10 days ago I went and strung up a couple of tennis rackets with Klip Legend 17g Natural Gut string at 58 pounds with a 15% pre-stretch. The rackets had been matched for weight and balance (each 366g, one balancing at 322mm and one at 324, which is closer than human perception can differentiate). An hour after coming off the machine both rackets were reading 55 pounds of tension from a hand-held gauge.
It was test time.
When I picked up the rackets from my stringer he very specifically did not tell me or intimate in any way which racket had been strung with our treated strings and which one had the standard strings. The rackets were simply labeled “1” and “2” (I put small stickers in the throats of all my rackets so that I know which of the matched sticks is which – it helps with spreading play around so that strings wear evenly and in knowing which racket is which if they were not all strung at the same time) and nothing about the two distinguished each from the other save the lead spread around the head of #1 (it was 8g lighter than #2 when I got it and had to be weighted and balanced to match exactly so that the test would isolate the difference of the string treatment).
I knew the lab tests on Babolat VS17 said that the treated string should have a softer stringbed on low-powered shots, so rapping the strings against the heal of my hand suggested that #2 might have the treated strings in it. But that was a wild guess at best. Only playing would tell if there was a difference that could be felt, and if so whether the difference was an improvement or a detriment.
Over the first 90 minutes of hitting it was instantly clear that there was a noticeable difference between the two sets of strings. # 1 felt more firm – though it was at the exact same tension as racket 2 when I picked them up minutes earlier – the response of the stringbed felt tighter. My shots seemed more precise and my control seemed better – like you would expect from a tighter string job. # 2 felt more plush – when I was just doddering around, lightly brushing up behind volleys and half volleys to make the die after the bounce Racket 2 just performed better. Both felt fantastic, like a player’s racket with Natural Gut strings should, and gave that satisfying Natural Gut POP with each ball strike.
One test session means both a great deal and very little. It was great to be able to instantly feel that there was a difference between the treated and untreated strings whichever they were. But I definitely needed more time to get to know the nuances of each setup and whether either really showed the characteristics that I was looking for based on the numbers I had seen from the lab tests.
I continued going out and hitting for the next 10 days – most of them anyway. Snow storms in Boulder slowed me down on a couple of occasions (but the underground parking at our office made a decent substitute for a court when the temperature was at least high enough that I didn’t think it would hurt the strings – natural gut is after all made from cow intestines, and the organic material and its collagen are more sensitive to temperature than synthetics). I kept putting in the time and making sure that I was taking note of the responses and sensations of the two rackets (or more specifically their stringjobs).
Since the test-rackets I was using were significantly more stiff than my typical Dunlop Max200g, I could say for certain that shock attenuation and comfort were imperceptibly similar for both – something that my buttery 200g might have camouflaged. And while my arm didn’t seem to distinguish between the two, my iPhone did. I had planned to check the tension at regular intervals using the rackettune app. The problem was that while I could get a nice reading on racket #2, it was virtually impossible on racket #1 for some reason (I had success 1 out of 22 attempts).
Since I couldn’t ‘cheat’ by testing the tension (I was certain that our process would improve tension maintenance, and that would be a pretty easy ‘tell’ so that I could zero-in on which racket had our strings in it) I had to really pay close attention to the feel I was getting. What showed up, more significantly as the test period progressed, was the dynamic stringbed response of racket #1. On shots where I needed more touch, where I might be cradling a volley over the net, the strings seemed to be more supple, and the sensation of the ball on the strings was better, by contrast racket #2 started out feeling buttery smooth an hour off the machine but from the second session onward that diminished. When I was hitting out, I had plenty of Natural Gut Power, but with a slight improvement in accuracy with #1 over #2.
For someone blind-testing a product, especially when that someone is part of the development team of that product, it’s unnerving to see performance changes like this. It means that either your process has durability (if #1 was had the treated strings), that it effects the very nature of the string and that a little bit of settling-in is all that is needed for it to be revealed; or that the benefits you thought you had gained were fleeting and that the rigors of time and use had flushed them out literally like field grass through a cow’s intestines (if #2 had the treated strings).
Finally, after 10 days in the rackets and with about 7 hours of play on each, today was the day that I was going to go in and get the string tension checked and find out which racket was strung with which string. Going in my guess (my hope) was that #1 had the treated string. When I heard the stringbed tension readings I was sure of it. #2 was checked first and came out at a consistent 50 pounds. #1 was at 52 pounds.
So there’s the first subjective test to confirm what our lab tests said. We have more stings that are off for lab testing now and more players who will be field-testing strings over the next couple weeks. At the moment I’m still excited…
