Triangulating weight, balance, and swing weight

Once I had decided to switch to the Wilson Pro Staff RF 97 Autograph, I ventured out to find 3 true to spec frames. As mentioned before, Wilson and some other brands' racquets come out of the factory quite differently. Technifibre for example recently increased their official tolerance from 5 to 7 (grams for weight and millimeters for balance), so basically a spread of 14 for each measure! At least they print that on their frames...



I had tested the RF 97 in different weight, balance, and swing weight combos for more than 30 hours, and found that even a slight increase in balance and swing weight over the official spec made the racquet feel as heavy as often reported. However, I loved the feel of a true to spec (or slightly below) frames. So I had no choice but to become a picky customer when it came to the measures.

Even if you only want 1 racquet, you may have found the weight, balance, and swing weight combo that works for you. There are a few situations in which you might have to triangulate a bit, for example:
  • you want to pick the right racquet(s) off the shelf at your local tennis shop, but they're not very keen removing the plastic wrap around the handle, cutting out the card board, stringing the racquet up etc
  • you fell in love with a demo or someone else's racquet, but they're not very keen on you cutting out their favorite string job, removing their grips etc.

Both of the above actually happened to me, so here's what I found as I was looking for a RF 97 with a true to spec 340 grams and 305 mm balance point in-store:

The cardboard in the racquet head...
  • weighs ~14 grams
  • moved balance up by ~8 mm (from 305 to 313)
  • increased swing weight by ~41 kg cm² (higher than the string value below - maybe due to air resistance?)

A (Champion's Choice) string job...
  • increased weight by 16 grams
  • moved balance up by ~9 mm
  • increased swing weight by ~31 kg cm²

The Wilson Pro Overgrip...
  • weighs ~4 grams
  • moved balance point by ~3 mm
  • increased swing weight by 1 kg cm².

The plastic wrap around the handle weighs ~2 grams, so you'll have to subtract that from your measure. The effect on swing weight is negligible though.

A 5 gram dampener increased swing weight by 2 kg cm².

A fully loaded frame with string, overgrip, and dampener weighed 340 + 16 + 4 + 5 = 365 grams. All that moved the balance point up by ~8 mm, so a true to spec model with a naked 305 mm balance point would have a fully loaded balance of ~313 mm. I still have to measure swing weight on that one - should be in the mid 330s...

Note that with ~340 grams, the RF 97 is one of the heaviest frames out there. So on lighter frames, cardboard, string, grip etc should have a higher relative impact on balance and swing weight.

You can find some tips on measuring weight and balance in this post. For swing weight, you'll need something like the Alpha Accu Swing 2, the Babolat Racquet Diagnostic Center, the Gamma 3 in 1 Racquet Test Center, or the Prince Precision Tuning Center. Luckily some tennis shops are starting to recognize the importance (and business opportunity?), and are investing in these machines. As a workaround, you can check out Racquet Tune, which features a swing weight calculator.

For reference values, I recommend visiting Tennis-Warehouse.com, where the staff actually measures multiple frames and then posts the averages on the racquet description pages (RF 97 example). Note that not only weight, but also balance and swing weight are taken from strung racquets.

There are some more sophisticated tools and formulas out there to calculate all this, but hope this info and approach gets you thinking in the right direction. And most importantly, gets you 99% the racquet you want within 5 mins :)

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