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Racquet Specs

Q: Is there a general grip size used for stating specs on new racquets? I’m starting to receive some new frames from Wilson and it appears as though the specs quoted for unstrung racquets were done for a 4-3/8” grip. My new nPro Surge was right on the money and it has a 4-3/8” grip. However, the nTour is a 4-1/2” grip and it differs. Are the specs posted on your site taken directly from the manufacturer? When manufacturers are giving swingweight measurements is each using the same apparatus (such as the Babolat Racquet Diagnostic Center) for the measurement? What do they use for measuring stiffness?

There’s a lot of confusion out here as to the consistency of information from various manufacturers. For instance, I’d like to be able to access the database at RacquetTECH.com and use comparison figures for racquets. If I know that the manufacturers are using a specific piece of equipment for measuring swingweight then I can re-calibrate my Rossignol Swingtest to match that piece of equipment. That way, when I have a customer come in with an older model frame that’s not in your database, I can do my own swingweight test and get a numeric figure to plug into the search feature when I’m trying to find my customer a close match to their current racquet.

A: All specs are taken from actual racquets, which are represented to us as being samples of production racquets. They are typically size 3 grips (4-3/8”), and each racquet is measured strung. We virtually never publish manufacturer specs.

We weigh each racquet on a calibrated scale, measure the balance on an Alpha Viper Balance Beam, and get the flex and swingweight from our Babolat RDC. From what we can gather, some manufacturers do use the Babolat RDC, but others have made their own equipment, and typically these custom measuring devices are significantly different from the Babolat RDC.

Although superficially similar to the swingweight portion of the Babolat RDC, the Rossignol swingweight tester produces results that cannot easily be correlated to those of the Babolat RDC because one reads low on the low end and high on the high end, compared to the other. We have tested swingweight using the pendulum method, however, and the data points correlate well with the RDC. (See our on-line tool at http://www.racquettech.com/members/ tools/swing_weight.html for all the details.) It is also worth noting that we sporadically check the calibration of the swingweight portion of our RDC using a special set of racquets having known measurements.

From the April 2005 issue
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