Stubborn seat tube!

funnights74

I had a bike fitting with Aidan Hammond recently and he suggested dropping the saddle height 2 cm's. Despite our best efforts it wouldn't budge. It's an Aluminum seat post and a carbon frame.My Lbs tried to help but nothings budging
Despite various oils etc nothing, if too much force is applied then the carbon will give and despite googling for some inspiration, even coca cola was mentioned no joy so far.
Any help would be appreciated.

onthefringe

What way did u put the coca cola on it?
I've used coke on plenty of that combo - carbon / alu and alu / carbon
Always worked ??
Take bb out..
Fill seat tube upside down internally with cola..
Leave over night --- use only actual coca cola ...

funnights74

I didn't, it seemed a bit left of field, thanks for your suggestion.

cajonlardo

Coca Cola does usually work.

Only try the following if you are willing to chance destroying the pillar.

Soak from bottom bracket with coca cola or wd40 etc with the frame upside down.

Take off the saddle.

Get two long screwdrivers with big handles. Put them in the clamp rails so that the handles are facing opposing directions and clamp down as tight as possible.
Get someone to hold the top tube at both ends. use the srew driver handles to exert as much force and as suddenly as you can.

I've had a few stuck down the years ( used to work in bike shops) I've never had one beat me so keep trying!

koutoubia

cajonlardo wrote: »

Coca Cola does usually work.

Only try the following if you are willing to chance destroying the pillar.

Soak from bottom bracket with coca cola or wd40 etc with the frame upside down.

Take off the saddle.

Get two long screwdrivers with big handles. Put them in the clamp rails so that the handles are facing opposing directions and clamp down as tight as possible.
Get someone to hold the top tube at both ends. use the srew driver handles to exert as much force and as suddenly as you can.

I've had a few stuck down the years ( used to work in bike shops) I've never had one beat me so keep trying!

What would you do if there is no gap under the bb shell to pour coke into it?

cython

koutoubia wrote: »

What would you do if there is no gap under the bb shell to pour coke into it?

Remove the BB and pour it in that way? Or are you suggesting a scenario whereby the BB shell doesn't open into the seat tube?

koutoubia

cython wrote: »

the BB shell doesn't open into the seat tube?

Yep!

cython

koutoubia wrote: »

Yep!

Funnel in through the bottle cage bosses? Otherwise probably need to sacrifice the seat post and cut the top off to pour down through it, though that will cost leverage if anything remains tricky then.

koutoubia

Havent tried the bottle cage bosses yet. Seatpost is cut. I have a feeling its a long mtb post for some reason.
Will try and see how far the seat post goes down and try and soak it.

iwillhtfu

What about drilling a hole through the seat post and placing a long screwdriver or bar through it then twist it.

I can't imagine it will stay stuck for long and if it doesn't budge fill with coke as above then place a bag around the open end and leave over night to see if it loosens it.

koutoubia

iwillhtfu wrote: »

What about drilling a hole through the seat post and placing a long screwdriver or bar through it then twist it.

I can't imagine it will stay stuck for long and if it doesn't budge fill with coke as above then place a bag around the open end and leave over night to see if it loosens it.

Tried the long bar trick both at home and bike shop!

Just gonna have to get a plastic seal down at the bottom and try and soak it .

iwillhtfu

koutoubia wrote: »

Tried the long bar trick both at home and bike shop!

Just gonna have to get a plastic seal down at the bottom and try and soak it .

Fill it with silicone should do the trick.

Yi Harr

I had the same issue. Thread on here somewhere which I've been meaning to update.

Tried everything you listed and eventually started trying to cut out sections of the seatpost to see if I could remove it that way. No joy.

Before you do your head in I'd suggest giving Brendan Whelan in the Bicycle Design Centre a shout. He reamed out the seatpost on my frame.