It's all about wind resistance on high end bikes, that's why if you notice even the cables are all inside the frame. Every part of the bike is considered for it's aerodynamic performance.Not sure what you mean here, in a vacuum they would both fall at the same rate but obviously in air due to wind resistance the brick will fall quicker. Are you saying that if the wind resistance hasn't increased (as was the case in my example) then the extra weight does mean I will travel faster? Or that I will travel at the same speed in both cases?
The reason carbon is used on high end bikes is as much for stiffness as weight saving, a stiff bike means that the riders efforts all go through to the road rather than being lost distorting the frame and forks. I know this is all very small % increases in performance and if you put me on the best bike in the world and Chris Froome on a Raleigh Chopper, Chris would beat me over any distance. Like golf clubs, tennis rackets and all sporting equipment its all about giving yourself a tiny edge over competitors. And of course they look the mutts' n*ts!
Some people I understand will pay more than £10.00 for a watch, that tells the time as well as any for £10,000 or more. Life is about choices.
Brake cables through the forks.
No cables....
Atb, David