I have a Kalloy adjustable stem that I re-sized, on my Ross Eurotour. I ride this bike almost daily. One morning, a heavy sheet of drywall broke loose from our detached garage ceiling and fell on handlebars at the stem. I heard the noise from inside the house. Absolutely no damage occurred. I'm about 3/4 of the way through the new set of tires I put on about that time. No problem with the bike or the stem.