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Differential string tensions

Q: I have a customer who has requested that I string his racquet with the crosses two pounds lower than the mains. He says that he heard that this “locks in” the mains. I’ve never heard of this, have you?

A: Stringing the mains and crosses at different tensions is not new, and in fact, a quick check of the pro equipment logs we’ve published over the years (available on-line at www.RacquetTECH.com) shows that more and more of the pros are asking for differential tensioning. We’ve not heard, however, that lowering the tension on the crosses “locks in” the mains, and frankly, we’re skeptical of this claim. According to Babolat, the main strings are responsible for durability and spin, while the crosses are responsible for power and comfort. Reducing the reference tension on the crosses would thus increase power and improve comfort, and possibly increase spin potential. Because of the differences in string lengths between the mains and the crosses, dropping the reference tension on the crosses partially equalizes the installed tension of the crosses compared to the mains. Dropping the reference tension on the crosses also reduces the tension increase on the mains due to the weaving and tensioning of the crosses.

One thing to watch when dropping the tension of the crosses relative to the mains (or vice versa) is that you are changing the stress on the frame. Always measure the dimensions of the hoop before and after stringing to ensure that differential tensioning isn’t distorting the hoop.

We should mention that manufacturers require differential tensioning on some racquets, which are clearly demarked in the Stringer’s Digest.

From the November 2004 issue
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