I'm a bike mechanic and I recently had a customer wanting to switch over to fixed gear after seeing/riding my bike, only thing is he has a Trek Madone, which is full carbon with vertical drops. I don't know if the frame can handle the torque of being fixed, I've heard that carbon frames tend to crack and splinter under the stress and also I've heard that's a rumor. Just seeing if anyone has tried with a carbon frame or know anyone who has or have seen the end results of such a conversion. I know chain tension would be a problem and I could probably use an eccentric bottom bracket or hub to help out, but I just wanted to get some opinions or see if anyone has done/seen this before. Thanks everyone.