Carbon Frame/Alloy Seatpost

daveconn10

Yep you guessed it...its seized/fused/joined etc etc and there aint no shifting it. Any advice that isnt going to crack the carbon?? Cheers

07Lapierre

Clamp the seat post and use the frame as leverage??

dave2pvd

Just don't apply too much leverage. The weak point is usually right below the seat clamp.

I had fun with this pretty Ridley last year. The Thomson seatpost was far stronger than the CF frame:

pixcil

Hello Dave,

unfortunately had similar problem, mine being carbon seatpost into a carbon frame via a alloy/steel shim.Solidly jammed so eventually had to cut seatpin and gently cut the pin from inside cutting in four places. with the gap made from the cutting was able to gently push a jewellers screwdriver, (the gaps giving the pin space to move) down the side and several hours later got the bugger out. Sounds drastic but couldnt think of anything else but it's a long slow process but didn't put any undue pressure on the carbon frame. Just lots of pressure on yourself! cost me a carbon seatpin but can live with that rather than a ominous crack!

Good luck

Holyboy

Find a shop with some seat tube reamers,adjustable ones if possible,i know Mikes bikes in dun laoghaire has some because I bought them when I worked there,if your in dublin you could try them,its a long,long and horrible job but ive done it before.

Side Show Bob

Holyboy wrote: »

Find a shop with some seat tube reamers,adjustable ones if possible,i know Mikes bikes in dun laoghaire has some because I bought them when I worked there,if your in dublin you could try them,its a long,long and horrible job but ive done it before.

Hi I'm Just curious, but how would a reamer help to remove a stuck or jammed seatpost?

Holyboy

Side Show Bob wrote: »

Hi I'm Just curious, but how would a reamer help to remove a stuck or jammed seatpost?

Just cut it off close to the frame and start reaming the inside of the seat post, if the seat post walls aren't too thick it's not so bad but if they are it can be a lengthy process, and obviously be very careful as you cut closer to the carbon but when the aluminium gets thin enough it'll just come away.

Side Show Bob

Holyboy wrote: »

Just cut it off close to the frame and start reaming the inside of the seat post, if the seat post walls aren't too thick it's not so bad but if they are it can be a lengthy process, and obviously be very careful as you cut closer to the carbon but when the aluminium gets thin enough it'll just come away.

Oh... Ok thanks!

dave2pvd

That's what we ended up doing with the Ridley. Countersunk the protruding piece of seatpost, then went in with a series of bits. Used a reamer to thin the last bit of wall left. Thing is, some alloy seatposts are 7000 series. The stuff is hard and brittle. It was extremely difficult to get the remaining slivers of metal out of that bike. 7071 (or whatever the Thomson was) prefers to snap than bend. Each time you pull a sliver with the pliers, you just break a small piece off.

munsterleinster

So what's best prevention?

dave2pvd

munsterleinster wrote: »

So what's best prevention?

ALWAYS use carbon fiber assembly paste for seatposts/frames that are 'dissimilar metals'. CF qualifies as a dissimilar metal.