Originally Posted by
Racer Ex
Source: For which statement? The aero advantage pretty well documented, go over to BTR and do a little searching, there's a lot of info there with cites and links for specific tests and studies.
Ok, the round tubes are a bigger difference than I thought, but not quite 88 seconds. I went off Uwe Peschel's normal bike --> Cervelo numbers that slovid posted some time ago. That showed 17W difference just from changing frame and fork at 28mph. Making a lot of assumptions and using kruetzdotter, I come up with Cancellara losing to Bodrogi by 7 seconds on a road frame.
Originally Posted by
Racer Ex
For power transfer any mechanical engineer can explain power loss during the pedal stroke because of frame deflection.
You've
read this?
Not only are mechanical engineers unable to explain it to me, Cannondale's engineers are unable to explain it. Nobody anywhere that I have found has demonstrated or measured power loss between a decent steel frame and a stiff carbon fiber frame. When my email chain with Cannondale escalated up to Engineering, their response was "...it's too complicated to measure, but is intuitive."
At some level, there has to be a minute loss to heat, because no material is a 100% efficient spring, but that doesn't necessarily tip the advantage to carbon fiber. Everyone knows carbon fiber is a dampener, which means it turns bending energy into heat. Even though a CF frame may flex less than steel, it still flexes, and it's possible that its dampening properties draw more energy out of a pedal stroke than steel's microscopic spring inefficiency.
Either way, frame flex doesn't amount to squat for any material as long as your drivetrain isn't rubbing.