It wasn’t so long ago that the term light E-MTB caused a general shrug of the shoulders. In the past two or three years, however, this category has emerged as one of the absolute rising stars among ebikes. The group of competitors offering drives for such bikes has become correspondingly well-known and potent. We are talking about motors like the Orbea EP8 RS, the Specialized SL 1.1, the Fazua Ride 60 or the BH 2EXMAG. Now a manufacturer wants to break into this phalanx, which until now has embodied the opposite of a lightweight e-mountain bike with only minimal support.
1. TQ HPR50 – the motor
2. TQ HPR50 – the battery
3. TQ HPR50 – the range extender
4. TQ HPR50 – the display
5. TQ HPR50 – the remote
A few days ago, at the Eurobike, the company TQ Systems presented its drive called HPR50. Trek has designed its full-suspension Fuel EX-e trail bike around it, the top version of which weighs just over 18 kilograms. For a manufacturer like Trek to ultimately reach such dimensions, the drive system has to be very light and very compact. In the case of TQ, it is primarily the motor that meets this requirement profile.
1. TQ HPR50 – the motor
The heart of the HPR50 is its harmonic pin-ring transmission, or HPR for short. The HPR120 from TQ was already based on this. Many of you will probably know it better under the title Flyon. Haibike had been using this elemental force with 120 Newton metres of torque since 2018, until it disappeared from the range again for the 2022 season. Much of what TQ learned from the HPR120 has been incorporated into the further development. Even if its approach differs, the technical foundation is, of course, comparable.
HPR50 motor
The patented HPR is an elliptical rolling strain wave gear. This makes TQ’s solution fundamentally different from the approach taken by companies like Bosch, Shimano, Yamaha, Panasonic and others. In their mid-mounted motors, they combine an electric motor with cog wheels and planetary gears. Usually, this is more massive, heavier and louder than a strain wave gear.
Special form of power transmission
TQ installs the motor and gearbox in a narrow magnesium housing. The gearbox itself basically consists of three more complex parts. One of them is an oval disc. Inside it, more than 100 pins move in waves between an inner and outer cog wheel. While the inner rim rotates, the outer one remains rigid. This works because the inner cog wheel has fewer teeth than the outer one. This provides the necessary clearance for this movement.
Inner and outer cog wheels are always connected to each other via several pins in the harmonic pin-ring transmission.
The pins act as transmitters for the transmission. While the transmission is working, a rotational movement starts in which almost always all pins are involved. This results in a friction contact that is of a completely different quality than that of an ordinary gear wheel, where the contact is limited to a few teeth.
HPR50 drive in exploded view
The small number of parts used in the HPR transmission automatically reduces the number of things that can break. Issues such as wear due to friction or the generation of noise hardly play a role in TQ’s unit.
Regular bike as a role model
One of the biggest advantages of the motor is the small amount of space taken up by the gearbox. One result is the Q-factor of just 135 millimetres. When the pedals are this close together, it not only increases the efficiency of the power transmission, but also provides a riding experience that is very close to that on a regular bike. For comparison: The values of the competitors mentioned at the beginning range between 158 millimetres and 181 millimetres.
Due to its small size, the motor hardly stands out visually at the bottom bracket.
In general, TQ draws attention to a natural riding experience. In action, the drive was said to be significantly quieter than the competition. Since we have not yet been able to test a bike with this drive, we cannot compare this statement with our own experience. As an alternative, let’s look at a few figures. With a weight of 1,850 grams, TQ comes in at just under a hundred grams less than the Ride 60. The mechanical power is noticeably lower at 300 watts compared to Fazua’s 450 watts. Not surprisingly, the HPR50 also lags behind this competitor in terms of torque. However, the discrepancy is not as great with 50 Newton metres compared to 60 Newton metres.
Familiar trio
According to its own statement, TQ has deliberately limited itself to three support levels that you can select on the HPR50. With Eco, Mid and High, the manufacturer is roughly on the same level as the Ride 60 and its Breeze, River and Rocket levels, which feature an additional boost mode. In the app, you can set your own characteristics for the respective levels and configure them accordingly.
HPR50 motor unit at a glance
- Torque: 50 Nm
- Power: 250 W (nominal)
- Maximum power: 300 W (mechanical)
- Weight: 1.85 kg
2. TQ HPR50 – the battery pack
The intube battery that comes with the drive weighs 1,830 grams and has a capacity of 360 watt hours. TQ uses the 18650 cell size. Other manufacturers have recently been tending more towards the 21700 size.
You can read how much energy is in the cells from five small round LEDs. However, you can only see them when you remove the battery. How easy or complicated this is depends on how the bike manufacturer has integrated the battery. TQ has designed it in such a way that it can be permanently installed or planned as a removable version. In the case of the Trek Fuel EX-e, for example, two screws near the bottom bracket have to be loosened. Thanks to a charger with a charging current of four amps, a discharged battery is recharged to 80 percent within 90 minutes.
To keep the frame of the Fuel EX-e as stable and light as possible, Trek has opted for a relatively small opening through which the battery can be pulled out at the bottom.
Sporty design
In calculating the range, TQ assumes a weight of 75 kilograms for the riders. In the strongest support level, they can expect about 1,000 metres of altitude and two hours of riding time. Three hours of riding time and a maximum of 1,500 metres of altitude can be expected in the medium support level. Those who are content with the Eco mode can rely on the drive for four hours and gain a maximum of 2,000 metres in altitude.
HPR50 battery
HPR50 battery at a glance
- Capacity: 360 Wh
- Weight: 1.83 kg
- Charger: 4A Charger
3. TQ HPR50 – the range extender
Another 40 to 50 percent are added to these values if you use a range extender as well. It adds another 160 watt hours and is about the size of a 500 millilitre water bottle. Its additional 900 grams fit into any standard bottle cage. It can be conveniently connected to the charging socket integrated in the frame. Practically, this has a separate charging port. If you connect the charger to the ebike system via this port, the main battery is charged first and then the range extender. If you interrupt the charging process, the power will have flowed to where you need it most.
-
- HPR50 range extender
-
- Even in frame size S, there is still space for the additional battery.
HPR50 range extender at a glance
- Capacity: 160 Wh
- Weight: 0.9 kg
- Charger: 4A Charger
4. TQ HPR50 – the display
You can operate the new system from TQ via a display integrated into the top tube. When developing the display, the manufacturer placed great emphasis on making it easy to read in a wide range of lighting conditions. The two-inch O-LED display features a light sensor. If the sun shines directly on the screen, the display becomes brighter and vice versa. In terms of information, you can read off what you can expect. In which support mode am I riding? How much capacity does the battery still have? How far will I get with it? And so on.
HPR50 display
The exact functionality of the display depends on whether bicycle manufacturers use it as the sole control unit or combine it with the remote control on the handlebars. In the latter case, the single protruding button is used to scroll back and forth between different screens. Thanks to an integrated ANT+ interface, you can connect your ebike to your smartphone or bike computer. This will please those who like to ride with a larger screen on the handlebars and often use navigation.
A light sensor regulates the illumination of the display integrated in the top tube.
HPR50 display at a glance
- Screen size: 2 inch
- Type: OLED
- Connectivity: Bluetooth 4.0 / ANT+
- Charge level indicator / support mode
- On/Off switch
5. TQ HPR50 – the remote
The aforementioned remote control on the handlebars is somewhat reminiscent of the minimalist SW-EM800 rocker switch from Shimano and is even slimmer than the Mini Remote just introduced by Bosch. By default, you can switch between the support modes, activate the push assist and the light at the touch of a button. If you want to do more with it, you can define additional button combinations via the app.
-
- HPR50 control unit
-
- According to TQ, the remote offers good haptic feedback on the button press.
HPR50 control unit at a glance
- Connectivity: Bluetooth 4.0 / ANT+
- On/off switch
- Support mode
- Light
- Walk assist
Pictures: TQ-Systems GmbH
Hi Matthias, thanks for your reply. I really like this motor and would like to see it in an E-Caliber. I am going to wait a few months before buying a light weight e-bike and am holding thumbs that Trek uses it in their E-Caliber. Cheers
The system seems to have many advantages over the Fazua Ride 50 in the Trek E-Caiber. Do you think Trek will use the TQ system in the E-Caliber going forward?
Hello Gavin,
Well, we are not that close to Trek to know, whith what they’ll come up. However, this could be an option since they would have learned much using the TQ drive with the Fuel EX.
Cheers, Matthias