I have tried both models during the week-end, and also did some research...
Crank drive / Impulse 2
The crank drive "impulse 2" system from Kalkhoff is impressive: those bikes don't feel like electric moped, but just like normal bikes on steroids. The torque sensor measures how much effort is put into pedaling, and provides a proportional assistance. Therefore, pedaling is still very much required, even on the highest level of assistance. Those bikes are good for people looking to cycle (as opposed to an electric "scooter") and still have a workout, but who may want to increase the distance of their trips or have assistance during slopes etc.
I also tried the Bosch crank drive system (second generation), and I don't think there is a massive difference between the two, apart from the more limited battery capacity offered on the Bosch powered bikes, and the different display and settings.
Unlike the hub motor driven bikes, the crank drive is just using the normal components and transmission of a bike to provide assistance, and therefore leverages the mechanical gears selected by the rider. This means the range achieved by an identical battery can be higher on a crank driven bike.
The impulse 2 system contains a gear change detector, which will cut the motor for a fraction of a second to ease the gear change, and attempt to reduce strain on the chain.
The first generation Impulse system (or Bosch equivalent) didn't have this. The main drawback of a crank driven bike is the strain on the chain, given the high torque of the motor, with an increased risk of breaking the chain while being out, even with the new system.
Riding the bikes
Both bikes ride very well, with a comfortable upright sitting position, typical of hybrid frames. They are of course very heavy, compared to similar non-electric hybrid bikes, but probably on par with a heavy duty "Boris" London bike in term of weight. They can be ridden without power assistance, but probably not over a long distance, unless the terrain is very flat or there is "tail" wind.
There are three levels of assistance available: Eco, Sport, Power. Bike can also be used without assistance (but with display still on). There is also a walk mode (6Km/h).
On a flat road or tow path, the Eco mode can be usually good enough, for a rider in good condition eager to pedal the same way as a normal bike. The Eco mode probably cancels the additional weight of the bike, and a bit more.
Changing the assistance level is very easy using the separate back lit control on the handle (+/-), and can be done at any time. When starting from still, the bike seems to boost assistance until some speed is achieved.
Equipment
Both models are entry level in the Kalkhoff range, but still have a very good level of equipments.
Kalkhoff Pro Connect Impulse 9:
Kalkhoff Pro Connect Impulse 10:
They look like premium bikes, well made, apart from:
Kalkhoff does not publish the precise weight of their bikes, annoyingly. On the other hand, it probably does not make that much difference on an electric bike.
Battery and price
11.5Ah battery: 416Wh, 2.85kg. Range: probably 50-60 miles in Eco mode.
17Ah battery: 612Wh, 2.95kg. Range: probably at least 100 miles in Eco mode.
Unfortunately, the Impulse 9 is not available in the UK with a 14.5Ah battery upgrade/option, so the only 11.5Ah battery on offer would be quite limited if a high assistance level is required. Battery will also drop to 60% capacity after 1,000 full charges, and lose 5% capacity per year just during storage, so starting from a fairly low capacity will mean some range issues after a couple of years in normal usage.
Batteries are not subject to memory effect, so can be recharged in full without being discharged completely first.
For many people, it would be a good enough reason to go for the Impulse 10, given its massive 17Ah battery. The other equipment improvements of the Impulse 10 are welcome, but quite minor, and the 9 speed gears are probably sufficient for most people. Unfortunately, the price gap is a massive £700 between both bikes, which makes the battery upgrade very expensive.
The Impulse 9 is however competitively priced against other Bosch crank driven bikes, with similar "small" batteries, but is expensive compared to Chinese low end hub driven bikes, which wouldn't have the same quality or warranty, but typically much higher battery capacity.
Battery can be charged on the bike, or removed easily. Battery is secured to the frame with a lock/key. Battery contains a number of LED indicators and a button to also check the remaining power, and also overall capacity left/usage compared to new.
Electronic Display
Both bikes come with the entry level, Kalkhoff "compact display". The display shows the speed, assistance mode, battery capacity and trip/total mileage. It's really a shame that the display cannot be removed easily, when the bike is locked on the street for instance.
The compact display does not have other informations found on the "large display" (available on more expensive bikes), such as expected remaining range in miles, cost per trip, trip duration etc. The large display also offers the user the option to change many settings directly, such as the dynamic/normal assistance mode (in addition to other modes, makes the assistance more responsive and with more torque), the diameter of the wheels (which can influence the assisted top speed), the motor stop duration during gear shifts etc.
Those settings can still be changed on the Impulse 9 and 10, but would require a visit to the dealer, and the appropriate electronic hardware.
I think that, given the large price difference between the Impulse 9 and 10, the higher model should really have benefited from the upgraded display and settings.
Once I have received mine and done a few trips, I shall provide some further updates.
Crank drive / Impulse 2
The crank drive "impulse 2" system from Kalkhoff is impressive: those bikes don't feel like electric moped, but just like normal bikes on steroids. The torque sensor measures how much effort is put into pedaling, and provides a proportional assistance. Therefore, pedaling is still very much required, even on the highest level of assistance. Those bikes are good for people looking to cycle (as opposed to an electric "scooter") and still have a workout, but who may want to increase the distance of their trips or have assistance during slopes etc.
I also tried the Bosch crank drive system (second generation), and I don't think there is a massive difference between the two, apart from the more limited battery capacity offered on the Bosch powered bikes, and the different display and settings.
Unlike the hub motor driven bikes, the crank drive is just using the normal components and transmission of a bike to provide assistance, and therefore leverages the mechanical gears selected by the rider. This means the range achieved by an identical battery can be higher on a crank driven bike.
The impulse 2 system contains a gear change detector, which will cut the motor for a fraction of a second to ease the gear change, and attempt to reduce strain on the chain.
The first generation Impulse system (or Bosch equivalent) didn't have this. The main drawback of a crank driven bike is the strain on the chain, given the high torque of the motor, with an increased risk of breaking the chain while being out, even with the new system.
Riding the bikes
Both bikes ride very well, with a comfortable upright sitting position, typical of hybrid frames. They are of course very heavy, compared to similar non-electric hybrid bikes, but probably on par with a heavy duty "Boris" London bike in term of weight. They can be ridden without power assistance, but probably not over a long distance, unless the terrain is very flat or there is "tail" wind.
There are three levels of assistance available: Eco, Sport, Power. Bike can also be used without assistance (but with display still on). There is also a walk mode (6Km/h).
On a flat road or tow path, the Eco mode can be usually good enough, for a rider in good condition eager to pedal the same way as a normal bike. The Eco mode probably cancels the additional weight of the bike, and a bit more.
Changing the assistance level is very easy using the separate back lit control on the handle (+/-), and can be done at any time. When starting from still, the bike seems to boost assistance until some speed is achieved.
Equipment
Both models are entry level in the Kalkhoff range, but still have a very good level of equipments.
Kalkhoff Pro Connect Impulse 9:
- 9 gears
- 11.5 Ah battery
- Compact display
- Hydraulic brakes with disk (front and rear)
- Front suspension (non lockable)
Kalkhoff Pro Connect Impulse 10:
- 10 gears
- 17 Ah battery
- Compact display
- Front suspension (lockable)
- Various upgraded components (brakes, brighter 80 lux front light, seatpost, wheels etc)
- front and rear lights, powered by a hub dynamo, brake light
- mud guards
- luggage rack with spring clamp
- chain protection
- robust kickstand etc.
They look like premium bikes, well made, apart from:
- The bells provided are a bit strange, as the full bell is moving
- There is just a sticker on the battery to match the look and feel/decoration on the frames, and this looks average and cheap
Kalkhoff does not publish the precise weight of their bikes, annoyingly. On the other hand, it probably does not make that much difference on an electric bike.
Battery and price
11.5Ah battery: 416Wh, 2.85kg. Range: probably 50-60 miles in Eco mode.
17Ah battery: 612Wh, 2.95kg. Range: probably at least 100 miles in Eco mode.
Unfortunately, the Impulse 9 is not available in the UK with a 14.5Ah battery upgrade/option, so the only 11.5Ah battery on offer would be quite limited if a high assistance level is required. Battery will also drop to 60% capacity after 1,000 full charges, and lose 5% capacity per year just during storage, so starting from a fairly low capacity will mean some range issues after a couple of years in normal usage.
Batteries are not subject to memory effect, so can be recharged in full without being discharged completely first.
For many people, it would be a good enough reason to go for the Impulse 10, given its massive 17Ah battery. The other equipment improvements of the Impulse 10 are welcome, but quite minor, and the 9 speed gears are probably sufficient for most people. Unfortunately, the price gap is a massive £700 between both bikes, which makes the battery upgrade very expensive.
The Impulse 9 is however competitively priced against other Bosch crank driven bikes, with similar "small" batteries, but is expensive compared to Chinese low end hub driven bikes, which wouldn't have the same quality or warranty, but typically much higher battery capacity.
Battery can be charged on the bike, or removed easily. Battery is secured to the frame with a lock/key. Battery contains a number of LED indicators and a button to also check the remaining power, and also overall capacity left/usage compared to new.
Electronic Display
Both bikes come with the entry level, Kalkhoff "compact display". The display shows the speed, assistance mode, battery capacity and trip/total mileage. It's really a shame that the display cannot be removed easily, when the bike is locked on the street for instance.
The compact display does not have other informations found on the "large display" (available on more expensive bikes), such as expected remaining range in miles, cost per trip, trip duration etc. The large display also offers the user the option to change many settings directly, such as the dynamic/normal assistance mode (in addition to other modes, makes the assistance more responsive and with more torque), the diameter of the wheels (which can influence the assisted top speed), the motor stop duration during gear shifts etc.
Those settings can still be changed on the Impulse 9 and 10, but would require a visit to the dealer, and the appropriate electronic hardware.
I think that, given the large price difference between the Impulse 9 and 10, the higher model should really have benefited from the upgraded display and settings.
Once I have received mine and done a few trips, I shall provide some further updates.
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