Kalkhoff Agattu i8 HS 17Ah

The Agattu Impulse 8 HS is a comfortable and very capable urban style electric bike. It delivers excellent range, comfort and utility with integrated fenders, a basic suspension fork, seat post shock, dynamo powered lights and a standard sized carry rack that comes with an integrated mini-pump. This is the most popular model that Kalkhoff sells in Europe it’s not difficult to see why. Given the four step-thru frame sizes, it’s easy to mount and handle for just about anyone. The smallest of these “wave” frames actually comes with smaller 26″ wheels that bring the frame closer to the ground. All other sizes (including two high-step “diamant” frames) come with more standard and efficient 700c wheels (that’s 28″). With shift sensing technology that cuts the motor momentarily as you adjust pedal speed, powerful hydraulic rim brakes and a two year warranty, this is the kind of electric bike that could be a reliable commuter or touring ebike.

The motor driving the Agattu 8 HS is a 250 watt mid-drive Impulse 2.0 offering 70 Newton meters of torque. While there’s no true throttle mode (just a slow walk mode) the bike is fun and responsive in one of three pedal assist settings. I didn’t struggle at all to climb with this bike even in higher gears (I tested it a bit off-road and climbing a large paved hill in the video review above). The motor control system measures rear wheel speed, pedal cadence and pedal torque to activate and power the bike. It’s responsive and smooth though not as instantaneous as the Bosch system. It is perhaps quieter however and the shift sensing technology felt a bit smoother. I especially like the chain guard surrounding the front sprocket and the smaller profile of the Impulse 8 motor which nearly disappears at the bottom bracket. Both rider and motor benefit from he Shimano Nexus eight speed internally geared hub at the rear. It’s clean and elegant, though perhaps heavier than a traditional cassette (this ebike weighs about 58 pounds total depending on the frame size). Because it doesn’t require a traditional derailleur the chain is kept short, tight and secure. The one complaint I do have about this drive system is that neither wheel on this bike offers quick release. The miniature pump could help to extend your range slightly if you got a slow leak but you’d need actual tools to swap tubes.

The battery powering the Kalkhoff Agattu Impulse 8 HS offers an impressive 36 volts of power and 17 amp hours of capacity. That’s enough for over 100 miles of range on the lowest level of assist thanks to the efficient center drive motor. This and other Kalkhoff “Impulse 2.0” battery packs are some of the best I’ve seen in terms of design because ithey out of your way, keep weight low and centered on the frame, are protected by the frame in case of tips, have a sturdy locking core for security, an integrated LED battery level indicator and they can be charged on or off the bike. They basically have everything you could want and use premium Lithium-ion cells that are known for being reliable and light weight. If you used the bike to commute to work you could easily bring the battery inside for safer storage even if you weren’t topping it off. The integrated handle is comfortable and sturdy, helping to reduce the potential for drops which could damage the plastic casing. To maximize the life of the pack, I recommend storing it a cool dry place while keeping the charge level between 20% and 80% at all times. Even though the battery casing itself is rectangular and not fully integrated into the tubing of the frame, I think it blends in more than some of the bottle-shaped batteries on other electric bikes I’ve tried. The dark gray/black paint is a nice touch that blends in with the sparkly black frame. Mounting the battery is very easy thanks to a pivot system that helps to line up pins (it mounts from the side) and the rear fender protects the electronics well from water and mud. There’s no extra controller box and all of the wires are run through the frame tubing. I love that this battery design allows for bottle cages on the seat tube and downtube of the “diamant” high-step frame but wish they would have included them on the “wave” low-step as well.

Activating and adjusting the drive systems on the Agattu Impulse Eight HS is very intuitive, probably one of the simplest I’ve seen while still delivering advanced drive modes. Once the battery is charged and mounted you just press the power button on the input pad which is mounted very close to the left grip. I love that both the LCD display and button pad are backlit… The LCD panel is not removable but it is small, sturdy and adjustable in terms of angle (to help reduce glare). As it powers up, the display says “Hello” and then quickly switches to show your speed, battery level (with 10 increments), drive mode (Eco, Sport, Power) and a trip/odometer. You can easily change between mph and kilometers by holding the select button and you can reset the trip meter by holding the minus button. I found myself riding in Power mode for the tests and noticed that this bike requires a bit more torque to activate the motor which means you get more of a workout than some other ebikes. I imagine that helps to extend range and possibly contributes to the quieter operation of the motor. There is also a walk mode which can be activated by holding the plus button for a few seconds, this can be useful if you’re heading up a hill pushing the bike instead of riding it. If you want to change from miles to kilometers just hold the set button for a few seconds and it should switch.


  • The high-step “diamont” version of the Agattu Impulse 8 HS offers two mounting points for adding bottle cages (one on the seat tube and one on the downtube)
  • The Selle Bassano Feel GT saddle is larger and more plush than other Kalkhoff electric bikes I’ve tested, it still feels good to pedal with and shouldn’t chaff thighs
  • Premium Ergon ergonomic grips, basic suspension fork and seat post shock make this bike easier to ride for long distances or touring
  • Excellent battery design… low and center on the frame, locking but key is not required to be left in when riding, convenient charge port with cover, sturdy handle for easier carrying, built in LED power level indicator
  • Internally geared eight speed Shimano Nexus hub stays cleaner and requires less maintenance than a traditionally derailleur and cassette, it does weigh a bit more but it also keeps the chain shorter which avoids clanking and chips on the chain stay or dropped chains
  • Great all-weather features including full length fenders (that protect you, the rack and the battery) as well as a chain guard to keep your right pant leg clean
  • Professionally run cables go through the frame which reduces snags, the bike comes in four sizes and includes an adjustable angle stem for really dialing in fit and going more upright or relaxed upright
  • Extremely responsive drive system measures rear wheel speed, pedal cadence and pedal torque for quick motor activation and cutoff
  • Proprietary shift detection system works with cassettes or geared hubs and functioned very well during my ride test, no mashing or banging
  • Good weight distribution with motor and battery mounted near-center on the frame, the battery stays out of the way for easy stand-over
  • Light weight charger only weighs 1.5 lbs and runs cool and quiet, will easily fit into a bag for extending trips – charging at the office etc.
  • Dynamo hub powered LED lights function whether the battery is charged or not and the lights are well mounted and sturdy, reflective tire sidewall stripes and standard plastic reflectors enhance the bike’s visual footprint
  • Hydraulic rim brakes offer excellent stopping power and are easy to activate smoothly without much effort
  • LCD display panel is backlit and swivels to reduce glare, it feels solid and is small enough to stay out of the way but the readouts are clear and well executed, rubberized button pad is also backlit and easy to reach without taking left hand off the grip
  • Rear rack uses standard gauge tubing which will work with the widest range of panniers including many clip-on systems, it connects to the fender for reduced rattling, includes a nice spring latch for small light weight items and includes an integrated mini-pump