If you haven't already tried this:
1. Loosen your seat clamp binder bolt.
2. Tap on the bottom of the clamp with a hammer or something. Make sure it comes free from the fixed part of the seat post.
3. Now try readjusting your seat tilt.
Sometimes the bottom portion of the seat clamp doesn't come loose from the fixed part of the seat post. When that happens, the seat goes back to where it was as you tighten the bolt.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.