Ah, Yet another stuck seatpost.. thread... hundreds of responses already archived here on this forum..

The effort to to remove it will make you want to buy another seat post ... got a pipe wrench? you need a handle..

remove BB turn bike upside down and pour your chemical in from underneath ..


somebody shoved a post i upside down ?
'
they should look like this, at least diameter stepped down to take a saddle clip ..


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