- A premium compact electric bike with excellent weight distribution and a powerful responsive motor
- Up to 85 miles per charge, utilitarian fenders, chain guard, carry rack and dynamo powered LED lights and a standing light feature that stays lit for several minutes after the bike stops
- Unique space-saving features (folding pedals, swiveling handle bar), quick adjust handle bar and seat height, solid two year warranty
This review is for the 2015 Sahel Compact i8 from Kalkhoff. It’s fairly similar to the 2014 version but offers a more sophisticated LED display panel with multiple readouts and comes in white and black.
The Kalkhoff Sahel Compact Impulse 8 is a fun, high quality compact electric bike that fits short and tall alike… comfortably. The extra-long quick adjust seat post and stem are easy to setup but don’t wobble or feel flimsy. The reinforced x-style downtubes give the bike a stiff and sturdy feel but let you mount and stand over easily and the hydraulic rim brakes are very competent. This is a German engineered powerhouse that climbs and endures very capably. While the frame doesn’t fold in half or scissor up, the pedals do fold and the stem twists 90 degrees for true compact storage without the added weight and jitter of hinges. What you get here is a surprisingly comfortable, all-weather electric bike that’s fun and safe to ride. With a two year warranty and support from one of Europe’s largest conglomerates, Pon Holdings (owner of Derby Cycle, Gazelle and Cervelo) it’s an expensive but truly capable machine.
The motor driving the Sahel Compact i8 is a 250 watt mid-drive offering 70 Newton meters of torque. While there’s no true throttle mode (just a slow walk mode) to test up hills, I didn’t struggle at all to climb with this bike even in higher gears. 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 and the shift sensing 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. The Compact i8 offers eight pedaling speeds activated through a Shimano Nexus internally geared hub at the rear. It’s clean and elegant, though perhaps heavier than a traditional cassette (this ebike measured at 50 pounds total). Because it doesn’t require a traditional derailleur the chain is short, tight and secure. Ultimately, the motor benefits in the same way that you do as a rider when you switch from easy to hard gears and that extends the range and improves climbing ability. The one complaint I have is that the front wheel offers quick release but the rear does not which complicates flat tire fixes on the go.
The battery powering the Kalkhoff Compact Impulse 8 offers an impressive 37 volts of power and 11 amp hours of capacity. That’s enough for up to 85 miles on the lowest level of assist thanks to the efficient centerdrive motor. The pack is one of the best I’ve seen in terms of design because it stays out of your way, keeps weight low and center on the frame, is protected by the frame in case of tips, has a sturdy locking core, an integrated LED battery level indicator and can be charged on or off the bike. This means you can charge at work or bring the battery inside for ideal storage in a cool dry place (to extend the life of the pack, keep charge level between 20% and 80%). Even the charge port interface itself is an improvement over most other batteries. It uses the EnergyBus standard that connects magnetically (like an Apple laptop) which helps to reduce accidents if/when a cord gets tripped over. And even though the battery casing itself is square 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. Mounting it is very easy thanks to a pivot system that helps to line up pins (it mounts from the side) and the rear fender protects it well from water and mud.
Activating and adjusting the drive systems on the Compact Impulse 8 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 feeling and adjustable in terms of angle (to help reduce glare). So the display says “Hello” and then quickly boots up 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. I imagine that helps to extend range but it also means you get more of a workout.
For an electric bike with a 250 watt motor and 20 inch wheels that requires so little space this is really a comfortable and capable bicycle. Once the seat post and bars were adjusted I almost forgot I was riding a compact model altogether and the off-road and climbing never felt unstable or flexy. The low rise bar with its semi-swept back design offered a more upright seating position that would work well around town. If I owned an RV or yacht and wanted an electric bike that actually felt good and could go the distance compared to most of the cheaper folding options, this would be it. Even an ebike solution for my apartment with its limited space, I think I’d choose this because the drive system is so durable. While it’s not the lightest thing in the world, the removable eight pound battery definitely helps and that quick release front wheel does too. The unique frame works great for mounting and riding but might be difficult to fit into hanging car or bus racks… though given the generous range you might be able to skip public transit altogether.
- 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
- Battery pack features a sturdy locking core for security, has an LED indicator for testing charge level on or off the frame, is easy to mount, has an integrated handle for transporting and can be charged on or off the bike with a fancy magnetic EnergyBus port
- 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.
- Great all-weather accessories including a plastic chain guard to keep pants clean and full length matching fenders that also protect the battery pack
- 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
- Unique extra-long seat post and stem make this a comfortable ride for short or tall riders and are easy to adjust with quick release systems
- Clever twisting stem allows the handle bar to turn 90 degrees which combines with the folding pedals for a narrow storage profile
- Comfortable gel saddle is narrow enough to support active pedaling without chafing thighs but also softens bumpy terrain, feels really good and compliments the premium Ergon ergonomic grips
- Hydraulic rim brakes are unique but 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
- Clean look available in black or white, the integrated wires stay out of the way and so does the adjustable kickstand
- Internally geared hub stays clean and may require less maintenance than a traditional derailleur, it also allows for a shorter tighter chain which won’t fall off as easily
- 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 and includes a nice spring latch for simple items
- Only available in one standard unisex frame size… however, the seat and bar height is very adjustable to accommodate a wide range of rider body types
- Limited suspension, ride can feel more bumpy due to smaller diameter 20″ wheelset but the comfort gel saddle and larger tires help
- Magura HS11 Brake levers do not offer motor cutoff, I’ve noticed that while stopped it is possible to accidentally activate the motor by pushing the pedals for stability