For the past 2 months, Mike has been using the Retenser tested . With this gadget you can adjust the string tension of your racket on the court. So 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 first removing 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 'follow' the curve of the yoke. Then look for the most suitable mounting plate (base) of the 2. This depends on the roundness of the heart piece; this may differ per brand and/or model. Then place the cylinder holder on the plate. The next step is to place the cylinders correctly on the holder. Then you can start stringing 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 tension 2 times. In the neutral position you can increase the string tension 1 position and decrease the tension 1x. All cylinders must be in the same position when stringing.
This sounds complex and requires some practice. The Retenser also does not (yet) fit on every type of racket, especially rackets with the strings slightly wider apart in the heart piece, such as oversize rackets. I first tried the Retenser on my Diadem Elevate FS 98 , but unfortunately it did not fit. Then I grabbed the Head Graphene 360+ Gravity MP (prototype); the Retenser fitted here without any problems.
However, something immediately happens to your racket: the total weight increased by 7.3 grams (316.3 grams without to 323.6 with Retenser), while the balance has remained relatively the same (33.5 without and 33.6 with Retenser). However, this does result in a reasonable increase swingweight (the mass that you have to keep moving around) with 6 points (319.5 without and 325.5 with Retenser). So you do change the specs and playing characteristics of the racket, this is good to know.
The Retenser on the track
I had the Gravity MP stretched 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 1kg tighter. This was immediately noticeable. After scaling back to the neutral position, I then reduced the voltage. This dropped the DT to 29, roughly 1 kg off the original 20 kg. So this also worked fine. In short: this device does what it's supposed to do on the track! The question remains how often you can do this. (Co)polyester strings have a limited stretch, 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 stretched, a string becomes thinner. But on the track the Retenser certainly does what it's supposed to do.
Bottom line
The Retenser is a fun and functional tool and does what it promises. The system is not yet very user-friendly, although I understand that people are still working on this. I do wonder how long the device will last (how many stringing sessions) and which target group the supplier has in mind with the Retenser. And by installing the Retenser, something immediately happens to 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 a lot of the Retenser in the professional circuit!