I had a aluminum (some sort of named aluminum alloy that is skipping my memory right now) Schwinn racing bike that cracked at the top of the head tube and went down from the headset to about an 1/2 inch. I never hit anything ever with the bike, so how that happened I don't have a clue, I rode if for about 3 years, but after that I swore off aluminum bikes. I also have friends who had problems with their aluminum bikes...but to be honest I have some friends who had theirs for a long time, most notably Cannondale and Klien. Keep in mind, as of 2011 or 12 Cannondale moved their production to China, I would be extremely leery of those.