Courtesy of Head and the United States Racquet Stringers Association (USRSA), I received a sample pack of a new string from Head recently. Actually, Head Gravity is not a “new” string, per se, but a new combination of strings, which is what caught my attention. It is a pre-packaged “hybrid” that contains 22 feet of a 1.25mm (17 gauge) triangular co-polyester monofilament and 18 feet of a 1.20mm (18 gauge) traditional round co-polyester monofilament. (As the string lengths suggest, the triangular poly is designed for the mains and the round poly for the crosses — on only a few of the rackets I string could I do all of the mains with only 18 feet of string.) By the way,Head Gravity is reviewed in the February 2015 issue of Tennis Industry Magazine.
What caught my attention is that Head Gravity is a “poly-poly” hybrid. As I note on my “additional string information” page, hybrid stringing capitalizes on the strengths and minimize the weaknesses of different types of string. Typically, a hybrid string job will use a polyester monofilament on the main strings for firmness and durability, and a synthetic gut, multifilament, or natural gut on the cross strings for power and feel. These mains and crosses can also be reversed, though, for a different effect. Roger Federer and some others, for example, do use natural gut on the main strings and a monofilament on the cross strings for more feel and power — and obviously the reduced durability of a such a set-up is not an issue for Federer.
The fact that not all polyester monofilament strings are made the same makes the “poly-poly hybrid” a good option for those who want the durability of a monofilament string but a bit more “pop.” For example, with Wake Forest’s men’s tennis team, we have taken advantage of the range of Pacific’s monofilaments to provide the players with optimal poly-poly combinations. Pacific’s Poly Power Pro is one of the softest monofilaments we have found (stiffness rating of 222 according to the USRSA), and we hybrid it with Pacific’s stiffer Poly Force (294 stiffness) and X Cite (271 stiffness) strings. Because Poly Power Pro is a monofilament, we can use it as a main string for better feel and power without sacrificing much in the way of durability. This has been a popular option for players using rackets with 18 mains and 20 crosses (a tight string pattern), with 17 gauge Pacific Poly Force in the crosses. Poly Power Pro also makes a nice compliment in the cross strings when using Pacific X Cite in the mains.
When someone says “hybrid,” I do still think of someone who combines a monofilament string with a synthetic gun, multifilament, or gut, but Head’s Gravity reminds us that as monofilament technologies evolve, we should all consider the poly-poly hybrid as an option.