i know somebody who overtightened a bike tuning stand on his giant tcr composite zero, and put about a 3 inch crack in the top tube, near the seat post. its not like a split open crack, but more of a line down the carbon fiber, but definately its a crack like weak spot. so the question is, hes willing to sell it cheap, so is it safe to ride on? i would love to upgrade to a carbon bike, but dont want to spend so much money, so with a small, 3 inch crack, will i be in danger when riding it? im fearing yes, so im kinda staying away, any advice? thanks in advance