Tennis Industry magazine


Playtest: Babolat M7 17

By Greg Raven

Babolat M7 is an innovative string with a new multifilament construction that provides power, comfort and durability. According to Babolat, the seven 100 percent polyamide monofilaments and innovative matrix of polyamide and polyurethane provide a longer lifespan and high level of comfort.

The manufacturer says M7 is for players who rarely break strings and are looking for power and comfort.

M7 is available in 16 and 17 gauges in Natural only. It is priced from $13 for 40-foot sets, and $189 for 660-foot (200-meter) reels. For more information or to order, contact Babolat at 877-316-9435, or visit

In the Lab

We tested the 17-gauge M7. The coil measured 40 feet. The diameter measured 1.27 mm prior to stringing, and 1.20 mm after stringing. We recorded a stringbed stiffness of 78 RDC units immediately after stringing at 60 pounds in a Wilson Pro Staff 6.1 95 (16 × 18 pattern) on a constant-pull machine.

After 24 hours (no playing), stringbed stiffness measured 71 RDC units, representing a 9 percent tension loss. Our control string, Prince Synthetic Gut Original 16 (Gold), measured 84 RDC units immediately after stringing and 77 RDC units after 24 hours, representing a 9 percent tension loss. In lab testing, Prince Synthetic Gut Original 16 (Gold) has a stiffness of 217 and a tension loss of 11.67 pounds, while Babolat M7 17 has a stiffness of 157 and a tension loss of 15.01 pounds. M7 17 added 13.9 grams to the weight of our unstrung frame.

The string was tested for five weeks by 36 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 17.4.

Out of the box, M7 feels to be a soft multifilament nylon with a polyurethane coating. Reinforcing this is the slight telltale polyurethane crunch during clamping. Our sample set felt thin, alerting us that we needed to adjust our clamps before starting installation.

No playtester broke the sample during stringing, one reported problems with coil memory, none reported problems tying knots, one reported friction burn, and none reported other problems.

On the Court

Our testers loved the Comfort of Babolat M7, rating it second only to natural gut in that category. They also rated M7 17th in the Power category and 20th in Touch/Feel. They found the Tension Retention to be well above average, and the Playability to be excellent.

Two playtesters reported premature fraying or peeling, one reported buzzing, and 15 reported notching.

Thirteen of the testers broke the sample during the playtest period, one each at 1, 2, 3, 3.5, 6, 7, 10, 15, 16, 17, 20, 25, and 30 hours.


Both the ratings and the comments from our playtest team agree that Babolat got both the comfort and power they were aiming for when designing M7, and there are plenty of players out there looking for a string with just these characteristics.

Playtester comments

“I really enjoyed this playtest. If you had a 6 available on the scale of 1-5 for touch, control, and feel, I would have given one. This is the most control I have ever experienced with this frame on groundstrokes and at the net. The only thing I could have asked for would be a little more bite on the ball. My test set seemed pretty slick and didn’t grab the ball as much as I would have hoped for with such a soft string. I will definitely carry this string and would be very open to switching to it myself.” 4.0 male all court player using Head Graphene Speed Pro strung at 45 pounds CP (Babolat N.Vy 17)

“I was worried this would play like a cheap nylon string, but was very surprised how wrong I was. It reminds me of a premium multifilament.” 4.0 male all court player using Babolat Pure Drive strung at 60 pounds CP (Luxilon ALU Power 16)

“Wow! This is a softer multifilament that is a true gem. My ability to hit finesse shots and power shots was incredible. For a player looking for comfort and not concerned about durability, this is their string!” 4.5 male all court player using Wilson Steam strung at 55 pounds CP (Luxilon 4G Rough/Wilson NXT 125/16)

“This was a very comfortable string that played well. This string provided great touch and feel and held its tension, which was a sign of high quality. What impressed me the most about this string was how soft and strong it was.” 4.5 male all court player using Wilson Blade 18x20 strung at 57/55 pounds LO (Babolat RPM Blast 16)

“This is a true player’s string. What you hit is what you get. This string provided the best feel, comfort, and control of any string that I have used in a long, long time. I will definitely use this string in the future.” 4.0 male baseliner with moderate spin using Wilson BLX Steam strung at 52 pounds CP (Wilson Sensation 17)

“A comfortable string with good crispness and power. Vibration kept to a minimum with nice touch. Reasonable spin and good control on serves. Easy to hit depth on ground strokes. An all-around playable string. I would like to know what it is, to carry it in my shop.” 4.5 male all court player using Wilson Steam S strung at 60 pounds CP (Gamma Solace 16)

“This string has lots of power! Highly recommended for players looking for a soft string that is easy on the arm and generates lots of power!” 3.5 male baseliner with heavy spin using Babolat Pure Drive Roddick strung at 63 pounds LO (Solinco Tour Bite 16L)

“A wonderfully comfortable string with a good amount of power.” 5.0 male all court player using Yonex Vcore si strung at 62 pounds CP (Head Hawk/Head Synthetic Gut PPS 18/16)

“I really liked it. Soft, forgiving string, good for control players who want some bite on their shots.” 5.0 male all court player using Babolat Pure Drive with Cortex strung at 40 pounds LO (Luxilon ALU Power/Wilson Synthetic Gut Extreme 16/16)

“The nexus between poly and nylons is getting closer and closer. This string did a very good job of offering the control of poly, and the playability of nylon. Good bite, good spin. Nice string for players wanting poly benefits but seeking some touch and feel as well.” 5.0 male all court player using Wilson Juice S strung at 59 pounds LO (Luxilon ALU Power/Wilson Sensation 16/16)

“It strung up nicely with no issues. The string had good feel and power. I am impressed with the durability of this multifilament string. It was a very comfortable string with no harsh shock. I would use this string as a main for a hybrid set up.” 3.5 male all court player using Dunlop iDapt 27.5 strung at 58.8 pounds CP (Wilson Sensation/Prince Synthetic Gut 17/18)

“Great comfort string. Very unique slippery surface. I would love the opportunity to string this in a hybrid!” 4.5 male touch player using Prince Tour T strung at 55 pounds CP (Genesis Black Magic 17)

“Great playing string, easy on the arm.” 4.5 male all court player using Babolat Pure Drive strung at 60 pounds CP (Babolat Origin 16)

“Fresh off the machine this string is very good. Excellent pop on the serve and good control on groundstrokes. I believe I should have strung this tighter by 2-3 pounds to offset the initial tension loss. I plan on getting more sets of this string and to offer it to my power touch customers. I can’t wait to find out who makes this string and how much it costs.” 3.5 male baseliner with moderate spin using Prince Speedport Black strung at 58 pounds CP (MSV Hex 19)

“For playability, this was one of the best nylon strings I’ve hit with. I enjoyed the control and comfort the strings provided, and the gut-like pop heard when hitting. I had better control on my backhand slice and volleys compared to my standard poly. Power was average in all respects (ground strokes, serves, etc.), but the ability to generate a lot of topspin was noticeably lacking. Even though the durability was weak for my game, I would highly recommend this string for regular synthetic gut players.” 5.0 male baseliner with heavy spin using Babolat Pure Storm GT Tour + strung at 56 pounds CP (Yonex Poly Pro Tour 16)

“This string seemed like another nylon string that is stiffer than your typical multifilament but more elastic than your typical polyester. Access to spin on this string was lacking and off center shots were accompanied by an unpleasant thud sound from the strings. Power, feel, and touch were very good. As a stiff polyester player, it did not take long to adjust to this string. Even though spin was lacking, I felt that the feel from this string compensated to allow my flatter shots to still find the court.” 5.0 male baseliner with heavy spin using Wilson BLX Pro Open strung at 60 pounds LO (Luxilon ALU Power 125)

“Very easy to string. Lubricated coating plus slight rough coating made for easy weaving. Very stretchy. Playing-wise, I had lots of power with this string. Good pop on the serve, volleys were good. A bit too much power from the baseline unless I put some spin on the ball.” 4.0 male all court player using Wilson Steam S strung at 60 pounds CP (Luxilon ALU Power/Gamma TNT2 16/16)

“String felt very lively for the first 10-15 hours. Good power, and spin potential. Lost significant tension before 20 hour mark.” 3.5 male baseliner with heavy spin using Prince O3 White strung at 58 pounds CP (Ytex Square X/Ytex Touch 16L/16)

“This string was stiff at 60 pounds. However, it has nice control. Great pop off the strings and lots of control. I believe if I had strung my racquet with less tension I would have rated the string higher. It didn’t seem to grab the ball like other strings I have tested. Overall I would say it is a good to very good string.” 5.5 male all court player using Babolat Pure Drive strung at 60 pounds CP (Babolat VS 16)

“The first thing I noticed is how easy on my arm it is. The power and feel due to its playability is great. If I were to try another coil I would string it at the higher end of my recommended string tension due to the initial first hour of tension loss. This would help on the groundstrokes resulting in more control. Overall, I would recommend this string to all playing levels except for string breakers.” 4.5 male serve-and-volley player using Head Graphene Radical strung at 56/58 pounds CP (Luxilon ALU Power Feel 18)

“A comfortable string with a fair amount of power. However, constant string movement necessitated straightening strings after each point. May be more appropriate to soften a poly-hybrid combo or for someone whose game does not revolve around spin. Not suggested for open patterned racquets as durability will suffer.” 4.0 male baseliner with heavy spin using Wilson Steam S strung at 56/54 pounds LO (Babolat Hurricane Feel/Wilson Revolve 16)

“This string played like an average nylon string. Performance was decent across the board, but never exceptional. I had trouble generating my usual spin with this string, which forced me to play more conservatively than usual. I’d say this string isn’t a good fit for a heavy baseliner game.” 4.0 male baseliner with heavy spin using Wilson Pro Staff Roger Federer strung at 55 pounds CP (Luxilon ALU Power Spin/Luxilon ALU Power Feel 16L/17)

“Although I generally liked the test string, I felt my consistency, and therefore control, suffered somewhat. Perhaps the fact that the mains had no ridges caused unwanted string movement and contributed to the perceived lack of control.” 4.0 male all court player using Head Prestige PWR strung at 52 pounds CP (Gamma Moto 17)

“This string was very soft to the feel right out of the package. It strung up very firm, however, which was very surprising to me. It has great feel and touch and, in addition, has more than adequate power. It is also an extremely comfortable string but it is not as durable as my own string of choice. I impart a fair amount of spin on the ball but I wouldn’t consider myself a ‘heavy’ topspin player. To this end, I felt like it moved considerably and not just over time. The strings moved all over the frame from first contact. This is a condition that I am not used to.” 4.5 male all court player using Head Graphene XT Instinct MP strung at 55 pounds CP (Tecnifibre Black Code/Tecnifibre NRG2 18/17)

“Stringmeter results came up with 55.5 pounds after playing, reference tension was 60 pounds. Overall, I found this to be a bit too powerful on groundstrokes. Great on baseline punch volleys and half volleys. Not much ability to create spin, especially while serving. There was visible notching on the mains after only six hours. Good on lobs to baseline. Impressive tension maintenance, but strings did move some in this 14 x 18 pattern frame.” 4.5 male all court player using Dunlop iDapt Force S strung at 60 pounds CP (Tecnifibre Pro Red Code/Gamma Synthetic Gut 1.20/1.30)

“The string was easy to put into the frame with no problems at all. It took a little bit of time for me to get used to the string behavior, but that is pretty standard. My first impression, after the break in period, was kind of a love/hate relationship; I liked the string at times but I also wanted to cut them out just as often. While I was teaching, the strings were fine, but when I used them to play practice matches the strings moved all over the place after a couple of sets. Giving the benefit of the doubt to the strings, they were played with on Har-Tru green clay surfaces, so the balls did get very heavy during play. Power was not difficult to generate, but spin was another issue all together. The string just did not bite the ball as I would have preferred. It did last longer than my normal strings, but I should have probably cut it out after the minimum 15 hours of use to save my arm from the fatigue that seemed to accompany every match I used it in during the test.” 4.5 male all court player using Babolat Aero Pro Drive strung at 57 pounds LO (Babolat RPM Blast/Tourna Quasi-Gut 16/16)

“A nice multifilament for folks with wrist, elbow, shoulder problems. When I first started using it, I couldn’t get nearly as much spin as my normal polyester string. But as I continued using the string, it felt fine and held tension surprisingly well. But it did break fairly soon.” 4.5 male all court player using Head Graphene Speed S strung at 56 pounds CP (Tourna Big Hitter Black 7 17)

“Good string. Very easy to install. Not crazy how fast the string notched after installation. Nice control, not much spin potential. Enjoyed the test.” 6.0 male all court player using Wilson Six One strung at 59 pounds CP (Wilson NXT 16)

“The string was easy to string but I miss the property of playing with poly. I didn’t feel I had as much control, power, or spin. After 5 hours of play the strings started to move and the string was showing signs of notching. If I had the opportunity to play a few more hours I am sure the strings would have broken. The only thing I liked about the strings was having a little more feel and comfort but I wouldn’t trade it for control or power.” 4.0 male all court player using Pro Kennex Kinetic Pro 7G strung at 60 pounds CP (Luxilon ALU Power 16)

“While the feel, comfort, and playability were nice, the strings moved as if they had been in the racquet for 2 years. Then they broke after 45 minutes of moderate hitting. This is the least durable string I’ve ever played with.” 4.5 male all court player using Prince Textreme Tour strung at 56 pounds CP (Prince Tour XC/Prince Premier Control 16L/16)

“The string appeared to be a multifilament string. It was comfortable but lacked power. I’m sorry, I wasn’t impressed with the string.” 4.5 male baseliner with moderate spin using Head Youtek Four Star strung at 57 pounds LO (Tier One T1 Firewire/Prince Lightning XX 17/16)

“As a nylon, this string lacked the character that has become the hallmark of co-poly strings. Used as a cross string in a blend it could be a possible choice. As an alternative to a co-poly this string has some potential. However the linchpin would be the price; too much (over $9 wholesale) would be a deal breaker. This string had a middle of the road feel but not anything that would make it stand out from the already crowded field.” 4.5 male all court player using Head Instinct MP strung at 50 pounds CP (Solinco Tour Bite Soft 17)

“I was not really impressed with the string. Playability was OK, but it lacked the feel.” 4.0 male all court player using Babolat Aero Pro Lite strung at 55 pounds CP (Solinco Tour Bite Soft 17)

“String played rather stiff at first considering it was not a poly. As it loosened up, I was not able to achieve as much spin. Strings moved all over the place after about an hour of play. It was fairly easy to string, but it just did not last long enough for my needs for me to consider purchasing this model.” 4.5 male baseliner with heavy spin using Head Graphene Speed Pro XT strung at 55 pounds CP (Head Gravity 17/18)

“I did not care for this string. It seemed very low powered; I just couldn’t seem to get any pop from it. This was far from the best multi I have played. It began to fray quickly. Now trying to say something positive, I would say the string is comfortable.” 3.5 male all court player using Wilson Blade strung at 58 pounds CP (Solinco Tour Bite/Gamma TNT2 17/17)

“Tension loss was apparent within the first 2 hours of play. Hard on the arm, and no control.” 4.0 female all court player using Babolat Pure Drive strung at 60 pounds CP (Natural Gut 17)

Playtester Ratings

EASE OF STRINGING (compared to other strings)
much easier 5
somewhat easier 18
about as easy 12
not quite as easy 1
not nearly as easy 0
OVERALL PLAYABILITY (compared to the string played most often)
much better 3
somewhat better 11
about as playable 6
not quite as playable 10
not nearly as playable 5
OVERALL DURABILITY (compared to other strings of similar gauge)
much better 0
somewhat better 4
about as durable 10
not quite as durable 14
not nearly as durable 7
From 1 to 5 (best)
Playability 3.7
Durability 2.7
Power (17th overall) 3.6
Control 3.3
Comfort (2nd overall) 4.2
Touch/Feel (20th overall) 3.6
Spin Potential 2.8
Holding Tension 3.4
Resistance to Movement 2.6

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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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