For the past 2 months Mike has been Retenser tested . With this gadget you can adjust the string tension of your racket on the court itself. Time for an extensive test!
What is the Retenser?
The Retenser is a Dutch invention and we can be proud of that! The Retenser is a device that you mount on the heart piece (the yoke) of the tennis racket, after you have first removed the grommet strip. The package consists of various parts: 2 plates (base), 1 cylinder holder, loose tubes with different shapes, a key and the cylinders. Depending on which version of the Retenser you have, there are 2 or 3. Then the 'building' begins.
First, place the tubings in the frame. The tubings have different numbers to 'run along' with the curvature of the yoke. Then you look for the most suitable mounting plate (base) of the 2. This depends on the curvature of the heart piece; this can differ per brand and/or model. Then you place the cylinder holder on the plate. The next step is to place the cylinders correctly on the holder. Then you can string the racket. There are 3 options for this. If you set the cylinders to 'minus', you can increase the string tension 2 times. In the 'plus' mode you can reduce the tension 2 times. In the neutral position you can increase the string tension 1 position and reduce the tension 1x. All cylinders must be in the same position when stringing.
This sounds complex and requires some 'practice'. Also, the Retenser does not (yet) fit every type of racket, especially rackets with the strings a bit wider apart in the heart piece, such as oversize rackets. I first tried the Retenser on my Diadem Elevate FS 98 , but unfortunately it didn't fit. Then I took the Head Graphene 360+ Gravity MP (prototype); the Retenser fitted without any problems.
However, something happens immediately with your racket: the total weight increased by 7.3 grams (316.3 grams without to 323.6 with Retenser), while the balance remained fairly the same (33.5 without and 33.6 with Retenser). However, this does result in a reasonable increase in swingweight (the mass you have to get around) with 6 points (319.5 without and 325.5 with Retenser). So you do change something in the specs and playing characteristics of the racket, this is good to know.
The Retenser on the track
I had the Gravity MP strung at 20 kg with the Diadem Flash 17 , good for a DT (Dynamic Tension) of 31. During my first session I played on a fast surface and the balls flew off my racket very easily, in short I could use some extra control. By adding tension, the DT went straight to 33, roughly 1 kg tighter. This was immediately noticeable. After scaling back to the neutral position, I then started to reduce the tension. This dropped the DT to 29, roughly 1 kg off the original 20 kg. So this also worked fine. In short: on the court this device does what it is supposed to do! The question remains how often you can do this. (Co)polyester strings have a limited stretch, a nylon, multi or gut of course much more. But the more often you do it, the less elastic the string will eventually become. And when stretching a string, it becomes thinner. But on the court the Retenser certainly does what it is supposed to do.
Bottom line
The Retenser is a fun and functional tool and does what it promises. The system is not yet mega user-friendly, although I understand that they are still working on it. I do wonder how long the device will last (how many stringings) and what target group the supplier has in mind with the Retenser. And by mounting the Retenser, something happens directly with the specifications and playing characteristics of the racket, which can be both positive and negative. All in all a very interesting test and let's see if we will see the Retenser a lot in the professional circuit!