Playtest: Ashaway MonoGut ZX Pro
By Greg Raven
Ashaway MonoGut® ZX Pro is a monofilament string — like Ashaway MonoGut ZX — made from polyetheretherketone, a high temperature, engineering-grade polymer also known as PEEK and polyketone. The version used by Ashaway goes by the trade name Zyex®. Zyex molecules form complex chains with three aromatic bonds, compared to nylon with its simple covalent bonds that tend to break down, and polyester with its single aromatic bond. Ashaway claims that as a result of the better molecular bonding, MonoGut ZX Pro holds tension better, longer, and more consistently than other strings.
Ashaway tells us that the Zyex construction represents a revolution in monofilament technology, offering maximum comfort, gut-like playability, superior durability, and exceptional power for a monofilament — all with no polyester.
Ashaway’s target customers are players looking for a string that has the power and comfort of natural gut but with superior durability, at less than half the cost.
MonoGut ZX Pro is available in 1.22 mm in red or natural. It is priced from $14.25 for sets of 40 feet. 360-foot (110 meter) reels are available for $125, and 720-foot (220 meter) reels for $235.
For more information or to order, contact Ashaway at 800-556-7260, or visit ashawayusa.com. Be sure to read the conclusion for a special offer from Ashaway on MonoGut ZX Pro.
In the lab
The coil measured 40 feet. The diameter measured 1.21-1.24 mm prior to stringing, and 1.16-1.18 mm after stringing. We recorded a string bed stiffness of 76 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), string bed stiffness measured 69 RDC units, representing a 9 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. MonoGut ZX Pro added 15 grams to the weight of our unstrung frame.
The string was tested for five weeks by 33 USRSA testers, with NTRP ratings from 3.5 to 6.0. These are blind tests, with testers receiving unmarked strings in unmarked packages. Average number of hours tested was 27.
During installation, MonoGut ZX Pro seemed to have “anti-coil memory,” as it kept attempting to straighten out. Despite the thin gauge, it felt thick. With its smooth surface, crosses were easy to weave. Knots didn’t feel as though they are cinching down, but they weren’t loose. Overall, MonoGut ZX Pro is a great string to install. Ashaway recommends a 5 to 10 percent tension reduction compared to nylon, so we advised our testers accordingly.
Three testers broke the sample during stringing, five reported problems with coil memory, seven reported problems tying knots, and one reported friction burn.
On the court
MonoGut ZX Pro scored 8th best in the Power category of the 169 strings we’ve playtested to date, and 9th best in the Durability category. In addition, it was well above average in Resistance to Movement. As a result, MonoGut ZX Pro scored well above average overall.
Three testers broke the sample during the playtest period, one each at 4.5, 14, and 40 hours.
Synthetic strings that are said to play like natural gut are not new, but it’s not often that a manufacturer will make this claim about a monofilament. Ashaway has been working on developing Zyex strings for a long time now though, both with monofilaments such as MonoGut ZX Pro and with its famous Dynamite (tennis), PowerNick and UltraNick (squash), and UltraKill (racquetball) lines.
If MonoGut ZX Pro sounds interesting, Ashaway has a special offer for USRSA members: One set of MZX Pro Red and add two free sets for $20 (including delivery). All you need to do is prepay by check, Visa, or MasterCard before shipping.
“This string requires very little break-in time. The control is great, allowing for big swings without worry. The power is definitely there when it is needed. Excellent pop on groundies and serves.” 4.5 male baseliner with heavy spin using Babolat Pure Storm GT strung at 52 pounds CP (Tourna Big Hitter Blue 17)
“High marks for power and feel. Control is excellent.” 4.5 male all court player using Wilson Juice MP strung at 55 pounds CP (Wilson NXT 16)
“Impressive overall playability. Quite powerful with decent control and Incredible spin.” 4.0 male all court player using Head MicroGEL Prestige Pro Mid strung at 50 pounds LO (Gamma Professional 18)
“Great power on serves and overheads, to the point where I sometimes have to ‘throttle back.’ On ground strokes the control is so good that I can swing out with worry. String movement is a little high but there is no notching. Overall impression is very positive.” 5.0 male all court player using Babolat Pure Drive strung at 60 pounds CP (Babolat VS Touch 16)
“With a 5-10% tension reduction this string performs as well or better than my current natural gut hybrid. It seems to have the control and spin of a co-poly, but with more power. I don’t usually hit with a lot of spin, but the ball rotation I get with this is awesome. This string is also very accurate. I am surprised at the comfort as I expected it to be too stiff. It’s very friendly on the tendons. It also maintains tension remarkably well. I am not a string breaker but I suspect that this string would hold up very well against the competition. I would definitely consider buying it.” 4.0 male baseliner with moderate spin using Boris Becker Delta Core Sportster strung at 62 pounds LO (Volkl V Blast 17)
“Great tension maintenance. I hit some balls that seemed like they were going long, but the spin was so good that the ball came crashing down in the nick of time.” 5.0 male baseliner with heavy spin using Babolat Pure Storm Tour strung at 58/55 pounds CP (Babolat VS Touch/Babolat Pro Hurricane Tour 16/17)
“This string provides more spin than I typically get with polyester. It is one of the few monofilaments that I would switch to. I could easily recommend this to customers as a full bed, not just a hybrid.” 4.0 male baseliner with heavy spin using Dunlop 200G (Muscle Weave) strung at 50 pounds CP (Prince Synthetic Gut w/Duraflex 16)
“Massive spin! This monofilament has a very crisp response with no string movement. Zero soreness on the arm. Volleys feel firm.” 4 male all court player using Wilson BLX Pro Staff Six.One strung at 57 pounds LO (Wilson NXT 16)
“This string has great combination of durability and playability. After a short break-in period, comfort improves and is closer to that of a multifilament nylon.” 4.5 male serve-and-volley player using Dunlop Biomimetic 600 strung at 53 pounds LO (Gamma Live Wire 17)
“Playability, control, and comfort are all above average. Power and touch are also pretty good. Not quite as much bite as you get with textured strings.” 4.0 male all court player using Prince Triple Threat Viper strung at 60 pounds LO (Gamma Ruff 16)
“This is the best monofilament I have played to date. And my arm does not hurt! Nice zing on groundstrokes. While it doesn’t have quite the feel I like on volleys, the results are crisp and accurate. This string has good spin potential. I will definitely recommend it to my junior poly users.” 4.0 male touch player using Prince O3 Red MP strung at 55 pounds CP (Gamma TNT2 Pro Plus 17L)
“Not a personal favorite to string with but no big problems. This string produces very controlled groundstrokes. The is a nice ‘chip and charge’ string. It has good touch for drop shots along with very good spin and control.” 5.0 male baseliner with heavy spin using Babolat AeroPro Drive strung at 62 pounds CP (Babolat RPM Blast 16)
“Exceptional bite! This string allows me to hit extreme angles on cross court shots. Nice pop on serves with incredible accuracy. As a full setup, this one is a little firm on my aging shoulder, but I will definitely buy it for a hybrid.” 4.0 male all court player using Babolat Pure Drive strung at 46 pounds CP (Ytex Quadro Twist 17)
“In the hands of a more advanced player this string should provide plenty of power, spin and control.” 3.5 male all court player using Prince O3 Hybrid Shark OS strung at 50 pounds CP (Head FXP/Babolat Tonic+ 17/16)
“More power and spin than my typical setup. Great durability. Slightly lacking in control and touch.” 4.5 male serve-and-volley player using Wilson BLX Tempest Four strung at 60 pounds LO (Wilson NXT 16)
“The playability is great with a 15% tension reduction. For multifilament players I recommend reducing the tension by 10-15% rather than the recommended 5-10%. Unlike some poly-like strings, I would recommend this to all ability levels. Having just undergone shoulder surgery, it’s a little tough on the arm, but not bad.” 4.5 male all court player using Head Youtek Radical MP strung at 50 pounds LO (Babolat Xcel 16)
“The tension maintenance is exceptional. Playability stays constant throughout the test. It feels a tad firmer than a typical co-poly, with slightly less pocketing.” 5.0 male baseliner with heavy spin using Prince EXO3 Rebel strung at 52 pounds CP (Prince Beast XP 16)
“High marks for comfort and durability. This would make a great hybrid cross. It would also work well for less advanced players who place a premium on comfort.” 4.0 male all court player using Wilson BLX Pro Staff Six.One strung at 50 pounds CP (Tourna Big Hitter Black 7 17)
“After a break-in period with some minor tension loss, ball speed and comfort are good. This string should appeal to older players. It has above average playability, comfort and power.” 3.5 male touch player using Wilson nRage strung at 48 pounds CP (Prince Synthetic Gut w/Duraflex 17)
“This is a very comfortable string with excellent spin and power. It’s a little noisy on impact. Very resistant to notching. Overall, great feel and very soft on the arm.” 4.5 male all court player using Babolat Pure Drive Roddick + GT strung at 45 pounds CP (Weiss Cannon Black 5 Edge 16L)
“This is a good string for 3.5 to 4.5 level players. It’s quite durable. It would definitely add power to a hybrid. Overall, this a good string.” 4.5 male all court player using Wilson BLX Five strung at 60 pounds LO (Wilson NXT 16)
“I am not a huge fan of full bed poly, but this one is not overly harsh. It is ‘pingier’ than my typical setup. It’s almost like a comfortable co-poly. Groundstrokes have good spin but they are not as heavy as with my normal hybrid. Volleys are adequate but lack some touch. This is a decent string that produces the same results as a firm poly but without the break in period.” 5 male all court player using Prince EXO3 Rebel strung at 48 pounds CP (Prince Premier LT/Luxilon Ace 17/18)
“Comfortable! It starts to lose tension after about eight to ten hours. It has good spin but is not as crisp as my typical poly. Overall, the feel is average and there are no durability issues. Control and power are akin to what you would find with a lively co-poly.” 4.0 male all court player using Yonex RDS 003 strung at 57 pounds LO (Luxilon Savage 17)
“This string is ideal for players who want more power and spin. Durability is exceptional.” 5.0 male all court player using Wilson K Six One (16x18) strung at 56 pounds LO (Tecnifibre NRG2 16)
“This string is very durable. Resistance to movement is excellent. This is a very firm string that emits a buzzing sound on impact. I found touch and comfort to be lacking. It may work better in a hybrid setup.” 4.0 male all court player using Dunlop 200G (Muscle Weave) strung at 54 pounds CP (Tourna Big Hitter Black 7 17)
“This string piqued my interest while stringing. It stretches more than most polys as seems more vulnerable to installation variables like stringer technique and machine type. On the court it plays well but loses tension too quickly.” 5.0 male all court player using Prince EXO3 Tour (16x18) strung at 50 pounds LO (Prince Premier LT 16)
“This plays like an average 16 gauge poly. The feel is a little lacking. Power is above average.” 5.5 male all court player using Wilson BLX Six.One (16x18) strung at 50 pounds CP (Luxilon ALU Power/Natural Gut 16L/17)
“This string has nice feel, control, power, and spin in the beginning. With tension loss, however, control and feel suffer.” 3.5 male baseliner with heavy spin using Prince EXO3 Rebel strung at 52 pounds CP (Prince Beast XP/Prince Premier Attack 16/16)
“This string stretches more during installation than a normal poly. Coil memory is not as bad as with stiffer polys. In play this one errs on the side of control. It maintains tension through sixteen hours of play. Feel is slightly lacking and it makes a squeaking sound at impact. I would recommend this to someone who is a big string breaker.” 4.5 male all court player using Head Youtek Speed Elite strung at 55 pounds CP (Dunlop Black Widow 18)
“With a 5% tension reduction this string plays too powerful for me. Control is lacking. I did not notice any extra spin.” 4.0 male all court player using Pacific Raptor strung at 54 pounds LO (Pacific X Force/Pacific Power Line 18/16L)
“The sound is ‘tinny.’ The strings move a lot. The feel is okay and the durability is good. It has the playing characteristics of a poly, but the movement and tension loss of a synthetic gut. Weird.” 6.0 male all court player using Wilson BLX Juice strung at 52 pounds CP (Wilson NXT 16)
“I do not use a vibration dampener and so this string is too noisy. The noise is too distracting. I would not recommend this string.” 4.5 male all court player using Prince Original Graphite OS strung at 66 pounds LO (Polyester 17)
(Strings normally used by testers are indicated in parentheses.)
| EASE OF STRINGING
(compared to other strings)
|Number of testers who said it was:|
|about as easy||22|
|not quite as easy||7|
|not nearly as easy||1|
| OVERALL PLAYABILITY
(compared to the string played most often)
|Number of testers who said it was:|
|about as playable||5|
|not quite as playable||20|
|not nearly as playable||2|
| OVERALL DURABILITY
(compared to other strings of similar gauge)
|Number of testers who said it was:|
|about as durable||12|
|not quite as durable||2|
|not nearly as durable||0|
|From 1 to 5 (best)|
|Durability (9th overall)||4.4|
|Power (8th overall)||3.8|
|Resistance to Movement||3.7|
Zyex® is a trademark of Zyex Ltd.
See all articles by Greg Raven
About the Author
Greg Raven is an associate editor for Tennis Industry 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.
TI magazine search
TI magazine articles
- Our Serve: Eye on the Ball
- Industry News
- Racquet Tech: For Easy Grommet Installation, It’s About Finesse, Not Force
- Retailing 140: Understanding and Measuring Conversion
- Tennis Industry Hall of Fame: Peter Burwash Honored As Industry HOF Inductee
- US Open: Raising the Roof!
- Tennis Teaching Pros: Tennis Director of the Future
- The Passionate Player: The Tennis Congress Cure
- Grassroots Tennis: Play It Forward!