- RST X-4 S

First Impressions
The Roto Grip RST X-4 S presents itself as a striking addition to the popular RST series (Roto Star Tour), developed specifically for the international market and drawing wider attention since January 2024. Visually, the ball immediately stands out with its vibrant "Fuchsia / Deep Purple / Midnight" color scheme, which sets it clearly apart from the rather plain black of the regular RST X-4. Technically, Roto Grip relies on proven components here: inside works the asymmetric RST core, which already caused a stir in the original RST X-1. This core is characterized by a 2.53 RG and a 0.053 differential (at 15 lbs), giving it medium to high flare potential. The decisive feature of this model is the "Hyper X Pearl Reactive" coverstock. Unlike the often more aggressive MicroTrax blends, this cover is designed to store energy more efficiently through the heads. The factory 1500-grit polish underlines this approach and signals even before the first shot that this ball is meant to generate length. The combination of the torque-heavy core and the polished pearl cover promises a dynamic reaction as soon as the ball meets friction.
Comparison
Compared directly to the standard model, the RST X-4 by Roto Grip (which uses a MicroTrax Pearl cover), the RST X-4 S is designed to glide a bit "cleaner" through the heads. While the regular X-4 is meant to read somewhat earlier despite its pearl cover, the X-4 S with the Hyper X surface responds more readily to dry boards in the backend. In its philosophy it resembles the RST X-2 by Roto Grip, but the more modern coverstock technology gives it better reaction durability through the transition. Compared to current balls from other manufacturers, the RST X-4 S relates best to the Effect by Hammer or the Attention Star by Roto Grip. It offers more asymmetric torque than typical symmetric pearl balls, but is less "round" in its motion than, for example, a Summit Peak by Storm. It sits firmly in the "asymmetrical pearl" slot, where it delivers more definition at the breakpoint than pure control balls, but doesn't hook as early as balls with a solid surface (e.g. the RST X-4 Squad).
On the Lanes
The Roto Grip RST X-4 S is a classic "transition" ball for sport bowlers and an excellent option for house league bowlers on typical house shots. Its strength lies in the phase when the heads have already broken down a bit and solid-cover balls lose energy too early. Thanks to the polished surface, the X-4 S glides effortlessly through the first 15-20 feet and saves its rotation for the backend. If you like to open up the lane and play deeper angles, you'll appreciate the strong "skid-flip" character. As soon as the ball leaves the oil line and meets friction, the asymmetric core produces a quick change of direction and an aggressive entry into the pocket. This should provide improved carry, especially when you're forced to stand further left (as a right-hander) and throw to the right. It's less suited to fresh, very oily lanes ("heavy oil"), where it runs the risk of sliding past the breakpoint (blow-out), but it's ideal for medium conditions and lanes with defined friction on the outside.