksaw blade was too flimsy. It flexed too much over that length. I had to purchase a 32mm blade and grind it down to 26mm to fit inside the post.

 

Job done.

 

How to prevent it? You can't. Regularly remove and clean the post and wipe it clean.

Edited June 17, 2013 by Johan Bornman

[rad006]

Wow is that what it looked like thanks JB...

I'll arrange to fetch it asap.

[stratus5]

OK, for those of you interested in the problem and its solution. The problem is solved but won't go away.

 

The seatpost in question was a carbon-wrapped aluminium post inserted into a carbon-wrapped seat tube. In other words, the seat tube was naked aluminium inside. Big problem this.

 

 

As you can see from the photo, the submerged piece of post was quite long, compounding the problem. The carbon wrap stayed behind once the post was removed and itself was stuck.

 

The aluminium on the post corroded underneath the carbon wrap, causing the post's Outside Diameteer (OD) to increase. Further, the seat tube corroded to, causing the tube's ID to shrink. This effectively throttles the seatpost in the bike, forming a very, very strong mechanical connection. Not a chemical bond, but mechanical constriction.

 

To remove a stuck seatpost, chemistry is not the answer. Whatever chemical you intend getting in there - coke, caustic soda, whatever, cannot penetrate. The area of attack will only be a one-molecule thick ridge. Look at the post and you'll see why - the white on the aluminium indicates that the entire length of the post was corroded. It has to be a mechanical approach. In this case we had to cut the post off 40mm above the seatpost clamp and then saw through the side of the post.

 

Since the post was in deep, a standard hacksaw blade was too flimsy. It flexed too much over that length. I had to purchase a 32mm blade and grind it down to 26mm to fit inside the post.

 

Job done.

 

How to prevent it? You can't. Regularly remove and clean the post and wipe it clean.

 

Well done. I had to tear mine out in little pieces. Carbon seat tube, no aluminium. Bike was aluminium though. Corroded solid.

 

Could you get a machine shop to drill or mill it out?

[Guest Latent Blue]

Eish... so ill have to check on my barbon laced alu seat post too...

[nolipoli]

Carbon and aluminium actually don't share space well together, and this corrosion of the aluminium is frequently encountered, and is an issue that extends all the way up to the aerospace industry.

 

The solution - titanium. Although I also wonder if there would be an improvement if the aluminium was anodised first...

[King_Crispy]

Wow is that what it looked like thanks JB...

I'll arrange to fetch it asap.

With a BIG wad of cash, and a box of smarties

Edited June 17, 2013 by King_Crispy

[Christie]

Carbon and aluminium actually don't share space well together, and this corrosion of the aluminium is frequently encountered, and is an issue that extends all the way up to the aerospace industry.

 

The solution - titanium. Although I also wonder if there would be an improvement if the aluminium was anodised first...

Anodize would be more resistant to galvanic corrosion, but the carbon wont bond well on it. Dont use alu with carbon where water or sweat can get trapped. It wont be a problem if you never get the bike wet.

Ti wont corrode, but Ti posts end to be extremely expensive, and not light enough for the money imo.

Alu frame, go with a well made anodized alu post, and remove it once in a while, or after a wet ride.

[Kranswurm]

What a ridiculous thought. Besides the fact that it was a little inside joke between RAD and I, I have the freedom to choose exactly what bikes I want to work on and which not. If I don't like blue bikes, tough for anyone with a blue bike. If I don't work on kiddies bikes, I don't. What compels me to do so?

 

And as for that vexatious little yapping dingle berry-infested dog in agreement with you, he utters a little yelp at every challenge I receive on this forum. He seems to get kicks out of it.

 

LOL

I have a blue bike