- Jun 10, 2004
thoughtforfood said:Actually, even without a larger contact patch, you still lose energy because of the manner in which a round object reacts to altering its pitch in relation to its line of travel. You are gonna lose energy, no way around it.
The point is, what amount of energy is lost? Is it significant to the system in question? Is the energy lost greater in magnitude than the noise in the system?
The idea that something has to be lost is a bit too simplistic. Of course, by the second law of thermodynamics, something has to be lost; however just because something is lost doesn't mean that the system responds in any noticeable way to that loss.
John's point and the point of all the analysis ever done on this, uhm, point, is that the losses are statistically insignificant and are lost in the noise. Moreover, if you create a model wherein the system is perturbed so much that there are significant losses, then that perturbation will exist even for stiff systems. Example: if you model a 350lb rider with a cadence so bad that the force applied to the pedals is applied at a 60 degree angle to the bike plane's normal, the energy applied to BB, normal to the bike's plane will be the same whether the bike is made of pot metal, CF, or Inconel X. The frequencies at which the frames respond might be different, but the energies won't change.
Measuring frame deflection doesn't really tell you anything instructive. It'll only verify that stiffer frames, i.e. frames with higher effective spring constants, deflect less for a given force input. It'll also only show that a given energy, U, put into frame one is the same as put into frame two. That doesn't change. Differing spring constants don't limit the amount of energy put into a system.