Tern Link D8 with BionX Motor Kit: An Extra Boost When You Need It

by Tracy on January 11, 2014

Tern Link D8 with custom BionX motor

I always look forward to going to NYCeWheels to try out and review their products. I was excited to try something a little bit new and different. Peter suggested I try one of the lighter electric bikes in the shop, the Tern Link D8 with the BionX Motor Kit. This particular bike is equipped with the PL350 rear rack BionX model with a 350 watt motor and a 36V/6.4 Ah Lithium-ion battery. This was my first time ever riding an electric bike.

I initially noticed that the bike has a sleek look with its paintjob of a grey frame accented with baby blue that complemented the attached black rack, fenders and mud flaps. The black BionX kit easily blends in with the color scheme of the bike to give the complete Tern Link D8 with custom BionX motorset a seamlessly uniform appearance. The BionX Motor Kit does not add any additional bulk to the folding bike as it is installed underneath the rear rack. This helps keep the N-fold of the Tern Link D8 in the same dimensions as the model without the BionX Motor Kit and easy to take on public transportation.

This bike weighs approximately forty pounds in total with the BionX electric kit. The additional weight of the BionX Motor Kit on the Tern Link D8 folding bike made it a little more difficult for me to carry through public transit since it is about twice the weight than the regular folding bikes at the shop that I tried before. Despite the extra weight and my lack of upper body strength, I was still able to carry the bike down to the train platform; it just took me a bit longer.

The first ride home was quite an experience. I decided to take 85th Street westbound from NYCeWheels through the Central Park Loop to the Hudson River Greenway to get to Penn Station. Once I got to the loop I decided to use the BionX non-conservatively by aggressively using the throttle and pedal assist. From the first push of the pedal I felt the work of the BionX automatically giving an extra boost of power to my pedaling. It was surprising how smooth and effortless the pedal assist kicked in.

Tern Link D8 BionX consoleThe power of the BionX is controlled by the G2 console on the left side of handlebar. The console has an easy to read display with a backlight function that also turns on a rear safety light for riding during the night or poor weather conditions which can be switched on by holding the power button (upper left button) for four seconds. On the console, you can see the four levels of assistance (bars on right) and generation (bars on left) modes. When riding the bike there is Tern Link D8 with custom BionX motora control panel on the right handle to adjust the assistance levels and an extra red throttle button to give an extra boost of power. With the throttle button the top speed I maintained was around 11 mph during my route in Manhattan and my ride from the railroad station. The assistance mode helps aid you when pedaling. The higher you adjust the assistance levels, the less work your legs will have to produce when riding the bike. On the opposite spectrum, the generation mode that provides a level of resistance while the motor acts like a generator by recharging the battery of the BionX system. It gives a similar feel as if you were riding an exercise bike on the go. On the console you can also see displayed the speedometer and odometer to tell how fast you are traveling as well as how far you traveled.

The purpose of the BionX Motor Kit is to help provide assistance when riding the bike. For some riders an electric bike may be helpful for those who have difficulty pedaling due to a previous injury to their legs, biking long distances or generally when going on challenging steep hills. Most people do not know that eight years ago I had an athletic injury in high school when I landed awkwardly during volleyball practice from spiking. As a result I had torn my ACL and MCL ligaments in my left knee that required surgery in order to return to athletic activity and prevent further damage. After six months of recovery and rehabilitation I was able to resume in athletic activity, but only by using a sports brace for high impact activity to prevent future injury to the knee. When I push my limits, sometimes I do feel pain in my left knee. This is part of the reason I love to go biking since it is a low impact activity.

After about a total of twenty miles and a little over an hour of riding with aggressive use of the pedal assist and throttle, the battery life was only depleted about just under half its life. Recharging the battery was quite simple. The BionX Motor Kit comes with a power supply charger that connects to the BionX battery touch port by a four pin circular connector. Once the charger is plugged into a wall outlet, the bike takes about four to five hours for a full charge. The touch port has an LED ring that easily indicates when the battery is fully charged when it changes from an amber color to green.

Tern Link D8 with custom BionX motorTern Link D8 with custom BionX motor

Since I have started writing bike reviews for NYCeWheels, it seems that I have a knack for picking days to test ride these bikes during some challenging weather. Mainly this is due to the constant shift changes that I have in my other job and by chance of availability. In early December I took the Tern Link D8 with the BionX Motor Kit on one of my favorite paths on the west side of Manhattan, the Hudson River Greenway.

The Hudson River Greenway is the first path I took my Brompton for a spin in the city since it is an easy walking distance from Penn Station when I take the Long Island Railroad. My usual route is a loop from the Inwood stairs at the northern part of the greenway to Vessey Street in Lower Manhattan where the lower part of bike path has been closed off due to ongoing construction. There is another section closed off for construction by 133rd street that has a detour on to 12th Avenue to the continuation of the greenway at 135th street. This route is about a little over two hours and twenty four miles round trip. The majority of the greenway is relatively flat from Vessey Street to the Little Red Lighthouse with very few easy hills.

Heading north past the Little Red Lighthouse is where the greenway gets challenging. There are two steep hills to challenge your leg power. The first hill is just after you pass the lighthouse. I would rate this hill at moderate difficulty. After riding up the hill many times I had built up my leg strength, but I have seen many other bikers struggle on this hill. The most difficult hill is the switchback ramp just after the underpass tunnel. The high difficulty of this hill is due to its angle of incline at almost forty-five degrees with a short curve to the left about three-quarters of the way up to the top. I still find this particular hill hard to reach the top without getting off my Brompton at the curve and walking it to the top of the switchback. Therefore, I thought that this would be the perfect path to test the assistance of the BionX Motor Kit. On this ride I decided to use the BionX system more conservatively.

Tern Link D8 with custom BionX motorThe BionX worked like a charm up the hills toward Inwood. Using the power assist while riding the Tern Link D8 felt effortless as the BionX system allowed the bike to climb the steep hill without difficulty. I was able to pedal up the hill with just two bar levels of bike assistance without working my legs too strenuously. The third and fourth levels of assistance easily took the bike up the switchback at a faster speed. Once reaching the top of the switchback, the assistance mode can be turned off by squeezing the break lever that acts like a kill switch.

In the late afternoon I encountered a snow storm heading back south on the Hudson Greenway. The Tern Link D8 performed well on through the slick conditions as the tread on the Schwalbe Citizen tires was able to cut through the snow accumulation and not lose control. The fenders and mud flaps prevented the water from the path from getting on to my clothes during the snow storm. Since the conditions of the greenway were beginning to get a bit too dangerous, I switched the BionX system to the generation mode as I cautiously made my way back. After I made it back to my house, the BionX battery had at least three-quarters of battery life left after biking about twenty eight miles.

The Tern Link D8 with BionX Motor Kit was quite a joy to ride. I enjoyed the use of assistance mode for the steep hills that could bring difficulty in normal pedaling power. The throttle button gives you just enough burst of speed to help you not break a sweat on your ride. It is quite genius of BionX’s generation mode to have the bike recharge while in use. This gives less chance of the system draining out its power within a single usage. Overall, I would recommend the Tern Link D8 BionX Bike for any bike enthusiasts willing to give electric bikes a try.

Tern Link D8 with custom BionX motor


Read more blogs by Tracy Dong

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