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USRSA racquet measurements

Q: How does USRSA measure racquets?

A: USRSA requests that manufacturers send one production sample of each newly-introduced racquet. Typically, these arrive with a 4-3/8 inch grip size. If the racquet is unstrung, we string it on a constant-pull machine, using 16-gauge string, to the middle of the tension range before we take any measurements.

When taking measurements, USRSA uses calibrated instruments. Before weighing the racquet, we check the scale using a known 200-gram reference mass. For length we use a name-brand tape measure. For balance we use Alpha’s Viper Balance Beam, which we have checked to verify its accuracy. USRSA’s Babolat RDC machine, which is used to measure flex and swingweight, is also calibrated: flex using Babolat-supplied calibration springs (which also allow calibration of the stringbed stiffness measurements), and swingweight with specially-weighted calibration racquets. Once properly set, the Babolat RDC doesn’t normally lose calibration, but it can and does happen, so we check ours ocassionally.

After testing, some racquets are returned to the manufacturer, but the vast majority is stored in boxes, for easy reference should a question ever arise about a measurement or stringing instructions.

From the September 2005 issue
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