Specialized e-bike motor in test: Specialized SL 1.2 motor for light e-MTBs

Alongside the Fazua Evation, the Specialized SL 1.1 is something like the forefather of light motors. With the introduction of the Specialised Levo SL Light e-MTBs became socially acceptable at the start of 2020. However, this was mainly due to the bike's great handling rather than the motor. The Specialized SL 1.1 was light and efficient, but also loud and not very powerful. Now the new Levo SL features the new Specialized SL 1.2 e-bike motor. With 50 Newton metres and 320 watts of power, it is said to offer 33 percent more power and 43 percent more torque than its predecessor. And thus make Specialized's light e-MTBs fit for the future when it comes to the motor.

The technical data: Specialised SL 1.2 e-bike motor

• Motor weight: 1.91 kg (EMTB measured value)
• Battery weight: 1.82 kg (320 Wh) (EMTB measured value)
• Battery options: 320 Wh; range extender: 160 Wh, 1.03 kg (EMTB measured value)
• Drive modes: Eco, Trail, Turbo, Infinite Tune
• Tightness: IP 67
• Connectivity: ANT+ (LEV)

The battery of the Specialized SL 1.2 motor for e-bikes

As with the SL 1.1, the Specialized SL 1.2 is only available in combination with a permanently installed 320 Wh battery. The battery cannot be removed for charging or changing on tour. A range extender in water bottle format is available to increase the range. The 160 extra watt hours weigh just over a kilo and fit easily into smaller rucksacks. The drive is installed in the new Trail bike Specialized Levo SL. Whether a new Kenevo SL with the SL 1.2 e-bike motor is not yet known.

Driving feel and power delivery of the Specialised E-bike motor

The Specialized system is one of the more minimalist drive systems in the light segment. This is also noticeable in the riding experience. The Specialized SL 1.2 still lacks the wow effect that classic e-bike motors offer with their striking power. This is because the thrust of the motor is rather discreet, even with full support. However, it also depends on your perspective. If you're used to riding without a motor, you'll be surprised at how quickly the speed display reaches double digits on steep forest roads, even with the Specialized motor. Simply dropping your legs while the motor does all the work is not the intention of the Specialized SL drive.

Especially at low cadences, the SL 1.2 has a little less oomph than a classic E-drive or its competitors, such as the Shimano Ep8 RS and Fazua Ride 60. If you hit a counter-climb in the wrong gear, you can expect little thrust from the motor. However, the increased torque compared to its predecessor is clearly noticeable on the Specialized SL 1.2 and helps the new e-bike motor to be a little more confident when it comes to a high step or a nasty off-road edge. Even when the ground becomes rough and uneven, the SL 1.2 remains more in control. The new Specialized Light-Assist drive is on a par with the HPR50 from TQ and clearly above the level of the old Specialized SL 1. 1 or the minimalist drive from Maxon.

At a high cadence, the Specialized pushes hard, but always remains in a manageable range. As a result, the ride always feels very smooth and the uniform power delivery over the cadence is very pleasant away from technical climbs. The free travel on acceleration is relatively short. The SL 1.2 drive responds very directly to the pedalling impulse in almost all riding situations and is easy to modulate.

The Specialised SL 1.2 e-bike motor in laboratory test

The power of the Specialized e-bike motor is measurably higher than that of its predecessor. Our laboratory test showed a maximum output of 278 watts at the rear wheel. The maximum torque of 50 Newton metres is now also on a par with the factory specification of the TQ HPR50 and only slightly below the 60 Newton metres of an EP8 RS or Fazua. Still a strength of the Specialized SL 1.2 drivetrain: the power curve is very balanced. Only at very high cadences above 110 rpm does the power drop off.

Also clearly evident in the lab test: In the factory setting, the Light Assist motor reacts strongly to changes in pedalling frequency, while the rider's power has no influence on the motor's output. This means that in turbo mode, the SL 1.2 delivers its full power even with minimal pedalling impulse. However, if the rider accelerates more, the motor does not deliver any more power. If you want to, you can set this via the app and make full power available only at very high rider input.

The Specialised E-BikeMotor in continuous load operation

Continuous load is often a difficult issue for small and lightweight e-bike drives. Because if you want to squeeze as much power as possible out of a compact drive, you run the risk of having a problem with heat dissipation. As a result, the drive has to reduce its output, as we see with TQ and Bafang/Forestal had to experience. Very nice: Derating doesn't seem to be an issue at all with Specialized, even with increased power. The drive delivers its 278 watts continuously, even under adverse conditions. Even in our standardised test scenario, a climb under continuous full load, the Specialized E-drive never reached critical housing temperatures. The overall system with the 320 battery is designed to match the performance of the SL 1.2. And this is where the new Specialized drive unit scores another trump card. Despite the still low battery capacity, the Specialized system climbed around 1030 metres in altitude at maximum support. Only 20 metres less altitude than its predecessor, despite the increased power and thus also a higher average speed. It would therefore appear that the new e-bike motor has become even more efficient than its predecessor.

Specialised SL 1.2Noise development

Performance, riding feel, installation space: all of this was already fine with the first Specialized SL drive unit. On the other hand: Many found the background noise annoying. Even in Eco mode, the SL 1.1 hummed unpleasantly and audibly. The new drive has made a clear step forward here. Even under full load, the Specialized SL 1.2 is rather quiet for an e-bike motor, the low frequency and the even noise are pleasant. The Specialized is not quite as quiet as a Fazua or even a TQ, but even those who ride longer tours with medium support should hardly be bothered by the drive noise. From a practical point of view, this is perhaps the most relevant improvement over the previous motor.

The operating elements of the Specialised E-bike motor

This is how we imagine successful control elements! The controller is unobtrusive but easy to use. The small screen in the top tube looks really high-quality, can be customised with data fields and offers a wide range of functions. Nevertheless, you don't feel like you're cruising through the forest with an overloaded multimedia centre. In some data fields, the font is borderline small, but this can be easily solved via the app settings. The overall operation of the system is very intuitive and the integration is absolutely streamlined. The compact shifter on the handlebars is also unobtrusive, the buttons provide good haptic feedback and are ergonomically positioned on the grip. Overall, the controls make a very high-quality and sophisticated impression.

A particularly clever feature from Specialized: the Microtune function. It can be activated by pressing and holding the Plus button and works like a fourth support mode, except that the support can be precisely adjusted from 0 to 100 per cent in 10 per cent increments using the buttons. If you want to ride with a fitter bio-biker or an e-biker in eco mode, you can easily adjust the speed and support to suit your touring partner. No other manufacturer offers this!

The App Mission Control is a fairly comprehensive and comparatively sophisticated tool. In addition to useful fine-tuning of the three riding modes (various pre-sets can be saved), there are system updates, fault diagnostics, information on the system history and even smart power regulation. Specialized promises that the e-bike will select the level of assistance so that the battery is sufficient for the planned tour. It is also possible to link the motor support to the heart rate.

• Fine adjustment of the U-steps
• Updates for all drive components
• Tracking + smart battery management
• Updates, error analysis, system information

EMTB conclusion on the Specialized SL 1.2 e-bike motor

The Specialized system has always been light, easy to modulate and efficient. Thanks to the SL 1.2, there is now more power, more torque and, above all, a much more pleasant drivetrain noise without having to make any compromises. The intuitive controls and the extensive app of the Specialized system are still top class. The Mastermind display in particular continues to set a benchmark with its successful combination of stylish design, streamlined integration and wide range of functions.