Playtest: Gamma RZR RX 16
By Greg Raven
Gamma RZR Rx is an oval-shaped co-extruded monofilament made of proprietary thermoplastic elastomer (TPE), a material that can be thought of as being halfway between plastic and rubber.
RZR Rx is like a composite polyester string but the TPE is engineered to stretch more upon impact for enhanced comfort and control. The TPE used in RZR Rx is more resilient than a typical polyester string. Thus RZR Rx transfers more energy to the ball and less impact to a player’s arm. The oval shape provides excellent spin for the baseline player. Gamma tells us that RZR Rx is designed for players who want the control and spin of a monofilament polyester string without the harshness and arm problems associated with the typical polyester string.
RZR RX is available in 16 and 17 gauges in black only. It is priced from $13.46 per set of 40 feet, $121.10 per 360-foot reel. For more information or to order, contact Gamma at 800-274-0317, or visit gammasports.com.
IN THE LAB
We tested the 16-gauge RZR RX. The coil measured 40 feet. The diameter measured 1.24-1.36 mm prior to stringing, and 1.19-1.25 mm after stringing, although at least some of this variation is due to the oval shape of RZR Rx. We recorded a stringbed stiffness of 77 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 a 10 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. In lab testing, Prince Synthetic Gut Original had a stiffness of 217 and a tension loss of 11.67 pounds, while Gamma RZR RX 16 had a stiffness of 217 and a tension loss of 15.7 pounds. RZR RX 16 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 26.9.
None of our playtesters mentioned noticing the shape of RZR Rx, but it is noticeable without changing the way you string. The biggest clue that there is something going on is that your clamps grab the string differently depending on whether you are clamping on the short axis, the long axis, or somewhere in between. RZR Rx also offers an intriguing clue about itself when you cut the end, as you can clearly see the light-colored core inside the black shell.
No playtester broke the sample during stringing, five reported problems with coil memory, three reported problems tying knots, three reported friction burn, and four reported other problems.
ON THE COURT
The extra flexibility of RZR Rx seemed not to detract from it in the Control or Spin Potential categories, as the members of our playtest team rated it 16th best of the 173 strings we’ve playtested to date for publication in each of these two polyester strongholds. However, our playtesters also rated RZR Rx excellent in the Playability category, which would be highly unusual for a poly. Our playtesters liked the balance of RZR RX, rating it well above average in the Durability, Tension Retention, Power, Comfort, and Touch/Feel categories.
One playtester reported premature fraying or peeling, none reported buzzing, and two reported notching.
Two playtesters broke the sample during the playtest period, one each at eight and 29 hours.
There seem to be a lot of players who really love certain aspects of traditional polys, although they have to forgo them because they need the softer feel of nylon strings. According to our playtesters, Gamma RZR Rx provides a string option for these “on the fence” players, without having to resort to hybrid stringing.
“Great overall playability for a poly. Nice crisp feel on volleys and overheads. Excellent feel and control from the baseline. Control on serves is especially good. As an older player who uses a multifilament, I am surprised by how little stress this polyester puts on my arm and wrist. This is a topnotch string.” 4.0 male all court player using Prince O3 Red MP strung at 54 pounds CP (Gamma TNT2 Pro Plus 17L)
“Outstanding comfort, feel and playability. Surprisingly good control for a soft string. The extra power on serves is a nightmare for my opponents.” 3.5 male all court player using Prince EXO3 Rebel strung at 63 pounds CP (Tourna Big Hitter Blue Rough 16)
“The spin and control are simply excellent. The overall playability is great with above average comfort and touch.” 5.0 male all court player using Head Youtek Graphene Speed PWR strung at 52 pounds CP (Gamma Zo black Ice 17)
“The soft response is immediately noticeable. This is a comfortable poly with great feel. It maintains tension better than any of the other strings I’ve tested. There is definitely some serious ‘snap back’ on impact. This string provides a nice combination of control and power on full swings. The three words that best describe this playtest are comfort, control, and power.” 5.5 male all court player using Babolat Pure Drive Cortex GT strung at 60 pounds CP (Babolat VS Team 17)
“This string plays softer than its peers. Great overall performance!” 3.5 male all court player using Pro Kennex Graphite Acclaim strung at 47 pounds CP (Head FXP/Babolat Tonic + 16/16)
“This is one of the best strings I have tested this year. It has great feel, control, and power. I would definitely buy it.” 4.5 male all court player using Wilson Steam 99S strung at 64 pounds LO (Luxilon 4G 16)
“Great feel and very easy access to spin!” 5.5 male all court player using Head Youtek IG Prestige MP strung at 58 pounds LO (Tecnifibre Black Code 16)
“The exceptional bite is apparent on topspin lobs where the ball comes down pretty sharply. This string has plenty of control for baseliners. It also has enough touch and feel for the doubles player who wants more playability at net.” 5.5 male all court player using Wilson BLX Pro Staff Six One strung at 49 pounds CP (Luxilon Alu Power/Pacific Tough Gut 16L/17)
“This poly has a great feel. Excellent comfort and touch, which is impressive for a firm string. Some string movement at the ten hour mark. I would definitely recommend this one to my customers.” 4.5 male baseliner with moderate spin using Wilson BLX Five strung at 60 pounds LO (Wilson NXT 17)
“Great bite for the topspin player, and very nice feel!” 4.0 male baseliner with heavy spin using Prince Triple Threat Hornet strung at 60 pounds CP (Tecnifibre Black Code 17)
“This is soft for a poly, and it has good feel. Good spin. I don’t typically use a full bed of poly, but I could use this one from time to time. I would recommend this someone trying poly for the first time. It is one of the best playing soft polys I’ve ever tried.” 5.0 male all court player using Wilson K Six One Tour strung at 60 pounds CP (Pro Supex Big Ace/Pro Supex Maxim Touch 18/17)
“I am surprised by how comfortable this poly plays. Even at lower tensions it has great control. String tension and playability hold up quite well with minimal notching. Overall, a very good soft poly.” 5.5 male all court player using Head Microgel Radical Pro MP strung at 55 pounds LO (Co-polyester 16)
“This is a comfortable high-performance polyester. It would be great in a thinner gauge, especially for players who want more playability but don’t need as much durability. Black seems to be in fashion, but this string could also find a niche with a varied assortment of colors.” 4.5 male baseliner with heavy spin using Head Youtek IG Instinct S strung at 58 pounds LO (Gamma Zo Verve 16)
“This string is soft with ample pocketing. The color eventually starts to wear off in high traffic areas. Tension drops after around ten hours of play. Great spin on kick serves and good feel on volleys. String movement is high, so I have to realign the mains often. Even so, this is definitely a comfortable poly with good spin and power.” 4.5 male all court player using Babolat Pure Drive Roddick GT strung at 45 pounds CP (WeissCannon Black 5 Edge 16)
“This string has noticeably more spin than my typical string, which is a multifilament. The durability is great, but there is some discoloration as the black color fades away in places. Though I am typically not a fan of polys because of their high stiffness, I do like the response of this string.” 4.5 male touch player using Wilson BLX Two strung at 63 pounds LO (Wilson NXT 16)
“For a firm string, performance is impressive. There is ample power without a corresponding loss of control.” 4.0 male all court player using Wilson BLX Pro Staff Six One strung at 50 pounds CP (Tourna Big Hitter Black 7 17)
“This is a very comfortable string with good control. High head speed is required to tap into the benefits. Even on my fastest swings the ball comes down reliably inside the lines. This string plays smooth but lacks pop. A nice riding sedan, not a race car.” 5.0 male all court player using Dunlop Biomimetic 300 Tour strung at 50 pounds CP (Dunlop Black Widow 18)
“Polyester is not usually to my liking, but this one plays comfortably with plenty of power. Control and durability are excellent. Tension stays pretty consistent. This string should have enough playability and comfort to suit different tastes and playing styles.” 4.5 male all court player using Head Youtek Radical MP strung at 55 pounds LO (Babolat Xcel 16)
“This is a good all around string with decent comfort, control, spin, and power. There is some string movement though.” 4.0 male all court player using Wilson nSix Two strung at 50 pounds CP (Tourna Big Hitter Black 7 16)
“A very decent poly. Good feel and control, especially at net. Power is moderate. No problems with tension maintenance or string movement.” 4.0 male baseliner with moderate spin using Babolat Pure Drive strung at 55 pounds CP (Babolat VS Touch 16)
“Feels a little stiff initially, but eventually relaxes and provides good pocketing and snap back. There is some notching by the second week. Good control.” 5.0 male all court player using Babolat Aero Storm Tour GT strung at 58/53 pounds CP (Babolat VS Team/Babolat RPM Dual 17/17)
“This string has good power, spin, and durability. Comfort is pretty good for a poly. Suffice it to say, polys have come a long way!” 4.0 male all court player using Head Flexpoint Prestige MP strung at 55 pounds LO (Gamma Professional 18)
“If priced as a premium poly, than this is not a great option. If priced as a ‘value poly,’ than this is a solid option. Coating is not overly slick, but spin is above average.” 5.0 male baseliner with moderate spin using Babolat Pure Storm Tour GT strung at 50 pounds CP (Babolat RPM Dual 17)
“This string gave me a bit more spin than I get from my typical setup. I find it average in most other areas.” 4.0 male baseliner with heavy spin using Dunlop 200G (Muscle Weave) strung at 50 pounds CP (Prince Synthetic Gut w/Duraflex 16)
“Holds tension well. Feels like a very responsive copolymer monofilament. Above average comfort and touch. The strings move a lot on spin shots.” 4.0 male all court player using Prince Triple Threat Viper strung at 60 pounds LO (Gamma Ruff 16)
“This string has a nice soft feel. However, after the second session of hard hitting, it loses too much tension. The control is fair and the spin is poor due to tension loss. This string is average in my opinion.” 6.0 male all court player using Wilson BLX Juice strung at 58 pounds CP (Luxilon 4G 16)
“The lack of touch makes volleys a little difficult. After adjusting to the low power level, my groundstrokes were quite accurate.” 3.5 male all court player using Babolat Pure Drive Cortex GT strung at 47 pounds CP (Ytex Quadro Twist )
“I found myself crushing this string too easily during installation. Loosening the clamps does not help very much as this results in too much slippage. In play, this string lacks the ‘wow’ factor. Playability and control are average.” 5.5 male all court player using Prince EXO 3 Tour (16×18) strung at 58 pounds LO (Polyester 16)
“There is some fraying and peeling during installation, but it doesn’t seem to get worse during play. Overall, the string has good power and control, but it does not have great spin, feel, or durability.” 4.0 male baseliner with heavy spin using Dunlop Biomimetic 500 Tour strung at 60 pounds LO (Luxilon Savage 16)
“This poly would work better in a hybrid.” 3.5 male all court player using Wilson nRage strung at 55 pounds CP (Gosen OG Sheep Micro 17)
“This is a springy poly which expectedly loses its fair share of tension. There is some color shedding. I enjoy playing with it as it has decent comfort and playability, but I think it would work better in a hybrid.” 4.5 male baseliner with heavy spin using Dunlop Biomimetic M2.0 strung at 57 pounds LO (Dunlop Black Widow 16)
“The strings move quite a bit. There is also a clicking sound on contact. After six hours the color starts to wear off, revealing a white spot in the stringbed. Overall, I am not pleased with the playability.” 4.5 male baseliner with heavy spin using Head Youtek IG Speed Elite strung at 52 pounds CP (Dunlop Black Widow 18)
“The only thing I like about this string is the control.” 4.5 male baseliner with heavy spin using Babolat Pure Storm Cortex GT strung at 55 pounds CP (Tourna Big Hitter Blue Rough 17)
| EASE OF STRINGING
(compared to other strings)
|Number of testers who said it was:|
|about as easy||21|
|not quite as easy||8|
|not nearly as easy||3|
| OVERALL PLAYABILITY
(compared to string played most often)
|Number of testers who said it was:|
|about as playable||7|
|not quite as playable||18|
|not nearly as playable||1|
| OVERALL DURABILITY
(compared to other strings of similar gauge)
|Number of testers who said it was:|
|about as durable||9|
|not quite as durable||5|
|not nearly as durable||0|
|From 1 to 5 (best)|
|Spin Potential (16th overall)||3.7|
|Resistance to Movement||3.4|
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 firstname.lastname@example.org, or through Facebook, LinkedIn, and Twitter. He plays tennis five days a week, and is turning into an avid cyclist.