Kirschbaum Spiky Black Shark String Review

Power - Score: 25

As a firm, pre-stretched poly based string, it is not surprising that Black Shark didn't provide much power to our team. This turned out to be great for Andy, whose fast strokes and powerful racquet didn't need any help. He said, "I found Black Shark to be a stiffer-feeling, control-oriented string with low power, which was the perfect complement to the racquets I got to try it in. It tamed the power and lively feel of the Prince TT Warrior MP, Head Youtek IG Extreme Pro 2.0 and Youtek Graphene Speed Pro, so that I could really swing out and maximize spin without losing control. In a smaller midsize racquet Black Shark might not have possessed enough pop for my liking, but in a more modern feeling racquet the power level was right on."

For Michelle, Black Shark offered exactly the kind of low-powered control her long, fast strokes need. She said, "I wouldn't say this string added any power to my game (which is a good thing), rather, the excellent control gave me the confidence to supply my own power. I liked how it blended my power with some serious spin. It felt really crisp, which improved the feel and also helped me adjust the power level. I never felt like I had to work hard to find pace because of how well this string complemented my strokes."

Spin - Score: 93

Black Shark not only received one of the top spin scores from our Tennis Warehouse string lab, but it also earned one of the highest spin scores from our playtest staff. Needless to say, Andy was more than a little impressed, saying, "The sharp edges and slick surface of Black Shark enabled it to really grab the ball and get it rotating with some serious RPMs as it left the stringbed. Its low power also allowed me to take a big cut at the ball with confidence, giving me even more spin. If you are a player who likes to hit heavy topspin from the baseline, this is a string for you!"

Even with her flat mechanics, the exceptional spin potential of Black Shark gave Michelle access to an expanded range of shots. She said, "Adding spin to my flat strokes was effortless. I hit my forehand pretty flat, but I was able to use the spin to keep my balls deep and in the court. I also utilized the spin on my backhand to throw in a higher change-up ball. When I first started using the string there were several times I was sure my balls were going out by a few inches, but they ended up staying right inside the line due to the extra spin and bite from the string. My kick and slice serves really benefited as well, and had extra movement on them when using Black Shark. I enjoyed getting free points off my kick serve, and I even used my kick as a first serve in doubles because it was more effective than my flat first serve."

Comfort - Score: 55

Unlike Kirschbaum's first generation polys, which are very firm, Black Shark is constructed with a slightly softer co-polymer blend. This helps explain why Andy had such a smooth ride. He said, "For as stiff and low powered as it is, I never found Black Shark to be uncomfortable on the arm. It possesses enough softer filaments to help dampen harsh vibrations, and I think the way it slides on itself also helps to relieve some of the discomfort."

Michelle has been known to string her stiff Babolat Pure Drive with a full bed of poly at max tension. For this reason it is not surprising that she found Black Shark comfortable. She said, "I like tight strings, and even when I upped the tension of the Black Shark it still felt really comfortable to me (I have a tendency to be immune to stiff, less comfortable setups, though). I played with it strung at 58 lbs and 60 lbs, and I had no issues with comfort or arm soreness. I found this to be a really comfortable string."

Control - Score: 83

With its low-powered response and tight grip on the ball, Black Shark gave our playtesters all the control they needed. Taking advantage of the incredible bite was Michelle, who was clearly impressed by how reliably the spin kept her shots inside the lines. She said, "The control was one of my favorite things about this string. Instead of muting my power, I felt like the control came with the addition of spin. It is exactly what I look for in a string, something that enhances my game a bit and adds some control to my game. I leave it to my strings to do a lot of the 'controlling' with the way I play. Again, I found this string helped keep balls in that I thought were going to go out. I could really feel the strings gripping the ball without having to put too much effort into adding spin to my shots."

"This string is all about control and spin!" said Andy, agreeing with Michelle. "The stiff, low-powered response means your precision will be spot on, so take aim on all your shots with confidence. With a stiffer string, the stringbed will not change as much at impact, meaning you will get a more true response as the ball leaves the strings, hence more control. Black Shark fits the bill!"

Playability Duration - Score: 85

Since it is pre-stretched at the factory, Black Shark should, in theory, hold its tension and playability a little longer. According to Andy, the theory works. He said, "I actually found Black Shark to have exceptional playability duration. I was able to test it in a number of different racquets, so at times it was sitting in a particular racquet upward of a few weeks. I found the playability to still be there when I picked up one of those racquets again after a couple weeks, and the tension hadn't changed a whole lot."

Michelle noticed some minor changes over time, but found the playability quite consistent. She said, "After two weeks I felt like I lost a negligible amount of tension (a couple pounds at most), but not enough to re-string and not enough to make a significant change in the way the strings played."

Overall - Score: 80

Scores

(Scores are determined by averaging individual play test scores)

Playtester String Setups

Review date: April 2013. If you found this review interesting or have further questions or comments please contact us.

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