Or it could just be the bike. I have a cannondale badboy and it creaks, always at the same spot in crank rotation. Checked the bb, cranks, seat etc and finally took it in the the lbs to solve the problem.
It's a creaky bike. No cracks, just creaks. I was told some bike are like this.
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When sadness fills my days
It's time to turn away
And then tomorrow's dreams
Become reality to me