Tennis Industry magazine


Playtest: Yonex PolyTour Spin G 125

By Greg Raven

Yonex PolyTour Spin G is a durability-oriented high polymer polyester monofilament. Yonex refers to PolyTour Spin G’s five-sided cross-section as its Giga Spin structure. The material is treated using Yonex’s Silicone oil Infused Filament (SIF) process, which is said to increase the string’s snapback after deflection.

According to Yonex, PolyTour Spin G is designed to be stiff to allow players to hit out, while putting less stress on the elbow and wrist. The pentagonal shape enables heavy spin. In conjunction with the SIF, Yonex’s research shows improvements in both the amount of snapback and the speed of snapback.

Yonex designed PolyTour Spin G to give hard-hitting intermediate and advanced male players the heavy spin they want.

PolyTour Spin G is available in 1.25mm (16L gauge) in dark red only. It is priced from $15 for 12-meter (39-foot) sets, and $195 for 200-meter (656-foot) reels. For more information or to order, contact Yonex at 800-44-YONEX, or visit

In the Lab

The coil measured 42 feet, 3 inches. The diameter measured 1.26 mm prior to stringing, and 1.25 mm after stringing. We recorded a string-bed stiffness of 74 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 7 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 has a stiffness of 217 and a tension loss of 11.67 pounds, while Yonex PolyTour Spin G has a stiffness of 212 and a tension loss of 15.41 pounds. PolyTour Spin G added 16.3 grams to the weight of our unstrung frame.

The string was tested for five weeks by 38 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 27.7.

You can tell as soon as you take PolyTour Spin G out of the package that it’s a geometric, both by the feel and by the way the light reflects off of it. PolyTour Spin G is a bit unruly during stringing, and feels stiff, even to the point of having to pay attention when pulling the loops closed on knots. The corners of the string seem to be somewhat rounded, as the mains and crosses do not shave each other when installing the crosses. Some of our playtesters noted how nice the deep red of the string looks on red racquets.

One playtester broke the sample during stringing, six reported problems with coil memory, seven reported problems tying knots, none reported friction burn, and eight reported other problems.

On the Court

Living up to its promise, PolyTour Spin G received its best score in the Spin Potential category, where our playtesters awarded it excellent ratings. Our team also rated PolyTour Spin G well above average in Durability, Resistance to Movement, Playability, and Tension Retention. Overall, Yonex PolyTour Spin G came in well above average of the 184 strings that we’ve playtested for publication to date.

No playtesters reported premature fraying or peeling, one reported buzzing, and six reported notching. Four playtesters broke the sample during the playtest period, one at two hours, two at 20 hours, and one at 45 hours.


Yonex hit its marks with PolyTour Spin G in the spin, snapback, and durability categories. As a bonus, although it feels stiff during installation, it has a soft feeling in play, as noted by several members of our playtest team. This is backed up by our lab test results, which show that PolyTour Spin G’s stiffness is on par with a typical nylon string.

Playtester comments

“I truly enjoyed testing this string. Stringing it was great, no major coiling or friction burn. I recommend stringing a little tighter than usual (3 pounds at least). Since string was quite lively while playing. I felt like the level of awareness as far as ball contact and brush increased significantly. I felt the ball on my racquet so well!! Loved the color too!” 5.0 male baseliner with moderate spin using Babolat Pure Drive Play strung at 40 pounds CP (Babolat RPM Blast 18)

“Overall, a really good string. Excellent for 4.0 players and above. Comfortable right from the start. Responsive to spin and good control.” 3.5 female all court player using Prince Premiere ESP strung at 58 pounds CP (Prince Tour XP 15L)

“The string tested was very stiff and although the recommended string tension reduction was 5-10%, I would suggest 10-20% reduction. String played very well over the test period with no sign of wear, shifting, tension reduction. If one likes consistency throughout the life of a tennis string, this would be a superior product. The string felt and played consistently through the test period. The color and sheen make the string very nice to look at in the racquet. An excellent string for both recreational and competitive players.” 4.0 male all court player using Head Youtek Radical MP strung at 50 pounds LO (Babolat Excel Premium 17)

“I enjoy the feel, comfort, and playability of a soft string. I felt this string had exceptional playability and durability. It didn’t have the comfort, touch, or feel I like in a string, but if I were going to change to a poly, I would absolutely consider playing with this string. Overall, I thought it was one of the better strings I have play tested.” 5.0 male all court player using Wilson Pro Staff strung at 52 pounds CP (Luxilon/Wilson NXT 18/17)

“A very crisp and responsive string. Did seem to lose tension. The string had plenty of bite spinning the serve and groundies. Had plenty of control on volleys and dropshots. One of the best strings I have tested in a while. I felt it tested very well on all shots and not abusive to my arm.” 5.0 male all court player using Wilson BLX Steam S strung at 55 pounds CP (Dunlop Black Widow 18)

“Loved the color of the string. I hope it’s available. Well above average on most categories. String did not move at all while playing. High marks for power, spin, and control. Enjoyed playing with this string very much.” 4.5 male all court player using Prince ESP 100T strung at 55/58 pounds LO (Prince Tour XP 17)

“I was very pleasantly surprised. This was an extremely solid feeling string as I assumed it would have the same poly/stiff feel, but it didn’t. There was quite a bit of control and feel with this string. Where I would normally prefer a hybrid combination, I could see myself just using this string in the whole racquet. I had much greater confidence in touch shots and placement. I would recommend this string highly either by itself or as a hybrid and another soft string combination. There was plenty of spin and power in the racquet as well. This is a solid string for those wanting durability without sacrificing comfort. I enjoyed this string very much and would probably look to adding it in our selection of string in our tennis shop.” 5.0 male serve-and-volley player using Wilson BLX Five strung at 56 pounds CP (Luxilon 4G/Wilson NXT 17/16)

“This was an overall excellent string in most categories. Stringing was very easy in that there tended to be less coil memory compared to strings of similar construction. Playability, control, touch, and feel were all very good, which when combined with the string’s ability to hold tension, resist movement, and great durability, make this an exceptional string. I would recommend this string for those players moving from a multifilament or other synthetic to a poly string as I am sure they would be very positively impressed with its superior playability and durability characteristics.” 4.5 male all court player using Prince O3 Blue strung at 55 pounds LO (Tecnifibre NRG2 18)

“Overall a good playing string. Like the response and comfort. Still had control on off-center hits but lost some power. Would use it to play with in competition.” 5.0 male all court player using Head Graphene Prestige strung at 60 pounds LO (Head Sonic Pro 16)

“Great playing string. Great feel, great spin, and easy on my arm. I must admit I thought after installing the string it would be stiff with no feel. Complete opposite! I really liked it and would play with it all the time!” 6.0 male all court player using Wilson Juice S strung at 55 pounds CP (Luxilon 4G 17)

“Easy to string. It lasted the entire test period. The feel of the string was one of my favorite of all my testing. I used it as my major teaching and playing racquet.” 4.0 male all court player using Wilson Steam S strung at 56 pounds CP (Wilson Spin Cycle 16)

“Comparable to other poly strings. Enjoyed the chance to play with it.” 5.0 male all court player using Head Prestige strung at 55 pounds LO (Prince Synthetic Gut 16)

“Nice poly. I am impressed with the touch. Not wild about the maroon color, but it ended up looking good and feeling good.” 5.0 male all court player using Yonex V Tour G 330 strung at 53 pounds CP (Natural Gut/Polyester 16/17)

“Pretty nice string. Had a softer feel for what I assume was a co-poly string. Unique color too. Not too many strings in that color.” 4.0 male all court player using Boris Becker Delta Core London MP strung at 46 pounds CP (Ytex Octotwist 16L)

“Although a stiff string, it was quite playable. Nice power and control on full strokes, crisp volleys, good spin on strokes and serve. I didn’t have the feel I like on half volleys and any off center hits went nowhere. My arm usually has trouble with polyester, but no pain through the test. I would definitely recommend this string to poly users or those who want to try it. Would install lower tension also.” 4.0 male all court player using Prince O3 Red strung at 55 pounds CP (Gamma TNT Pro Plus 17L)

“Felt softer than most poly strings, making it more comfortable and increasing spin potential. At the lower tension, gave good pop on the ball. Felt more round than shaped.” 4.5 male baseliner with heavy spin using Volkl Organix 9 strung at 53 pounds CP (Tecnifibre Black Code 17)

“The first aspect of this string that struck me, and persisted, was the comfort. Vibration and twang were reduced making for a smooth experience, even on hard shots. String did seem to kink more easily than my usual strings. Power and spin were good, but not above average by much.” 4.0 male baseliner with heavy spin using Babolat Pure Strike strung at 57 pounds LO (Luxilon Savage 17)

“Good, durable, softer poly. Nice choice for a hybrid, but the playability wasn’t good enough for a full bed. Having said that, the comfort level and the spin potential make this a good recommendation for someone looking to try poly for the first time. Great color for my 2014 Pro Staff 90.” 4.5 male all court player using Wilson Pro Staff strung at 55 pounds CP (Pro Supex Big Ace Micro/Volkl Classic Synthetic Gut 19/16)

“If you can be patient enough to get through stringing with this string, the end result is good. Three annoying issues with stringing; coil memory, string kinking, string breaks easily, especially after it gets bent. If you can make it through to a finished, strung racquet, then you reap the rewards. String is durable once you make it to a strung racquet. Strings don’t move at all, very good. Nice comfort and pocketing. Good spin and control, without feeling excessively dead. Not sure I would recommend this for customers due to the difficulty in stringing, however I would be happy to string it upon request.” 4.0 male all court player using Head IG Prestige Mid strung at 48 pounds LO (Gamma Professional 18)

“A bit softer than the usual poly. It had a bit more playability and comfort as well as power. I am not a huge poly fan, but I found I like this string, except for the color.” 4.0 male baseliner with moderate spin using Babolat Pure Drive strung at 55 pounds CP (Babolat VS Gut 17)

“I liked this string as it provided lots of control and spin. However despite reducing tension by 5 pounds from my normal tension of 63 pounds (7.9% reduction), this string seemed less powerful. I might have enjoyed it more, had I reduced tension an additional 2 pounds to 56 pounds (a reduction of 11.1%).” 4.0 male all court player using Pro Kennex Ki 15 PSE strung at 58 pounds CP (Pacific X-Force/Pacific Power Line 18/16)

“Good spin production when racquet speed was sufficient. String still felt similar near the end of playtest period. Overall good poly string!” 5.0 male serve-and-volley player using Head Extreme Pro strung at 55 pounds LO (Gamma Live Wire Pro 16)

“At first, I loved the deep red color. Hours 2-5 string play with decent control and power. Hours 6-16 got worse to the point of trampoline effect where as ball control was lost. I’d be interested in the string as a cross string.” 4.0 male all court player using Wilson nSix One (18x20) strung at 45 pounds LO (Tourna Black 7 17)

“Had good power and control and was surprised at its touch. While string didn’t break, it was notched more than expected. For a pearl coated string, it had a lot of spin potential. Strings were not affected by weather. We had lots of rain and frost during the test period. I also liked the color.” 3.5 male all court player using Babolat Pure Storm strung at 48 pounds CP (Gamma TNT2 18)

“Solid string with very good control, spin, and durability. I felt like I could take a big swing at the ball and not lose control while keeping the ball in the court. Power was average, so requires mid to fast swing to generate some extra pop. Serves were accurate but lacked pop compared to my normal string. Big swinging players would like this string, while touch players probably not.” 4.0 male all court player using Volkl Organix V1 Pro strung at 50 pounds CP (Tourna Big Hitter Black 7 17)

“Overall, a pretty good string. Decent spin, good control, not very powerful. Didn’t move much at all.” 4.5 male baseliner with heavy spin using Head Graphene Radical MP strung at 48 pounds CP (Ytex QuadroTwist 16L)

“This string did not distinguish itself from most available strings of this type. Wasn’t bad or excellent. Middle of the road performance.” 3.5 male all court player using Pro Kennex Acclaim strung at 50 pounds CP (Kevlar/Synthetic Gut 18)

“The string provided no power, spin, or control. My serve had noticeably decreased power and lacked spin. The only positive thing were slices and drop shots. This string is suitable for recreational play.” 4.5 male all court player using Babolat Aero Pro Drive GT strung at 55 pounds CP (Babolat RPM Blast 17)

“Another good string for hard hitters looking for power and control. I would not recommend this string for beginner to 3.0 players or for player looking for a comfortable string. Even at lower tensions, it might lead to joint issues.” 4.0 female all court player using Prince Warrior 100L ESP strung at 55 pounds CP (Tecnifibre 17)

“I felt the string lacked power, but playability was relatively good. Comfort and control were good. Spin and touch were not as good. I liked the tension retention (in 3 weeks of testing, lost only about 17.5%). I would recommend this string for overall playability, comfort, and control. Not so good for power, spin or touch. Seems durable but then again, I don’t usually break strings. A lot of coil memory, so I would recommend using two-piece stringing method.” 4.0 male baseliner with moderate spin using Prince O3 Hybrid Hornet OS strung at 57 pounds LO (Dunlop Silk 17)

“Holding tension was above average.” 3.5 male all court player using Wilson N Tour strung at 52 pounds CP (Wilson Sensation 17)

“An average playing poly string.” 4.5 male all court player using Babolat Aero Pro Drive strung at 55 pounds CP (Babolat Origin 17)

“The string was nice but lost feel after about 10 hours and felt dead. Felt shock up arm after that. When not dead, a good access to spin.” 4.5 male baseliner with heavy spin using Babolat Pure Storm Tour strung at 46/44 pounds LO (Dunlop Poly 16)

“Average polyester string, with good durability. Tension loss seemed excessive, even with installing it at 10% less than my normal 60 pounds tension with nylon string. Average power and control, but below average comfort, spin potential, and movement resistance.” 4.0 male all court player using Prince Triple Threat Viper strung at 60 pounds LO (Gamma Ruff 16)

“Though I didn’t have a lot of time with the string, it felt a little stiffer than the soft type of string I normally am accustomed to. Seemed to keep tension, but I noticed a little notching even though I only played a few hours with it, which was a surprise as I thought it would be a string with durability. I rated it about average with the little time I had a chance to test it but started to feel more comfortable at the end with the string than at the start.” 4.5 male serve-and-volley player using Wilson BLX Two strung at 63 pounds LO (Wilson NXT 16)

“Run-of-the mill poly.” 4.5 male all court player using Prince Tour strung at 50 pounds CP (Prince Premiere Tour 16)

“Great durability but average in most other aspects. This string would perform better on very hot days. Too stiff for average to lo temp days. Great for chronic string breakers but would blend it for others.” 4.0 male baseliner with heavy spin using Dunlop 200G strung at 57 pounds CP (Prince Synthetic Gut with Duraflex 17)

“Had no trouble stringing. While hitting indoors, string broke right in the center mains after only 2 hours.” 4.5 male all court player using Wilson BLX 5 strung at 56 pounds LO (Wilson NXT 17)

(Strings normally used by testers are indicated in parentheses.)

Playtester Ratings

Ease of Stringing (compared to other strings)
much easier 0
somewhat easier 3
about as easy 18
not quite as easy 15
not nearly as easy 2
Overall Playability (compared to the string played most often)
much better 1
somewhat better 7
about as playable 9
not quite as playable 16
not nearly as playable 3
Overall Durability (compared to other strings of similar gauge)
much better 6
somewhat better 10
about as durable 17
not quite as durable 3
not nearly as durable 0
Rating Averages
From 1 to 5 (best)
Playability 3.5
Durability 4.0
Power 3.4
Control 3.5
Comfort 3.2
Touch/Feel 3.1
Spin Potential 3.6
Holding Tension 3.4
Resistance to Movement 3.7

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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, or through Facebook, LinkedIn, and Twitter. He plays tennis three to five days a week, and is turning into an avid cyclist.



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