Originally Posted by JohnB
Tonight I played with 2 identical rackets and customized to same endspecs, 327 g, 33.3 balance, 335 sw.
One racket had all the added weight at the sides and the other one in a more polarized manner.
The played very different despite having the same curve (and the same MgR/I). I am not only referring to ball trajectory, but also the felt racketheadcontrol. The polarized one has a whippier feel than the other one.
The equivalent mass is the same for both rackets, but do you know why they play so different? I think I know why just by experience, but it would be great if there was a scientific explanation.
travlerajm is correct that they have a different twist weight (moment of inertia around the y-axis). As I discussed above that doesn't influence the speed of the swing that much (and thus not the curve). However, it does influence the feel of the racquet, especially at impact. Placing weights at 3 and 9 increases the twist weight whereas placing it at 12 doesn't. A racquet with high twist weight feels less "wobbly" i.e. it is more difficult to rotate around its length axis. It can also handle an off line hit a little better (if you ever miss the sweet spot) and transfers a little less twist to the arm.