Question of the Day: Increasing the Durability of Multifilament Strings
TENNIS.com gear editor Justin diFeliciantonio and his technical advisers answer your equipment questions each day. Click here to send in a question of your own.
What advice do you give to frequent string breakers? I play about six hours a week at a 4.0 level with a flat, semi-Western forehand and Eastern backhand. I break strings at least once in that time frame. Currently, I’m using Wilson NXT 17, a multifilament, and really like the feel. I’d rather not switch to a full stringbed of polyester; I know poly’s more durable, but I’ve heard that it’s stiffer. Still, restringing all the time is tiresome and expensive. What can I do to increase my string durability without completely sacrificing the feel I’ve come to love?—Ethan H.
Your predicament, Ethan, is tough but not uncommon. A number of players, like yourself, prefer NXT-like multifilaments to monofilaments (i.e., polyesters), in part because multifilaments are much more pliant and yield a softer feel on impact. But as you mention, there's a tradeoff: Multifilaments are more prone to fraying and breakage. This is certainly the case when used by players with longer, faster swings, which subject the strings to greater deals of stress.
(Note: As categories, multifilaments are also more powerful than monofilaments, in the sense that the former returns more energy to the ball upon impact. Monofilaments, however, generally have greater spin potential.)
So what to do for extra string endurance? Is it possible to increase durability without significantly altering feel? It is, to an extent, as detailed further below. But before broaching solutions, it’s important to determine why you’re breaking so many strings to begin with.
According to The Physics and Technology of Tennis, most strings break for one of two reasons. The first is mishitting the ball. As physicist Howard Brody writes, on mishits, especially near the tip or the sides of the frame, “the strings tend to stretch asymmetrically, and the percentage of string elongation on the frame side of the impact is much greater than a typical impact near the center of the head. This increases the tension in that short section of string a great deal, possibly well beyond the tensile strength limit of that string, so it breaks.” Ever framed a hard-hit serve and found that a string had popped up at 12 o’clock? Well, that’s what happened, the string encountered a load it couldn’t bear, and so it faltered under the pressure.
That said, not all strings pop due to mishits. A second reason for breakage is simple abrasion. “If a player hits with spin,” says Brody, “the mains saw back and forth on the crosses, notching the mains. This notching reduces the cross sectional area of the string capable of carrying a load, making it effectively a thinner, weaker string at the notch. When sufficient string has been sawed away”—the strings’ coating having worn down—“the remaining string cannot support the incremental tension induced by the impact of balls, so it fails.”
So here’s the question: Are your strings popping abruptly at the edges, or steadily molting closer to the frame’s center?
If the former, the most straightforward way to increase string durability is to stop mishitting the ball. Lessons from a certified teaching professional can help in this regard, as can routine eye exams. (I jest…) Some mishitting players also find they can prevent premature breakage by routinely replacing their racquets' grommets; indeed, after a racquet’s been restrung a number of times, the grommet holes can warp and sharpen, thus presenting a risk to the corresponding strings.
But if you are sawing through strings every six hours—and don’t want to purchase a stick with a more durable, 18x20 string pattern, if you haven’t already—consider the following advice, which I solicited from Greg Raven, a Master Racquet Technician with the U.S. Racquet Stringers’ Association. “Try cleaning your strings after play,” says Raven, “to get any abrasive grit out of the strings’ intersections. For more durability, change to a heavier-gauge string first, and then from a multifilament to a solid-core durability string. If none of these improves the situation, you’ll have to try strings that have at least some polyester in them, or go to a hybrid string bed with half polyester and half nylon.”
Toward this end, switching to Wilson NXT 16 might extend your strings’ life an hour or two without altering too much feel. But if you’re still struggling with durability despite a lower gauge, and if you're willing to experiment, consider NXT Control, which weaves polyester and nylon fibers together into a single string. It won’t play with nearly as soft or with as much oomph as regular NXT. But given that you can supply ample pop with your swings, NXT Control should offer you some additional durability without drastically changing the string’s playing characteristics (at least, as a fullbed of polyester would). (For more information on how to string Wilson NXT Control, click here.)
As always, if in doubt, talk to a certified racquet technician or knowledgeable tennis pro. They should be able to help you figure out other ways to improve your stringbed’s durability without killing its feel.