So my gf has bought a road bike with a carbon post in an aluminium frame. It’s stuck fast! What are the best ways to remove it? Im desperate as shes really upset she cant ride it! I can write of the post if necessary!

Sure it is carbon and not “carbon wrap”? If you really want it out loosen clamp bolts and twist by the saddle from side to side forcing upwards. Standing on a pedal helps.

For more dramatic effects. Clamp the seatpost in a vice and lever the frame. Then buy a new seatpost.

Be careful using anything, including the frame, for additional leverage

ParkTools
Sodium hydroxide (caustic soda or lye) will attack aluminium (and human tissue!), so don’t use that

For the next time you need to guard against galvanic corrosion, carbon fibre and aluminium don’t play well together in some environments. Consider an aluminium seatpost with your aluminium frame, but whatever material you choose periodically remove and refit the seatpost

Coca-cola

Definitely not caustic soda. Or Coca Cola. You don’t want to attack the aluminium or you’ll wreck the frame.

First step to try is leverage. Take the saddle off, and clamp the frame upside down in a vice, clamping by the head of the seatpost. Then twist. If you can, remove the bottle bosses and squirt loads of WD40 down there first to try to break the seal.

If that doesn’t work, then you need to cut it out. Chop off the post about an inch up from the frame, then using a hacksaw blade or a jabsaw cut down vertically inside the post. The aim is to slice the carbon post into sections without cutting the aluminium frame, then pry out the pieces.

Once you’ve got them all out, you’ll need to run a hone or reamer down there to clear out all the crud and corrosion.

Heat is your friend….

Soak in penetrating fluid overnight

Heat frame and use a seat as leverage

Carbon fibre has a lot lower coefficient of expansion than aluminium which you should use to your advantage

You may be able to unstuck it by hammering it IN to the frame a little, just to break the bond between the two materials.

unless

So my gf has bought a road bike with a carbon post in an aluminium frame

means it’s new (though unlikely), in which case leave well alone and get back to the shop

sadly its not new, it was bouhght through ebay. Im not sure where we would stand on getting a refund as well, im worried that it wouldnt come out at all?

ask the seller to take it back he must have known it was stuck .if he says no report it to ebay .

ask the seller to take it back he must have known it was stuck .if he says no report it to ebay .

This, unless you went to pick it up, then IMO you’re fault for not checking.

Otherwise, cut it out.

Seller may not have known tbh- road bike, after all.

Done a couple on mountain bikes and whacking it downwards has been effective- you’re not that bothered about what direction it moves in initially, you just need to break the seize. But that sort of thing’s got to be a bit chancier with a more delicate road frame.

eBay will support pretty much any return even if you picked it up yourself

I’d be looking in that direction and get a new bike rather than attempt to repair it

Seller must have known about stuck seatpost,surely?. worth contacting Ebay to see about a refund,unless GF is smitten with bike or it is a real bargain. Stick the kettle on and hit the post/frame area where it is fast see if that helps. This may be worth trying before you chase Ebay as it usually wont leave any trace. Hope ya sort it… . It is galling,when this happens (sorry could not resist) 🙂

Seller may not have known. I sold a frame and ìt wasnt until I went to strip it I realised it was stuck. Had the full bike sold i wouldn’t have noticed.

I got it out in the end after trying alsorts by clamping seat in a vice and twisting the bike around