TQ – HPR50 Test

Everything that makes the TQ motor special

TQ is a German company that makes many types of motors and, for many years, had available on the market for e-bikes the TQ HPR 120S motor, which has the largest torque of 120 N/m on a street-legal pedal 3-bicycle. This can be found on two brands of bikes—Spitzing and Haibike. So, TQ has now drawn a solid line in the sand with this new lightweight motor, the TQ-HPR50. It is a significant development for TQ and for the e-bike market.  The size and power-to-weight ratio of the TQ-HPR50 are arguably the best on the market today. The secret to this system is the Harmonic Pin-Ring transmission. 


On specifications alone, this motor might not be too dissimilar compared to other lightweight motors; however, the actual package is very different. As observed on the Trek Fuel EXe, the first production bike to use this motor, there is very little change to the bike compared to a standard mountain bike when it comes to functional design and interfaces. 

The real difference, though, is that the motor is barely a few inches across in circumference. This provides frame designers with significantly fewer limits on the geometry and frame forms they come up with. There are other lightweight motors that come close in size, but the TQ stands out, as the frame’s profile resembles a standard mountain bike when seen next to its electric version. 

TQ’s chosen display is also small—just 2 inches in size—and is integrated on the top tube, with the remote being as small as any competition. The system uses a discrete 360Wh battery that is stored in the downtube, and it also allows range extenders to be used, which fit in a water bottle cage on the frame, which, again, are no bigger than a 500ml standard bike water bottle. 


The HPR50 motor is extremely quiet. It’s as silent as a hub motor yet with more torque. When pedaling, we found the motor feels very different as well. The first part of the first pedal stroke is soft and very natural, with the motor ramping up power immediately after the first pedal pressure but increasing in an imperceptible way. There is nothing on the market that has this type of sensation. This whole process is almost silent in operation. Once up to speed at a cadence around 85 rpm, it is possible to hear a very low whine noise, but you have to be on a smooth road and listening very carefully to hear it. This level of noise reduction is due to the Harmonic Pin-Ring design that is based around a large sprocket moving inside a similar, slightly larger sprocket that’s directly driving the chain wheel. Silence can be put down to the lack of gears in the drivetrain.  

The actual power sensations that the rider feels according to the different support modes are one step below that of a full-power motor. We found the top mode to be equivalent to a detuned Trail mode on a Shimano EP8 motor. Eco mode was much lower than a normal Eco mode setting and almost like a non-assist bike. 

This is not a motor that should be used as a shuttle motor, boosting the rider to the top of a bike park so that they can knock out park runs all day. It’s evident that this motor is for an athlete who wants to pedal to their destination but with the edge of leg fatigue reduced on those parts of the ride, which would sap the leg energy of a normal bike rider. The full power mode is useful on steep climbs to take the edge off, and while it keeps you moving, you need to keep pedaling or the battery range will decrease quickly. This is not the type of motor to just rely on to sit back and be pushed up the hill without doing any leg work. 

The display is easy to read and not distracting, giving vital information when needed, including battery level and support mode and other typical settings or data including cadence. There is a button on the display to change view mode. The remote is easy to find, small and soft to the touch. It was not our favorite remote on the market, but it is an interesting design. Once back from a ride, the battery can be charged on board via the very easy-to-access charge port on the downtube. Full charge took about two to three hours.


Buy a TQ-HPR50 motor-equipped bike if trail bike performance is fundamental to your enjoyment or you are an athlete that wants a complementary training assistant that helps you stay more readily in your heart-rate training zone. It is not for a rider looking for a shuttle solution for park laps. Like to explore and want to discover the wild? Then this might be the motor solution for you, especially if you equally like to pedal and want to “earn” your descents. 


After some limited but spirited initial rides aboard our Trek Fuel Exe test bike, we had a good idea of how this motor will fit into the market. As the first brand to spec it, Trek has made an excellent choice, as their product now sits as a benchmark to be compared against. What was more immediate in our experience was that the size between the TQ-HPR120 and the TQ-HPR50 might be the magic motor that storms the market in the future and gives the other motor makers a run for their money. Competition for the future of electric transmissions is going to be fierce, and this latest idea is going to gain a lot of traction when people wake up to the quiet and smooth operation.



50 N/m


1,850g (4.08 lb.)

360 Wh 1,830g (4.03 lb.) and range extender 

Display: 2” with ANT+