The two low-assist drives in our motor test follow the trend towards small, inconspicuous and reduced-power motors for lightweight pedelecs. Thanks to their reduced size, they are perfectly suited for filigree and stylish design bikes. Because the small low-assist motors consume less energy than the mid-motor behemoths from Bosch, Shimano and others, they require smaller batteries. This gives manufacturers a high degree of freedom for frame design. Both drives share a reduced power delivery and low weight. However, there are no more similarities.
First overview of the Specialized SL 1.1 and the Lemo Dual Mode Hub
The Specialized SL 1.1 is a small mid-motor. It was developed in close collaboration with the German automotive company Mahle. The development specifications and the motor control software come from Specialized. The motor is available in the same design for e-mountainbikes and lightweight everyday pedelecs, but with different motor control and performance characteristics. Our test drive does its job in a lightweight Vado SL 4.0 EQ all-rounder. The motor control is designed accordingly: The Specialized drive only develops a lot of thrust at high cadences and is therefore aimed at sporty cyclists.
The dual mode hub of the Lemo, a rear hub motor, has a completely different characteristic. Even at very low cadences, it delivers a lot of power and, above all, a lot of torque to the rear wheel. This makes it interesting for cyclists who primarily want to save energy when travelling and - for example in the city - have to pedal frequently. In addition, the motor provides constant assistance as soon as the crank turns - regardless of how hard or fast the rider pedals. This is not very intuitive, as it prevents effective control of the motor power via the pedalling force, as we know it from most pedelecs. A special feature of the Lemo drive is a freewheel that allows the rider to mechanically disengage the drive completely from the hub. The motor, which is decoupled from the hub, then no longer offers any resistance to the rider's pedalling power and rolls motor-free like an "organic bike".
Displays and power dispensers
Lemo also breaks with the current design trend towards battery integration: the battery is housed together with the necessary electronic components in a frame bag (Smartpack) behind the head tube. If the Lemo is to be used as a motorless bike, the bag can be removed quickly and easily. Specialized offers an additional battery for the bottle cage in addition to the standard battery with only 320 watt hours that is permanently installed in the frame. The displays on both models, on the other hand, are rather minimalist.
While the motor instrument of the SL 1.1 only needs a bar display for the battery charge level and assistance level, the instrument of the Dual Mode Hub uses a digital display to provide information on speed, assistance level and battery charge level, among other things. There are additional smartphone apps for both motors that significantly expand the range of functions of the drive systems. The Specialized app, for example, allows you to adjust the performance characteristics of the drive to your personal preferences within certain limits. The Lemo app can be used to activate or deactivate an immobiliser, record tours or locate the pedelec via GPS.
Specialised SL 1.1
The SL 1.1 is one of the few low-assist mid-drive motors on the market - the segment is mainly occupied by hub motors. The motor is clearly audible, but not unpleasantly loud. When you press the pedal, the drive takes just under a quarter of a turn to start up. This makes starting off on inclines more difficult.
Good: It stops immediately when you stop pedalling. With a maximum available power of just under 250 watts, it is one of the weaker drives in the low assist range. It is therefore primarily aimed at sporty riders who like to invest a lot of leg power themselves. However, the drive with medium leg power input gives the lightweight Vado SL sufficient thrust and dynamism.
The maximum motor power of the SL 1.1 (blue line) varies with the speed: the faster the crank turns, the higher the power output. The SL 1.1 develops its maximum output of around 250 watts at high cadences. It does not matter how hard the rider pedals. At low cadences, the power output increases barely noticeably with increased pedalling force. At low, still effectively usable pedal revolutions, the drive delivers around 150 watts. The motor develops its maximum torque of around 44 Nm (red line) on our test bench at a pedalling power of 140 watts and a low cadence. The power development thus supports the rider when starting off, but decreases significantly with a higher cadence.
Test bike with Specialized SL 1.1: The Specialized Vado SL 4.0 EQ
- Price: 3900 Euro
- Frame: Aluminium
- Motor/battery: Specialised SL 1.1/320 Wh
- Circuit: SRAM NX, 1x11; 44/ 11-42 t.
- Tyres: Nimbus II Sport Reflect, 700x38
- Weight: 15.0 kilos
Lemo Dual Mode Hub
The unique selling point of the Lemo Dual Mode Hub is that the drive Detachable freewheel on the rear wheel hub. The power connection of the hub motor can be completely separated from the rear wheel. The Lemo motor starts up promptly as soon as the rider steps on the pedals. However, it takes over a second to switch off when you stop pedalling. This requires some attention if you want to slow down. Its maximum output of around 340 watts allows fast and dynamic pedalling, especially at low pedalling frequencies. A feature that allows effortless pedalling. When travelling, the motor provides thrust as soon as the crank turns. It does not matter how fast or how hard the rider pedals.
Unlike the Specialized SL 1.1, Lemo's Dual Mode Hub delivers its maximum power even at very low cadences: the motor generates just under 350 watts at only 40 pedal revolutions per minute. Because the torque in this range is also very high at 80 Nm, traffic light starts are dynamic and even starting uphill requires little leg power. The faster the crank turns, the less power the motor delivers. The torque drops relatively sharply up to a cadence of around 60, but remains useably high up to around 90 pedal revolutions. This allows the Lemo Dual Mode to be used for energy-saving pedalling. The power can be easily adjusted to personal preferences using three support levels.
Test bike with Lemo Dual Mode Hub: The Lemo One
- Price: 1990 Euro
- Frame: Aluminium
- Motor/battery: Dual Mode Hub/540 Wh
- Circuit: Shimano Deore, 1x10; 38/ 11-42 t.
- Tyres: Innova 44-584
- Weight: Wheel/battery 15.9/19.0 kilos
This is how we tested
Driving test
Not everything that a drive can do can be measured on a test bench. How sensitively an engine reacts to pedal pressure and how strongly it accelerates can only be seen on a test drive. This also applies to response and cut-off behaviour. The drive must be controllable and start up as quickly as possible when travelling uphill. When you stop pedalling, the motor should switch off immediately and not push on.
Test bench test
We measured the maximum continuous power of the motors on our test bench. It varies to a greater or lesser extent depending on the pedalling frequency (cadence). Measurements were taken at 20 km/h and, depending on the gear gradation, with different cadences between around 30 and 95 pedal revolutions per minute. We simulated the rider's pedalling power with 100, 120, 140, 160 and 180 watts. The diagrams below show the power curve as a function of cadence and pedalling power. The motors develop maximum torque at different cadences. We measured it on the rear wheel at 100 watts (Lemo) or 140 watts (Specialised) pedalling power and 20 km/h in each case.
