CURRIE EFLOW E3 NITRO
When you look at a 100-percent human-powered bicycle, you can pretty much tell what you are looking at. Whether it be a road or mountain bike, it’s safe to say that the bicycle has settled into a relatively predictable design box. In the world of e-bikes, manufacturers are still capable of thinking outside the box, and at times completely out of sight of the box. The eFlow Nitro hasn’t left the reservation or anything, but it does incorporate exterior-box-like thinking. It isn’t obviously a pedestrian commuter, yet it doesn’t shout “sport” like a true drop-bar road machine either, with the straight bar and somewhat generous tire size.
SIT ON IT
Two areas brand the bike as a non-conformist: the modest amount of front suspension built into the RST SS-A6-T fork with 30mm of preload-adjustable travel built into the steerer tube, and the aero-looking seatpost that doubles as the 36-volt, 10.7 amp-hour (a larger, 15 amp-hour battery is also available lithium-ion battery pack). You may charge the battery on the bike with a charging socket in the frame, or you can remove the battery. To remove the battery, raise the seatpost to full extension, then slide the battery off the bayonet mount. An adapter supplied with the charger allows the battery to be charged directly. You actually adjust the seat height by sliding the battery up or down in the frame. The “post” has marks to allow easy adjustment and a line that warns you have surpassed maximum extension. The seat mounts to the top of the post/battery.
A simple and reliable, direct-drive, 500-watt rear hub motor provides the assistance. The hub uses no gear reduction, but is wound for high torque. As a result, we found that the Nitro is aptly named. The performance is very impressive, with a great deal of assist available up to the legal 20 mph. The eFlow’s control unit allows the rider to choose either torque-sensing pedal-assist mode, or power-on-demand mode from a removable LCD. The LCD unit detaches with a simple twist to function as a key—no computer, no assist. It includes standard-bike computer functions like speed and distance traveled, and displays battery state of charge, power levels and regenerative braking conditions. With regen erative braking and torque-sensing, it is obvious that the Nitro has a sophisticated control package. Additional evidence of this is the sensor that examines frame flex (for rider weight), so you get best results when you sit on the Nitro before you power it on.
Small buttons on the side of the computer are labeled plus and minus, and they cycle the power modes up and down. Level one is plenty of support on flat ground. In all the modes, the Nitro climbs with strong assist, but using the POD mode and using the throttle while pedaling and utilizing the SRAM 2×10 drivetrain provides the bike with the absolute best climbing performance. With any hub motor, it’s important to keep the speed up on climbs. As you drop below 13 mph or so, you lose assist with each mph you drop. The single-speed motor has an rpm range where it makes the most torque. Motor rpm with a hub motor translates directly to mph. Fall below that sweet spot and you lose assist. The motor still helps, but it helps less at lower speeds. That isn’t a criticism of the eFlow, just a trait of the hub motor. You want the best help on hills? Keep your speed up. The plus side is that the Nitro makes keeping your speed up on climbs a breeze.
The battery on our test bike was able to last for about 23 miles of hard riding with lots of climbing. We probably could have beat that mileage figure by running the assist at the lowest level, but power is addicting, and we found it hard to resist the feeling of the Nitro charging up the climbs. Hills and headwinds won’t be a factor with the Nitro. In theory, the POD mode is for when you want to rest and let the bike do all the work, but we generally pedaled and just used the throttle to dial in the assist we wanted for the terrain.
With the Nitro’s assist, the SRAM 2×10 drivetrain worked great. For our riding conditions, we didn’t use the small front ring much, and perhaps we could have used more gear for the fast flat sections. Currie gifted the Nitro with an aluminum frame that is beefy where it needs to be. It isn’t overly unyielding on rough pavement, but we credit the largish Maxxis tires and the suspension fork for much of the smooth ride.
LIFE IN THE BIKE LANE
Currie says they will have a 15 amp-hour battery for the Nitro, and that would be fine with us. That would allow at least a 30-mile range riding at a sporty pace. The Nitro is fun and comfortable enough that we weren’t always ready to head home at just over 20 miles when the battery would be running dry. It would be even more fun to slam out 30 miles or more with this level of assist on tap.
Two models of the Nitro are available—our flat black test model (with a high top tube) is available in small, medium and large sizes. You can also get it in white with a dropped top tube in small and medium sizes.
One of the unique aspects of e-bikes is the way they change the traditional sport of cycling. With an e-bike, it becomes more about the ride since the misery is gone. Sure, you can still get plenty of exercise, but you are allowed the time and energy to enjoy the ride and the scenery more. The Nitro does nothing to detract from the ride. It has the riding position to exploit the joy of the powerful assist.
Motor: TDCM 500W Hi-Torque DC Direct Drive Motor
Battery: EV-rated rechargeable lithium-ion cells in power pack with advanced power management system 36V10.7Ah 396Wh standard
Battery life: 600 to 700 cycles
Charge time: 4–6 hours
Controller: Currie Electro-Drive, 36-volt with power state of charge function, pedal torque sensor and POD (Power On Demand throttle) selector
Top speed: 20 mph (rider weight, rider input and terrain contingent)
Range: 25–35 miles with normal pedaling
Drive: SRAM Apex front and rear derailleurs and SL700 shifters, 20-speed drivetrain
Brakes: Tektro Auriga E-Sub hydraulic disc with 180/160mm rotors front/rear, Tektro Auriga E-Comp brake levers
Wheels: Alex FR-30 26″ double-wall alloy rims with stainless steel spokes, QR axles
Controls: LCD display with power switch, battery state of charge, power mode/level selector, bicycle computer functions (distance, time, speed), monitoring of regenerative braking
Fork: RST SS-A6-T 26″ with preload adjustment, 30mm travel
Frame: Hydroformed aluminum, fender, rack and bottle mounts
Weight: 52 pounds (medium)
Sizes: S (18″, 46cm), M (20″, 51cm), L (21.5″, 54.5cm), LS-S (18” 46cm), LS-M (20″, 51cm)