​KTM Macina Superbelt SX 10 Di2 (2027): Lightweight & featuring Alfine Di2 – a city e-bike reviewed

Anyone buying a city e-bike regularly faces the same trade-off: a bigger battery and a more powerful motor mean more weight, and more weight means a bike that’s harder to handle. The KTM Superbelt SX 10 Di2 resolves this conflict by clearly prioritising weight.

The 22 kg stated by the manufacturer is a low figure for a fully equipped city bike with mudguards, lights, a luggage rack and a kickstand – and a real advantage in everyday use when carrying, manoeuvring or parking the bike in tight spaces.

This comes at the cost of a smaller battery (400 Wh), a motor with lower torque and a reduced system weight limit of 140 kg. Anyone who is aware of and accepts these limitations will, in return, get a bike that handles noticeably more nimbly in urban traffic than heavier alternatives.

The electronic Shimano Alfine Di2 hub gear system (the mechanical 11-speed version is being tested here) is not something to be taken for granted in this price range and sets this model apart from the usual range of city bikes in technical terms.

Specifications: KTM Macina Superbelt SX 10 Di2 (2027)

Frame & suspension fork

The aluminium frame, made from 6061 alloy, is a trekking/on-road design specifically engineered for use with a belt drive. The split seat stay allows for the fitting and replacement of the Gates belt.

The geometry is designed for an upright, comfort-oriented ride: the low-riser handlebars (640 mm wide) and the stem with adjustable angle ensure a relaxed riding position in town.

The Suntour NCX32-D Sport Air suspension fork, with 63 mm of air travel and a 15×100 thru-axle, is the lighter and more responsive option compared to the coil-spring version. The lockout function allows the suspension to be locked out on smooth surfaces.

However, the entry-level fork does not offer any luxury features, such as damping adjustment. It is also the component that limits the maximum front brake disc size to 180 millimetres. In our view, that’s really the bare minimum for an e-bike that also has to carry shopping from time to time.

Motor: Bosch Performance SX instead of CX

The Bosch Performance SX (BDU3144) is not the most powerful option in the Bosch range – and that is by design. With now up to 60 Nm The torque of the small SX is significantly lower than that of the Performance CX, which now delivers twice the peak torque to the crankshaft.

The SX is lighter, more compact and offers an even more natural riding experience – the assistance feels less intrusive. Whilst this is sufficient for relaxed city riding on flat to gently undulating terrain, the motor reaches its limits sooner on longer climbs or when carrying heavier loads.

The system weight limit of 140 kg is correspondingly lower than that of CX-based models. Heavier people or users with a regularly loaded luggage rack should bear this in mind.

Battery and PTTL system

The Bosch CompactTube 400 Wh is significantly smaller than, for example, the 800 Wh version in the Macina City 820 XL Belt. This results in a significantly lower weight – and a correspondingly shorter range. For short everyday journeys and after-work rides, this isn’t a problem, but for longer trips, the capacity could become a limiting factor.

KTM has solved this using the PTTL (Power Tube Top Loader) concept: the battery can be removed from the frame via the top, making it possible to carry a spare battery. Suitable accessories – such as a saddle bag or a battery board for a rucksack – are available in the KTM range.

Alternatively, the Bosch PowerMore Range Extender (250 Wh) can be attached directly to the battery cover, which increases the total capacity to 650 Wh. This noticeably extends the range, but is an additional purchase that increases the total price and affects the driving experience.

Gear system: Shimano Alfine Di2 electronic

The most striking technical feature of this model is the Shimano Alfine Di2 in-hub gear system with eight speeds and electronic shifting, which, from 2027, will be controlled via the Shimano CUES Di2 EN605-R controller.

Electronic hub gears are still rare in the e-bike sector – the Di2 version shifts at the touch of a button, without a mechanical cable, and also allows for automatic shifting whilst stationary. The shifting is smooth and consistent, regardless of the current pedalling resistance.

Eight gears offer finer gear ratios than a five-speed Nexus derailleur – a noticeable advantage, particularly at the lower end of the gear range. Combined with the Gates CDC belt drive, this creates a system that is virtually maintenance-free: no oiling, no cable cables that stretch or get dirty.

The rear derailleur requires power from the drive battery – if the battery runs flat, it is possible to switch manually to an emergency mode, which will hopefully rarely be necessary.

Display & Operation: more Less

The Bosch Purion 200 is a compact, easy-to-read display with integrated controls. It is mounted on the handlebars next to the grip and displays key information – assistance level, speed, remaining battery capacity – but does not feature the colour display or connectivity functions of the KIOX 500. For a city bike designed for simplicity, this is a sensible choice; those looking for navigation support or smartphone connectivity will need to opt for a different display model or external solutions.

Brakes

The Shimano MT420-3A/MT410, with its two-piston technology, is not really adequately rated given the system’s weight limit of 140 kg. It seems that keeping the bike’s weight low took precedence over peace of mind and safety. Even though there are much heavier bikes out there, the KTM Macina Superbelt’s 22 kg weight does not make it a cross-country machine. Fitting larger brake discs is not an option, at least not with the Sunour NCX32 suspension fork, which allows a maximum of 180 mm.

Lighting and fittings

The Litemove RLX-100 front light, with 100 lux, is the brightest light when comparing the two bikes featured here. The downward beam pattern effectively illuminates the path ahead without dazzling oncoming traffic. At the rear is an AXA Juno – a functional, unobtrusive rear light.

The Schwalbe Marathon Mondial tyres (47-622) are slightly narrower than the Marathon E-Plus tyres fitted to the Macina City 820 XL Belt (50-622) and feature a RaceGuard puncture protection insert. The narrower profile suits the lighter overall design, but offers slightly less cushioning on rough surfaces. The Selle Royal Vaia Gel saddle takes on some of this role. The seatpost is a rigid design developed in-house by KTM – a suspension version like the bySchulz seatpost found on the heavier city model is not fitted here.

The KTM Alumee Snap-It 2.0 luggage rack is Monkeyload-compatible, but unlike the Macina City 820 XL Belt, it does not include the child seat option – which is in line with the lower system weight limit.

Weight

22 kg is an acceptable weight for a fully equipped city e-bike with mudguards, lights, a luggage rack and a kickstand. The difference compared with other affordable city e-bikes is sometimes several kilos – something that is clearly noticeable in everyday use when carrying, manoeuvring and parking the bike. The lighter motor, the smaller battery and the components designed for a lighter weight all contribute to this figure.

Our assessment

The Macina Superbelt SX 10 Di2 is based on a clearly defined concept: lightweight, low-maintenance and comfortable, without compromising on maximum range or motor power. The combination of the Bosch Performance SX, Shimano Alfine Di2 and Gates CDC belt is technically sound and performs well on flat urban terrain and moderate hills. Anyone needing stronger assistance, a higher system weight limit or greater battery capacity would be better off with the more powerful Macina City 820 XL Belt.

The extra cost of the Di2 electronics is well justified on this model: electronic hub gears shift more precisely, are more convenient to use and require less maintenance than mechanical versions – and are in keeping with the bike’s overall standards. The 400 Wh battery capacity is sufficient for short distances, but should be assessed realistically when deciding which bike to buy. Anyone who regularly cycles longer distances should factor in the range extender option or consider a model with a larger battery from the outset.

For 3,799 euros, you get a lightweight, well-equipped bike for everyday use – provided that the range of the compact battery suits your riding habits.