Originally Posted by
thirdgenbird
on a related note, my rough math shows that a sub 6.3lb brakeless fixed gear bike is possible...
evidence
Well sure. But look at his supposed frame weight, less than your chosen crankset. And honestly I just can't see that bike being all that fun to ride. There is a reason why even the highest end road bikes weigh 14-16 pounds. Any lighter and one of two things happens; you're price skyrockets, or you loose significantly in the stiffness of the frame. I'd also bet the frame is like a 52 if not a 50.
Assuming you're building for the roads, I would focus not on weight but on durability and quality. Aim for something like 16 or 17 pounds, much more doable.
Also, olympic and world championship riders are not riding bikes that light. Must be a reason.