Off Center Hits and Perimeter Weighting
Off center hits have two downsides - the rebound velocity of the ball is reduced and the ball is misdirected. Perimeter weighting mitigates the downside effects at the expense of higher swing weight and less maneuverability.
If you are blocking a shot at the net with the paddle positioned horizontally the ball will pop up or pop down depending on whether the impact location is above or below the center line of the paddle face. If volleying or serving where the paddle is positioned vertically the ball with be misdirected right or left depending on the impact location.
Slow motion video of 50 mph ball impacting a Ruby paddle face 2" off center. The ball rebounds off axis at a reduced velocity compared to an on center hit. A speed of 50 mph was chosen as representative of a block at the net requiring quick hand positioning that has a high probability of an off center hit.
Rebound Angle
Instead of rebounding directly back along the axis of the inbound ball, the ball is misdirected 12 degrees to the side. The angle could be larger or smaller depending on how tightly the paddle is gripped. Adding weight along the sides of the paddle reduces the error. Four 3 gram lead strips were added. Two at the 3 o'clock position; two at the 9 o'clock position. The Ruby's twist weight increased from 6.8 to 7.9. The swing weight increased from 117 to 123. The misdirection angle was reduced from 12 degrees to 6 degrees.
The ball is pictured just after a 50 mph impact with the paddle face 2" off center with no perimeter weighting. The paddle face can be seen twisting slightly resulting in an 11 degree offset in the rebound angle. The impact is violent at 50 mph and it's doubtful whether anyone can grip the paddle tight enough to prevent rotation and ball misdirection.
Adding perimeter weighting cuts the misdirection angle in half, but the downside is less maneuverability due to the increased swing weight and increased static weight.
Off Center Rebound Velocity - Ruby
The reduction in rebound velocity of a 25 mph ball is plotted for the 16.3" x 7.7" Ruby. The stock Ruby's velocity decreases by 6% and 15% as the impact location moves 1" and 2" off center. Adding weight (12 grams total to the sides) increases the mass of the paddle (plow through) and, as expected, the result is a slight bump (0.25 mph) in rebound velocity compared to the stock paddle. However, the added weight does not have a significant effect on the percentage decrease in velocity as the impact location moves off center.
I can't count the number of times I've hit the ball off center while trying to execute a dink where the outcome is a ball dropping into the net instead of over the net because of the reduced velocity.
At an inbound velocity of 50 mph there is a "bump" in rebound velocity of about 1 mph due to the added perimeter weighting. The added weight does not have a significant effect on the percentage decrease in velocity as the impact location moves off center.
Off Center Rebound Velocity - Pulse V
The reduction in rebound velocity of a 25 mph ball is plotted for the 15.8" x 8.1" wide body stock Pulse V and a Pulse V with two 3 grams strip on each side. The stock twist weight is 7.5. The twist weight with the four 3 gram strips is 8.7.
As expected, the wide body Pulse V with a higher twist weight has a lower rebound velocity fall off (12% v 22%) at the 2" off center impact location compared to the hybrid shaped Ruby.
The wide body paddle has two advantages when hitting off center. One, a wide body paddle inherently has a higher twist weight mitigating the fall off in velocity (and angle of misdirection). Two, an off center hit on a wide body paddle is always further away from the dead spot on the edge when compared to a narrower paddle mitigating the fall off in velocity.
