The D-Series motor is the most powerful member of the ancestor series, currently only for frames with normal dropouts. The BionX is the only motor in the test with four-stage recuperation (energy recovery); when the rear brake is applied, the motor switches to generator mode. This is very convenient, but does not replace the rear brake. However, this can increase the range by up to 15 per cent.
Due to its design, this hub motor has to contend with low speeds on steep sections and ramps due to its direct transmission, and its performance drops dramatically here. On steep cart tracks in the Alps, the motor comes to its knees and you have to use most of your own muscle power to pedal the 22 kilos up the mountain. We also had this problem during the test: the motor switched off a few times due to overheating. Not good: The battery mount is only fixed to the frame with two screws. As a result, the 3.2-kilo battery wobbled a lot.
Test summary of the Bionx D 250 DV
The Bionx D250 DV system leaves a somewhat mixed impression. It works well up to moderate inclines and on flat terrain. From around 8 km/h, the motor accelerates powerfully up to 27 km/h and is fun to ride. However, the design-related power deficit on steep ramps and motor shutdowns due to overheating are annoying. The battery mount seems undersized. More suitable for moderate tours.
Advantages and disadvantages
+ Silky-smooth response behaviour
+ Recuperation enables battery recharging
+ Good, clear display
- Vibrations occur from time to time
- High, unsprung mass on the rear wheel
- Quite weak in the low speed range
Technical data
Motor/position Rear wheel motor, 250 W
Max. Torque 50 NM
Tested battery Frame, 48 V, 8.8 Ah, Li-Ion, 423 Wh
Total weight approx. 4 kg motor, 3.2 kg battery
Functions Pedelec, push assistance, 4 support levels, recuperation
Installation by specialised dealer Yes
Range km/altitude approx. 100 km/1000 hm
Price 2099 Euro
Guarantee 3 years with annual inspection
Info www.ridebionx.com
