Originally Posted by LeeD
I don't know.
Is it because they measure the "stiffness" differently?
Is it initial deflection?
Is it longer range deflection?
A thicker beam should be quicker rebounding, while a thinner beam might take more time, with thicker beams usually being more thin walled, while thinner beams can often be made with thicker materials in the walls.
This is also my current thinking on the matter. I think it has to do with the rebound speed of the frame. When stiffness is measured on an RDC machine I believe a set force is applied to the racket the "stiffness" is just a reflection of how far the racket bends when this constant is applied. So, this number would not directly reflect how quickly or efficiently the racket returns to it's natural state after striking a ball.
For those of you unaware of how stiffness is measured, take a look at 1:35 on in this video:
...and yes the balance and sw are also matched.