The bolt loosening had me scratching my head. As with everyone else I did not know why a bolt would loosen like that. Having had no info worth sharing I did not post until now. When I put a Brooks seat on my Burly tandem the seat would slide back no mater how tight I made the bolt. I solved the problem by shimming the seat rails with cut up pieces of aluminum cans. I also used aluminum shims between the handlebar and stem clamp on my custom chromoly Salsa stem . Neither have slipped or moved in over 29 years.