The Tretorn Series+ is an ITF (International Tennis Federation) approved tennis ball that is used at a number of ATP tournaments. The ball was known as the official ball for the ATP Challenger Series. The Tretorn Series+ tennis ball is built slightly differently than other tennis balls. This ball is made with the TRI-TEC system to maintain the pressure of the ball. This means that a membrane is placed around the rubber core of the ball, to ensure the optimal pressure for longer. Many gas-filled tennis balls do not last very long (they become soft quite quickly), this ball performs a lot better in that regard, but more about that later. The rubber core of the ball is slightly thinner than usual for optimal ball feel and also because the special membrane is placed over it. Finally, the felt layer. The Milliken felt is made for extra durability and thus a constant performance of the ball.
Review During 2 sessions (respectively 2.5 hours and 1.5 hours) on clay I put the Tretorn Serie+ tennis ball through the test. I must honestly admit that I was a bit sceptical at first because my previous encounters with Tretorn balls were the rather hard pressureless balls concerned the one I sometimes get to play during the competition. I'm not a big fan of that. But it soon became clear that this Tretorn Serie+ tennis ball is something completely different. Fresh from the box, the ball already has a whole nice feel. This remained the same during my 4 hours of play. With the Wilson US Open, where we play the competition and tournaments at our club, the ball fresh from the can still has to settle. I find that The ball then feels a bit light and floaty and I have the idea that I always have to put a bit more spin on my fairly flat groundstrokes to control the ball. After a set of play I find the Wilson US Open feels optimal, after which the ball lasts for about 5 hours in total before it is finished. The Wilson US Open does not excel in terms of durability. After 4 hours of play with this Tretorn Serie+ it looks still fresh enough for at least 4 hours extra. This ball definitely keeps the optimum pressure longer for longer playing pleasure. Compared to the Dunlop Fort Max TP that is also used for many tournaments in our area, I find the Tretorn Serie+ a bit more feel. The Fort Max TP from Dunlop feels a bit heavier. I think the balls don't differ much in terms of lifespan. I also tested the RS Allcourt Black Edition from RS Tennis (by Robin Söderling) earlier. In terms of feel, I think I find both balls comparable, where this Tretorn Serie+ ball plays a bit lighter. In terms of wear resistance, I find this Tretorn Serie+ ball, somewhat surprisingly, better. The Tretorn Serie+ gas-filled tennis ball has absolutely surprised me positively and I find it an excellent and more sustainable alternative for the Wilson US Open!