Playtest: Gamma Zo Dart
By Greg Raven
Gamma Zo Dart looks to be a monofilament string, but in fact is really comprised of a soft co-polyester base string into which are embedded six stiffer monofilaments.
The Zo high-energy polyester core is softer for greater feel and comfort. The six embedded monofilaments are ultra high molecular weight polyester, which are stiffer than the core poly for greater control and durability.
Zo Dart is designed for poly users who want something that is softer and easier on the arm and offers more feel but still provides plenty of spin and control.
Zo Dart is available in 16 and 17 in black or white. It is priced from $13.50 for sets of 40 feet, $121.50 for 360-foot reels. For more information or to order, contact Gamma at 800-333-0337, or visit gammasports.com. Be sure to read the conclusion for more information about getting a free set to try for yourself.
IN THE LAB
We tested the 17-gauge Zo Dart. The coil measured 40 feet. The diameter measured 1.25-1.26 mm prior to stringing, and 1.20-1.22 mm after stringing. We recorded a stringbed stiffness of 75 RDC units immediately after stringing at 60 pounds in a Wilson Pro Staff 6.1 95 (16 x 18 pattern) on a constant-pull machine.
After 24 hours (no playing), stringbed stiffness measured 69 RDC units, representing an 8 percent tension loss. Our control string, Prince Synthetic Gut Original Gold 16, measured 78 RDC units immediately after stringing and 71 RDC units after 24 hours, representing a 9 percent tension loss. Zo Dart added 16 grams to the weight of our unstrung frame.
The string was tested for five weeks by 33 USRSA playtesters, with NTRP ratings from 3.5 to 6.0. These are blind tests, with playtesters receiving unmarked strings in unmarked packages. Average number of hours playtested was 27.
The sample felt thicker than a 17-gauge string out of the package, but we had no problems installing it.
No playtester broke his sample during stringing, one reported problems with coil memory, none reported problems tying knots, and none reported friction burn.
ON THE COURT
Gamma Zo Dart scored well with our playtesters, claiming the eighth-best ranking for Resistance to Movement and the 13th-best ranking for Durability of the 167 strings we’ve playtested for publication. Our playtest team also adjudged Zo Dart excellent in Control and Spin Potential, and well above average in Power. Overall, Gamma Zo Dart’s ranking is well above average.
Two testers broke the sample during play, one at five hours and one at 17 hours.
Don’t be mislead into thinking this softer offering by Gamma isn’t worthy of consideration by those seeking traditional poly experience. Zo Dart scored highest in Resistance to Movement, Durability, Control, and Spin, four of the main characteristics players seek in a polyester string. Add to this Zo Dart’s high score in the Power category, and you’ve got yourself one potent poly.
If you think that Gamma Zo Dart might be for you, fill out the coupon to get a free set to try.
“This is a very user friendly poly. After a short break-in, these strings provide great comfort and easy depth. Most surprising is the response and feel at net. This is one I would definitely recommend highly to my customers.” 4.5 male server-and-volley player using Head Youtek Radical MP strung at 53 pounds CP (Gamma Asterisk Tour 17)
“High coil memory makes installation a little slower. It’s worth the effort though. This string has incredible bite. Topspin jumps off the stringbed and explodes off the court. Power is higher than usual for such a firm string. I have never had more control.” 4.5 male all court player using Babolat AeroPro Drive GT strung at 56 pounds LO (Babolat RPM Blast 17)
“I won a tournament using this string! The control and spin gave me tremendous confidence, especially under pressure.” 5.0 male all court player using Babolat Pure Drive Roddick + GT strung at 40 pounds CP (Polyester 16)
“Stringbed is quite firm. Slice and kick serves are great with this one. Little effort is required.” 4.0 male all court player using Volkl V1 Classic strung at 56 pounds CP (Wilson Hyperlast Spin 19)
“This is a very soft poly. Players who want the feel of a hybrid will love this.” 5.0 male server-and-volley player using Volkl Organix 8 strung at 60 pounds CP (Tecnifibre Black Code 18)
“My hitting partner noticed the extra spin and power on my ball. He asked that I put down the racquet and play with another string. Enough said.” 5.5 male all court player using Babolat Pure Drive strung at 50 pounds LO (Wilson Stamina 16)
“Solid feel and tons of spin. This is a great string for serving. I need a dampener to give it a more muted sound. I would definitely recommend it to my poly players.” 4.5 male baseliner with heavy spin using Wilson nPro strung at 55 pounds LO (Signum Pro Poly Plasma 18)
“Great durability and spin. The mains really snap back robustly after each shot. Plays a little too firm in the beginning, but it eventually softens up nicely. I would lower the tension next time to get the right feel.” 4.5 male all court player using Wilson Kobra Tour strung at 55 pounds CP (Luxilon Savage 17)
“This is a very good poly. Great bite. The comfort is quite high.” 4.5 male all court player using Wilson K Blade strung at 57 pounds LO (Wilson Enduro Pro 17)
“This string has some extra power, especially on serves and volleys. Groundies are the same as with my typical set-up, but serves and volleys are better!” 5.0 male all court player using Babolat Pure Drive Cortex strung at 60 pounds CP (Luxilon Alu Power 16)
“This is a softer feeling poly. The first few hours feel great. The comfort and spin are front and center. Hitting both topspin and flat strokes are very easy. This plays like a softer version of Babolat RPM Blast. After twenty five hours the spin goes down but control is still decent.” 3.5 male baseliner with moderate spin using Volkl Organix 8 (300g) strung at 44 pounds CP (Tourna Big Hitter Blue 17)
“Nice combination of power, spin and control. Excellent touch for a poly.” 4.0 male baseliner with heavy spin using Babolat Pure Drive Roddick strung at 60 pounds LO (Solinco Tour Bite 16)
“This is one of the best strings I’ve hit with. The comfort from the baseline on high pace exchanges is impressive. I’m able to reply to low slices with hard topspin shots that come down with ease. Volleys at net came off with sufficient depth and precision. My slice serve has never been more lethal. I would probably lower the tension just a tad in order to get more touch, but that is small complaint compared to the overall performance of this string.” 5.0 male all court player using Wilson BLX Juice strung at 55 pounds LO (Luxilon Original 16)
“Absorbs incoming power very well. Higher swing speeds work best with this string. For beginners with slower strokes, this is likely to feel boardy. “ 4.5 male all court player using Babolat Pure Drive Roddick strung at 47 pounds CP (Solinco Revolution 18)
“This string provides pop on serves. The exceptional spin makes it easy to land second serves in the box. Topspin groundies feel very precise. Flat strokes are more challenging.” 5.5 male all court player using Wilson K Six One (16x18) strung at 55 pounds CP (Tecnifibre NRG2 16)
“It is very easy to rip topspin with this string. The lack of feel and power made shorter strokes harder to execute.” 4.5 male all court player using Prince EX03 Rebel (hole inserts) strung at 52 pounds LO (Solinco Tour Bite/Prince Premier Attack 18/17)
“Excellent playability, spin, control and feel in the beginning. After the tension drops, so too do the playability and control.” 6.0 male all court player using Wilson BLX Juice strung at 55 pounds CP (Luxilon Alu Power 16)
“Power is low. Great option for poly players who don’t like it when their stringbed ‘bags out,’ loses playability, and gets prematurely soft or mushy. These strings hold tension well and remain firm. I do not prefer the boardy feel. Power is okay, but achieving consistent depth requires me to swing out of my shoes. Spin is not as good with such a smooth surface. This string has only lost 10% of its tension in six weeks. Wow!” 4.5 male all court player using Dunlop Aergogel 5 Hundred Tour strung at 52 pounds CP (Tecnifibre Red Code 18)
“Great tension maintenance. Very minimal string movement. This would add nice spin and control to a hybrid.” 4.0 male baseliner with moderate spin using Prince O3 Speedport Black (hole inserts) strung at 48 pounds CP (MSV Focus Hex 17L)
“This is a comfortable poly with a nice balance balance between control and power. There is a little pinging, even with a dampener. Excellent spin.” 4.0 male all court player using Wilson BLX Pro Open strung at 45 pounds CP (WeissCannon Black 5 Edge 16L)
“This is an extremely solid feeling string. Durability is the feature that shines brightest. A great option for chronic string breakers. Spin potential is not a strong suit. It may work better for flat hitters.” 4.0 male baseliner with heavy spin using Dunlop Aerogel 4D 1 Hundred strung at 40 pounds LO (Luxilon M2 Pro 16L)
“Power is high, but spin and playability are only average. I would probably string it tighter next time to get the feel of my usual setup, which is a little stiffer.” 4.0 male baseliner with heavy spin using Dunlop Biomimetic 500 Tour strung at 57 pounds LO (Luxilon Savage 17)
“This is a very firm string. The first two hours of play feel very boardy and lack power. Spin and control are good. Feel is not so great on touch shots, but is fine on groundies. By the fourth hour, the stringbed loosens a bit. After twelve hours, the string seems to go dead. The control and spin are the main stand outs.” 5.0 male baseliner with heavy spin using Yonex V Core 98D strung at 60/57 pounds CP (Tecnifibre X One Biphase 17)
“Very firm and durable. Might not have enough feel for some players. Those who typically play with polyester should discover some extra power with this one. Depth comes easily. The extra bite is noticeable. Only a 4% tension loss after the first 24 hours. After 1.5 weeks with several sessions of hard hitting, tension loss was 16%. Tension remained steady thereafter.” 4.0 male all court player using Head MicroGEL Prestige MP strung at 55/57 pounds CP (Mantis Power Synthetic 17)
“This string allows me to blast away from the baseline. My spin is heavier. The feel and power were on the dead side. It plays a little loud.” 4.0 male all court player using Wilson BLX Steam strung at 52 pounds CP (Luxilon Alu Power 16L)
“Quite firm. For non poly players, this is probably best used in a hybrid or at the low end of the tension range. Control is good.” 4.o male server-and-volley player using Wilson Pro Staff 6.1 strung at 54 pounds LO (Wilson NXT 16)
“As multifilament nylon player, I prefer a softer response. Comfort and touch are lacking with this one. Durability is exceptional. Power is actually surprisingly high.” 5.0 male all court player using Wilson BLX Pro Staff Six One strung at 60 pounds LO (Wilson Hollow Core 16)
“Feels like a ‘middle of the road’ polyester. Comfort and control are above average, but the spin is not up there with some of the textured ones.” 4.0 male all court player using Volkl Power Bridge 1 strung at 56 pounds CP (Head Synthetic Gut PPS 17)
“Tension maintenance is good. The power is too low. Control is decent, but it’s hard to achieve depth when out of position. The feel is not sufficient for drop shots. This string reminds me of a first generation poly.” 4.5 male all court player using Pro Kennex Kinetic Pro 7g strung at 59 pounds CP (Luxilon Alu Power 16L)
“The power is perfect for players who require more control on big swings. It lacks the feel and touch for more compact strokes, especially for lesson feeds.” 4.5 male all court player using Wilson nSix One Tour strung at 50 pounds CP (Dunlop Black Widow 17)
“While this has all the standard poly attributes of control, spin, and durability, I prefer more touch and comfort.” 4.5 female all court player using Head Six Star strung at 58 pounds CP (Head Sonic Pro 17)
“Not enough feel, power, touch, or spin. This string doesn’t distinguish itself from the ever-growing crop of polys.” 4.0 male baseliner with moderate spin using Prince OZone Tour MP strung at 56 pounds CP (Polyester 17)
“Even with a 20% reduction in tension power is insufficient. This would be great for big hitters in search of more control. Not so good for beginners or intermediates with shorter strokes. I’m unable to get enough spin.” 4.0 male server-and-volley player using Prince EXO Graphite (port inserts) strung at 56 pounds CP (Wilson Sensation/Prince Synthetic Gut w/Duraflex 17/18)
| EASE OF STRINGING
(compared to other strings)
|Number of testers who said it was:|
|about as easy||17|
|not quite as easy||12|
|not nearly as easy||2|
| OVERALL PLAYABILITY
(compared to string played most often)
|Number of testers who said it was:|
|about as playable||8|
|not quite as playable||16|
|not nearly as playable||3|
| OVERALL DURABILITY
(compared to other strings of similar gauge)
|Number of testers who said it was:|
|about as durable||12|
|not quite as durable||1|
|not nearly as durable||0|
|From 1 to 5 (best)|
|Durability (13th overall)||4.4|
|Resistance to Movement (8th overall)||4.2|
See all articles by Greg Raven
About the Author
Greg Raven is an associate editor for RSI magazine and technical writer. He is certified as a Master Racquet Technician by the U.S. Racquet Stringers Association. He can be reached via e-mail at email@example.com, or through Facebook, LinkedIn, and Twitter. He plays tennis five days a week, and is turning into an avid cyclist.