RESOURCES
A collection of the most important racquet customization resources.
Calculator
Inputs:
Consistency: Recoil weight can apply to either strung or unstrung frames. If you want strung recoil weight, makes sure you are input strung static weight, balance point and swingweight. Likewise for unstrung specs. Mixing strung and unstrung inputs will lead to useless results.
Static Weight: The mass of the racquet. Best measured in grams (g). Can be measured with a kitchen scale. Recommended to be accurate to 1g.
Balance Point: Centre of mass of your tennis racquet. Sometimes referred to by inches or points headlight, its best measure in centimeters (cm) or millimeters (mm) starting from the butt of the racquet. This can be measured using a balance point, a rod and a ruler, or my preferred tool, the Briffidi BP1.
Swing Weight: The inertia of the racquet around your hand. Measured in kgcm². You’ll have to get this measured at a pro-shop using a specialty tool like a Babolat RDC. The cheapest option to do this accurately yourself is with the Briffidi SW1.
Outputs:
Recoil Weight: Recoil weight describes the inertia of the tennis racquet around the balance point.
Recoil Weight = (Swing Weight) - ((Static Weight) x (Balance Point - 10)²),
Where Recoil Weight and Swing Weight are measured in kgcm², Static Weight is measure in kg, and Balance Point is measured in cm.
Polarization Index: An indexed figure that helps us understand how the mass is distributed along the Y-axis of the racquet. The greater the polarization index, the further the mass is located from the balance point. The lower the number, the more the mass is concentrated around the balance point. Figures between 0.45 and 0.52 would be considered “normal.”
The Polarization Index = Recoil Weight ÷ Weight in Grams
MgR/I: Describes how “easily” a racquet comes through the ball. This runs under the assumption that the arm and the racquet create a “double pendulum.” Higher numbers (closer to 21.0 and above) swing faster, or more easily, and lower numbers, closer to 20.0, swing slower, or feel more clubby.
MgR/I = (Static Weight x 980.5 x Balance Point) ÷ (Swing Weight + (20 x Static Weight x Balance Point) - (100 x Static Weight))
Where Recoil Weight and Swing Weight are measured in kgcm², Static Weight is measure in kg, and Balance Point is measured in cm.
Notes:
Static Weight should be inputted into the calculator using grams (g), however, the formulas given about use Static Weight in kilograms (kg). This is to clean up the look of the formulas to keep them easy to understand. The calculator above will automictically convert your inputs (g) into the formula’s requested (kg), as us tennis players typically use grams to describe the mass of our racquets.
Recoil Weight
It's more important than you think!
Recoil weight describes the inertia of the tennis racquet around the balance point. This helps us understand how much mass the racquet carries and where its distributed. The further away mass is located from the balance point, the great the recoil weight. The more mass there is, the great the recoil weight.
To calculate recoil weight, you’ll need to measure the Swing Weight, Balance Point and Static Weight of your tennis racquet. Be as accurate as you can, especially with the balance point, as even small changes to the inputs can lead to significant differences in the outputs. If you feel uncertain with your ability to calculate balance point, I highly recommend the Briffidi BP1. This tool has saved me a lot of head ache. I’m not an affiliate for Briffidi, I just really respect the company and the product.
Recoil Weight = (Swing Weight) - ((Static Weight) x (Balance Point - 10)²)
Where Recoil Weight and Swing Weight are measured in kgcm², Static Weight is measure in kg, and Balance Point is measure in cm.
Optimizing for Recoil Weight
It has been hypothesized that there may be optimal recoil weights for a given arm length. For simplicity, the table below uses player height, as it’s a strong indicator for arm length that most players already know. This voids any confusion on where exactly the arm should begin when measuring from the shoulder.
Brando. Who Cares about Recoil Weight? Talk Tennis Warehouse. Post #25.
Further Reading…
I highly recommend reading these threads, authored by my friend Brando.
Here are a few videos, both by us at TennCom, and a few of our other friends on YouTube.
Swing Weight
A heavy hitting topic.
Swingweight describes the inertia of the tennis racquet around the 10cm point (measured from the buttcap). 10cm is chosen because that’s typically where player’s hold the racquet. This helps us understand how much mass the racquet carries towards the tip of the frame. The more mass there is, the greater the swingweight. The further that mass is located away from the hand, the higher the swingweight. Note that adding weight in the buttcap will NOT reduce swingweight. The only way one can reduce swingweight is by reducing mass, such as using lighter strings, cutting off the bumper guarder or shortening the handle.
There are manual methods of measuring swingweight, however, they are susceptible to significant human error. I recommend having it measured using an electronic tool, like a Babolat RDC, at your nearest pro-shop. The best way to measure swingweight at home is by using the Briffidi SW1. Briffidi did not pay me to place this link here, nor do I have an affiliate deal with them. I just think they make an excellent product that is well worth the price for tennisnerds everywhere.
Swingweight is measured in the units kgcm². The distance is squared because the further way from your hand the mass is located the most significant impact that mass will have on swingweight.
Increasing swingweight is the most effective way in increasing power, spin and stability in your racquet. You’ll get the most “bang for your buck” by adding weight at 12 if your sole goal is to increase swingweight.
Optimizing for Swing Weight
A player’s ideal swingweight is subjective. Different players have different strengths and techniques that will lead to different optimal swingweights. Higher swingweights mean you can hit the ball harder, however, only if you can maintain your swing-speed.
Further Reading…
Twist Weight
Off-centre thinking.
Twistweight describes the inertia of the tennis racquet around the Y-axis, or, how the racquet’s mass contributes to the torsional stability of the racquet. The more weight you have towards the 3 and 9 o’clock locations of the racquet, the more torsionally stable that racquet will be and the better it will be at handling off centre shots.
Twistweight is measured in the units kgcm².
Previously, there were no viable ways to accurately measure twistweight. The best we could do was estimate it by subtracting swingweight from spin weight. Spin weight is measured the same way swingweight is, except the strings should be parallel with the ground instead of perpendicular. The spinweight or a given frame will ALWAYS be greater than the swingweight of the same frame. Now we can measure a racquet’s twistweight using the Briffidi SW1 in conjunction with the twistweight adapter. There are other products in the works for this, however, they are not yet available.
It is hard to say what are considered normal, high or low twistweights. Previously, the only resource we had was Tennis Warehouse’s twistweight database. If we assume these numbers are correct, I’d call 14.0-14.5 normal, under 14 as low, and over 15 as high. Unfortunately, we do know how these figures are generated. The numbers I’ve gotten using my twistweight adapter regularly come in over 1 point lower in twistweight than what the database shows. At this time, my sample size is insufficient for any significant takeaways.
Further Reading…
Support
If you have any questions, corrections or suggestions, please use the Contact Us page. These are some of the more complex topics in the world of tennis racquets and its TennCom’s mission to make things as accessible as possible. If you found a video on swingweight, twistweight, or anything else, that really helped things “click” for you, please share it, I’d love to add it to the “Further Reading…” sections of the above articles.
More topics will be added to this page as my understanding grows. Stay tuned for updates on MGR/I and more.
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