How do you measure swingweight?
To determine swingweight, you must swing the racquet or put it into a machine that does so. You can't determine swingweight just by holding the racquet still. The easiest method to measure swingweight is with a commercial machine such as those made by Babolat, Pacific, or Alpha. These machines measure how difficult it is to swing the racquet around an axis located 3.94 inches (10 cm) from the butt-end of the handle. The end of the racquet at your wrist would be a more logical location for the axis, but it has become the industry standard to measure at the 10-centimeter mark because that is the easiest location for the machines to swing a racquet.
Why is swingweight important?
Of all normally measured racquet parameters, swingweight might be the most important factor in the feel and performance of a racquet. It takes into account the weight, the distribution of the weight, and the torque necessary to accelerate a racquet of given weight distribution. It is an indicator of feel, maneuverability and power. A higher swingweight has more power at the same swing speed. However it is also more difficult to accelerate the racquet up to that speed. If you cannot maintain racquet speed at the increased swingweight, you will actually lose power. It all depends on what you are looking for. If you are a big serve and volley player, you might want a lower swingweight racquet so you can generate lots of head speed for the serve and have maximum maneuverability at the net. If you are a baseliner and can generate plenty of racquet speed at any swingweight, then a higher swingweight might be for you.
When you are thinking about the sometimes confusing difference between balance and swingweight, remember this: a 10 gram racquet and a 350 gram racquet can both have the same balance point, but their swingweights will be radically different. "Head-light" and "head-heavy" therefore don't mean anything unless you are comparing racquets of the same weight. If they are different weights, only the swingweight will tell you which is more powerful and which more maneuverable. A head-light racquet can have a higher swingweight than a head-heavy racquet and therefore be more difficult to swing. That is why swingweight is the most reliable indicator of how a racquet will swing and feel.
How do you change swingweight?
First, you cannot (without drastic measures) lower a racquet's swingweight). That is why it is best to buy a racquet that is lighter than you will ultimately play with, because just about all customizations, whether they be for balance, swingweight, or twistweight, will increase the weight of the racquet. You increase swingweight by adding lead tape anywhyere along the length of the racquet, on either side of the pivot point. The pivot point is typically considered to be 3.94-inches up from the buttcap, under the knuckle of your first finger, but it can be a different distance from the butt cap if you grasp the racquet farther up on the racquet or farther down toward the butt cap. The farther away from the pivot point you add the lead tape, the more the swingweight will increase. Or conversely, the farther away from the axis you add weight, the less you have to add to achieve any desired increase.The 3 and 9 o'clock positions (usually the widest points on the head) are the most popular positions to add weight because that will also maximize twistweight (stability).