Motors used by ebike producers belonging to the Derby Cycle group are branded “Impulse”; the most famous producers are Kalkhoff and Focus. Impulse motors are maybe less well-known than Bosch or Yamaha’s motors, but they’re just as good.
We had the chance to try the Impulse 2.0 motor on a high-end electric mountain bike. We were generally very positively impressed by the motor, though we also had some doubts about some specific aspects, as for instance the delay in reactivating the assistance after a gear change.
The Impulse system is different from the others because it was designed from an ebike producer, instead of them making an agreement with electric components producers like all the other ebike producers do (Bosch, Yamaha, Bafang and others don’t manufacture ebikes, but just the electric components which they supply to ebike producers).
The Impulse motor is a central motor that works directly on the transmission of the bike. A torque sensor and a cadence sensor regulate how much power is delivered: this makes the driving feel more natural. The choice of including high-capacity batteries is optimal and it’s also necessary if the motor is installed on an e-mtb.
For 2015 a new updated version of the Impulse system has been developed: it’s called the Impulse Evo. The new version is based on the Impulse 2.0 (that we tested), but many aspects have been improved.
The motor is more silent, thanks to the new materials used; it provides a maximum torque of 80Nm, which is higher than motors produced by Yamaha (70Nm) and Bosch (60Nm). A higher torque value allows the motor to deliver a higher power even at a low speed, which helps a lot on steep paths and when starting. It’s a very important feature in electric mountain bikes, while it’s not vital on city ebikes.
Reiner Kolberg, our friend and owner of e-bikeinfo.de tried the Impulse Evo and confirmed that the motor is very silent even when under stress. The influence of the cadence sensor on power delivery was modified, though we don’t have any more details about it. As it happens with Impulse 2.0, the Impulse Evo comes in three different versions: first of all there is a city version and a version more targeted at sports users (both of these with a European-style 25 km/h limit); and a version to be installed on S-Pedelec (a type of ebike very popular in Germany, Holland and Switzerland, with a maximum speed of 45 km/h).
Bosch chose to offer an advanced navigation system thanks to its new on-board computer Nyon: Impulse reacted to this move by integrating a new navigation system, even if it has a different mode of operation. The Nyon has a color screen and GPS sensors, the Impulse Evo navigation system is connected to and depends from a smartphone (connected via Bluetooth). The Impulse Evo display is monochrome and it tells you what direction to take and the distance from the next turn. You must use the Naviki app on your smartphone in order to use the navigation system. You can also charge your smartphone from the ebike battery : this is vital, as we all know how quickly your phone battery drains when using GPS.
Some of the design updates are also important: the battery is now completely integrated in the frame. Even so, the Impulse system maintains a battery with a capacity of 612Wh (the Bosch has only 400Wh) despite being integrated in the down tube of the frame. The aesthetic look is much better, especially if compared with the electric mountain bike we tried last year.
The Impulse Evo system is only available for some Kalkhoff ebikes at the moment, their Integrale and Include models. Both ebikes are designed for the city. The Integrale is the top of the range, with a sporty design (thanks to the integrated battery). The belt drive allows for more tidiness and it requires less maintenance.
The Include is targeted to women, also thanks to the shape of the step-through frame. The battery is integrated in the seat tube.
We have already got in touch with Kalkhoff: they will provide one of these bikes for us to try, as soon as they’ll be available in our country. The other brands under the Derby Cycle umbrella will keep using the Impulse 2.0; they will be able to implement the Impulse Evo from 2016 onwards. For more info about the Impulse Evo you can visit this page (only in German).