[jonKranked]

soooooo aluminum seatpost, steel frame. the seatpost is seized in there good. does any one have any secret tips other than hitting it with some bike aid and wailing on it with the problem solver (aka hammer)?

 

[binary visions]

Sit the bike upright and spray some penetrating lube around the seat collar. Let it sit, hit it with a little more, etc. It won't get too much in there, but it'll start.

Then flip it upside down and spray a bunch in via the bottom bracket, into the seat tube. Wait, spray some more... You can put a lot in there, and give it an hour in between sprays to really penetrate. I honestly don't know what the maximum "effective" time would be (that is, it may have soaked in as much as it can in 10 minutes), but no need to be in a hurry.

Then, clamp the seat post in a bench vice, hard. Carefully and evenly push on the frame - the frame will act as leverage to twist the seat post loose.

 

[Dartman]

http://sheldonbrown.com/stuck-seatposts.html

Good luck!

 

[dirtydirtysouf]

http://sheldonbrown.com/stuck-seatposts.html

Good luck!

Aluminum seatposts frequently become stuck by corrosion also, and penetrating oil is almost useless against aluminum oxide. Fortunately, aluminum oxide can be dissolved like magic by using ammonia.

neat didnt know this

 

[jonKranked]

well, ultimately i had to cut the post from the inside. The post and frame had co-corroded together. I'll remember the ammonia trick for next time (which hopefully won't come).

 

[w00dy]

Alternate heat and cold. The Aluminum has a much higher rate of expansion due to heat.

 

[jonKranked]

Alternate heat and cold. The Aluminum has a much higher rate of expansion due to heat.

i actually tried that. i sprayed canned air upside to expel the liquid CO2 into the frame (which actually cooled it to the point that frost formed on the outside of the frame) then held a towel soaked w/ boiling water (extremely carefully) to the outside of the frame and it still wasn't enough to get them apart.