Seat post wont go in

[Joe24]

Its the right size. 27.2, like the old seat post. Its on my 531 frame I've greased it up, went in so far then stopped because it was too tight and wouldnt go in further.
I sanded down the inside to get rid of the paint from where, and tried again. Then tried so i got all the paint out from inside. Greased up and went in. Goes in so far but then it dont go in further. It looks like there is a lip in the tube where the post is going, about 1cm down the tube, maybe less. Not from me sanding it.
Has the two bits that squeeze together been squeezes together too much and just need opening? Says on the other post 27.2 and the new post is 27.2.
So any tips on getting a post into a tight hole?

 

[gbb]

I had the same getting a new (cheap) seatpost into my Raleigh 531....
I lightly greased the post and used the seat to turn and push the post down into the tube.
It was hard...and i dont fancy getting it out again.

At work, i'd get a steel rod (about 6 inches long) and hacksaw cut a slot into it, about 1 inch deep.
Get 2 or 3 inches of fine emery tape and locate it in the slot, the wrap the remainder round itself (abrasive side out of course)
Put the steel rod into a battery drill and you have a tool for cleaning out tubes.

 

[Joe24]

Bloody hell. The old one, which has 27.2 wrote on it slipped straight in Unfortunately the mount ontop of the post is broke so i cant use that one. I got the new one in part of the way, and its slightly stuck now. Going to try and yank it out, sand down inside more then grease it up.
Bloody thing.

 

[alecstilleyedye]

is the new seat post longer than the original? it may be catching on some imperfection around the bottle cage mounts.

 

[rustychisel]

It looks like there is a lip in the tube where the post is going, about 1cm down the tube, maybe less.

Not a bottle mount.

 

[Joe24]

Yeh, but it hasnt got down that far yet When i took it into LBS they said they will shove this thing in it to clean it out. I havent got a rod which i can fit down and keep hold of the sand paper to clean it all out.
Managed to get it out aswell. Was bloody hard, lots of twisting and pulling at the same time.
Lip is right at the top, about 0.5cm from the top.

 

[PatrickPending]

had a similar problem here - measured the old seatpost - turns out it was 27.15mm (tho it had 27.2 stamped on it) new one just a shade bigger than 27.2. Kind person in the workshop were I work took a fraction off the post for me - worked for me!