RACQUET RESEARCH

Using physics to help select a racquet

Customizing your racquets


Racquets are described as being __ points head-light or __ points head-heavy. A point is ⅛ inch, or 0.3175 cm. Points head-heavy (or head-light) are measured from the midpoint of the racquet’s length, so a balance that is 6 points head-light means that the balance point is ¾ inch toward the butt from the midpoint.

Formula for finding balance point shift:

\[ s = d \times \frac{m}{M + m} \]

\(s\) = shift in balance, in cm
\(d\) = distance from added weight to original balance point, in cm
\(m\) = amount of added weight, in grams
\(M\) = original racquet weight, in grams
Derivation

This formula finds the balance shift resulting from added weight at the tip, shoulders (9 and 3), or the butt. Change \(d\) accordingly. Here’s an example:

Tip-weighting Effect lead tape applied at 12 o’clock on head, 1 cm from Tip Measurements example is Wilson ProStaff 6.0 85, strung and gripped Results
Added Weight (\(m\)) (grams) Resulting Balance (minus = head-light) Original Racquet Weight (\(M\)) (grams) Racquet Length (inches) Original Balance Point (cm from butt) Distance From Original BalancePoint to Added Weight (\(d\)) (cm) Resulting Shift in Balance Point (\(s\)) (cm) Balance Point Shift, in Points (Point = ⅛-in. or 0.3175 cm) Points Shifted for the last added weight
0 -8.0 354 27 31.75 35.83 0.0 0.0 0.00
5 -6.4 354 27 31.75 35.83 0.5 1.6 1.57
6 -6.1 354 27 31.75 35.83 0.6 1.9 0.31
7 -5.8 354 27 31.75 35.83 0.7 2.2 0.31
8 -5.5 354 27 31.75 35.83 0.8 2.5 0.31
9 -5.2 354 27 31.75 35.83 0.9 2.8 0.30
10 -4.9 354 27 31.75 35.83 1.0 3.1 0.30
11 -4.6 354 27 31.75 35.83 1.1 3.4 0.30
12 -4.3 354 27 31.75 35.83 1.2 3.7 0.30
13 -4.0 354 27 31.75 35.83 1.3 4.0 0.30
14 -3.7 354 27 31.75 35.83 1.4 4.3 0.30
15 -3.4 354 27 31.75 35.83 1.5 4.6 0.29
16 -3.1 354 27 31.75 35.83 1.5 4.9 0.29
17 -2.8 354 27 31.75 35.83 1.6 5.2 0.29
18 -2.5 354 27 31.75 35.83 1.7 5.5 0.29
19 -2.3 354 27 31.75 35.83 1.8 5.7 0.29
20 -2.0 354 27 31.75 35.83 1.9 6.0 0.29