Stiffest frame?
08-18-07, 06:48 AM
#26
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[QUOTE=waterrockets;5091777]Yeah, energy return to forward motion is the biggest hangup people have with this idea.
I'm not condoning noodles here that would allow massive amounts of drivetrain flex.
Why not?
I'm not condoning noodles here that would allow massive amounts of drivetrain flex.
Why not?
08-18-07, 07:15 AM
#27
Making a kilometer blurry
08-18-07, 04:52 PM
#28
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Very interesting and points well made by all. I'm pursuaded of the argument that energy stored in the frame *can* be returned in a manner that can 'drive' the rear wheel. But as others have mentioned, I believe that some of that energy will be lost, however small. I would add that since the frame is flexing, if the wheels remain in contact with the road and do not slip, then energy stored in the frame would also be lost through friction between the tire and road surface on both wheels, which could add up.
In theory, it should be possible to build a frame such that the resonant frequency of the frame provided a 'boost' to smoothen out torque around the pedal rotation!
Unless some clevor material engineer comes up with that, I still believe that if you can prevent the frame from flexing, the only place for energy to go is through the chain to the rear wheel. And you've got the added bonus that you improve handling and reduce the risk of link chains derailing. But at the expense of a much sorer bottom!
Many thanks.
In theory, it should be possible to build a frame such that the resonant frequency of the frame provided a 'boost' to smoothen out torque around the pedal rotation!
Unless some clevor material engineer comes up with that, I still believe that if you can prevent the frame from flexing, the only place for energy to go is through the chain to the rear wheel. And you've got the added bonus that you improve handling and reduce the risk of link chains derailing. But at the expense of a much sorer bottom!
Many thanks.
08-18-07, 08:20 PM
#29
Making a kilometer blurry
Yeah, I see what you're saying, and appreciate your doubt. I remain convinced that it makes no difference at all. There are no data saying otherwise. Remember the Sean Kelly test -- he beat up on a different frames trying to find a difference in results and found none -- and one of the bikes was a total noodle, under a powerhouse like him.
I agree that tandems are more complex, but in the range you're considering, the difference in flex can't possibly amount to more than something to talk about.
I agree that tandems are more complex, but in the range you're considering, the difference in flex can't possibly amount to more than something to talk about.
08-19-07, 11:29 PM
#30
shut up and ride
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here's my take on frame flex... the rider is not losing any or much energy due to frame flex but the difficulty comes in handling. a flexy frame is going to harder to control to ride in a straight line and harder to put out full power (whether a tandem or single). a flexy frame won't use power but might not let you use full power or use it as effectively as a stiff frame.
