KTM Macina Scarp SX PRIME with Bosch Performance upgrade

In mid-2025, Bosch announced an upgrade to their Performance Line SX motor series. Via a firmware update, the light e-bike drive unit now delivers a peak torque of 60 Nm instead of the previous 55 Nm. We had the opportunity to ride one of the first motors featuring this upgrade, and this is why the KTM Macina Scarp SX Prime has accompanied me since autumn through the Vienna Woods, across the hills south of Vienna and into the undulating countryside surrounding the city. No press launch, no event setup, no fair-weather guarantee – just honest after-work rides, long brisk group rides on weekends and those days when you wonder why you’re even getting on the bike at three degrees Celsius and in dense fog.

Tech Specs

A real asset is the Bosch Smart System in combination with the Flow app. Assistance modes can be customised via the app – from efficient to aggressive. Particularly on longer rides, it proved useful to dial things back slightly in order to mitigate range anxiety. Range indicator and ride data also provide a realistic estimate of remaining battery reserves. The integration of the System Controller into the top tube is well executed too. The minimalist LED display blends discreetly into the frame design while delivering all essential information on battery status and ride mode. In combination with the Mini Remote on the handlebar, the system can be operated quickly and intuitively without a big bulky display dominating the cockpit. This makes for a cleaner and more dynamic look than the oversized screens on some full-power e-MTBs. This is exactly how you’d imagine a modern light e-MTB: clean, functional, and distraction-free.

All things considered, the Bosch SX isn’t a motor designed for maximum range or brute power delivery, but for sporty riders looking for a lightweight e-bike that feels natural. And it excels precisely in this role.

What the Scarp SX Prime excels at, however, is ride quality. With 140 mm of travel and a lightweight carbon frame, it feels more like a sporty downcountry bike than a classic e-MTB. It displays its agility on flowing trails in the Vienna Woods. Quick direction changes, tight corners, wavy ground – the bike responds precisely and directly. At times, you almost forget there’s a motor on board. Compared to heavier full-power e-MTBs, the Scarp feels agile, almost playful. The suspension is sensitive without becoming spongy. It absorbs roots and small trail chatter while still offering sufficient support for an active riding style.

The mechanical Shimano XTR 12-speed drivetrain is superb: precise, crisp and reliable – even in mud and wintery conditions. Frankly, you don’t miss having electronic shifting here at all. XTR simply works. Period. No readjusting, no drama. Shimano’s XT four-piston brakes deliver consistently strong performance as well. Even on long descents in the southern Vienna Woods, the bite point remains stable. The 17-kilogram machine can be slowed down confidently at any time. No surprises, no fading – just reliable performance.

In dry conditions, the Maxxis Rekon tyres perform very well. They roll quickly, offer sufficient grip and match the bike’s sporty character perfectly – especially on forest roads and hard surface trails. Once conditions turn wet, sloppy or rooty, however, they reach their limits. In the course of late autumn and winter, it became clear that a deeper tread and grippier compound would make for a far more relaxed ride. Anyone planning to use the Scarp year round should consider an upgrade.

Visually, the Macina Scarp SX Prime stands out with clean frame lines and an uncluttered silhouette. Particularly striking is the placement of the rear shock within the top tube – integrated, yet present. This gives the bike distinctive, modern looks. The lockout lever, however, is a little awkward to reach, especially on the move. It requires to either get used to or to briefly focus on it. Painted in a fresh, gallant blue the bike looks top-notch and pleasantly stands out from the usual black and grey without being overly garish. A real eye-catcher – especially when the sun filters through the trees on the trail. The stem with its integrated cable routing may require getting used to in terms of looks. However, the system offers a convenient advantage: swapping the handlebar is quite quick and straightforward, without having to dismantle half the bike. Function is prioritised over clean looks – and implemented in a sensible way.

After Lukas completed his review, I also got to take a few laps and gather some impressions from my perspective:

The handling of the KTM clearly shows that such a light e-MTB is much closer to a non-motorized bike than a full e-MTB. It's much more nimble and agile than my e-bike with a CX Gen4, making it significantly more playful on the trail. The Bosch SX with all updates surely plays a crucial role in making it often feel like you're just very fit, rather than motorized.

In Turbo mode, you'd really need to compare it directly with a full-power MTB to notice the performance difference immediately. Even with a heavy camera backpack, I wouldn't miss the maximum power.

As for the battery, I imagine it's similar to electric cars: A smaller battery operates closer to its performance limit and thus depletes sooner in this range. In Eco and Tour modes, the battery remains relatively stable, but when switching to Turbo mode, you can literally watch the bars fade away.

I think a range extender would work wonders here - even psychologically.

From autumn 2025 to February 2026, I climbed lots of vertical metres on the Scarp SX Prime – and gained just as many insights. It is lightweight and powerful with premium specs and makes for a fun ride on trails. Motor, drivetrain and brakes all perform at the highest level. However, it does demand compromise – particularly when it comes to range. Two rides home with a run-down battery are hard to condone. Ultimately, it’s a bike for sporty riders who know exactly what they want: maximum trail performance at minimal weight – and who are willing to come to terms with a small battery. Those who are will be rewarded with an excellent light e-MTB. Riders to whom range is key may want to think bigger – or at least keep a close eye on the battery level indicator.