EMTB test TQ mini motor: Trek Fuel EXe 9.9 XX1 AXS with TQ HPR50 motor
Florentin Vesenbeckh
· 13.11.2022
The lady who passes me on her e-MTB looks round at me with a friendly smile. "Young man, at your age I was still riding without an E," she says apologetically. Before I can even reply, she's zooming up the hill in turbo mode. My gaze travels down the seat stay of my Trek bike in shame and lingers on the blue TQ logo. Quietly, I can hear the TQ HPR50 motor purring along with the sound of the tyres rolling on the asphalt. The new light engine from Bavaria, which Trek was the first brand to install in its Fuel EXe and which the Americans were involved in developing. Have the two partners come closer to the big goal of the e-bike industry, this magical triad of the light e-MTB category?
All information about the Light-E-MTB test: Trek Fuel EXe 9.9 XX1 AXS with TQ HPR50 motor
Practical test: The Fuel EXe on the trail
Fully networked: Trek Central app
Models and prices
Test results and technical data Trek Fuel EXe 9.9 XX1 AXS
Performance barometer: Average speeds in comparison
Interview with TQ developer Toni Roßberger
TQ HPR50: Quiet and compact
Firstly, it should look like a non-motorised mountain bike, secondly, it should sound like a non-motorised mountain bike and thirdly, it should feel like a non-motorised mountain bike.
non-motorised mountain bike. Trek and TQ seem to have fulfilled points one and two with flying colours. The motor is record-breakingly compact, not visible at all from the chainring side and barely visible from the left.
The background noise is also barely noticeable. In many riding situations, for example on gravel, the drive whirring of the mini motor is completely drowned out by the ambient noise. Only when accelerating before steps or technical passages, when the cadence is briefly above 100, does the drive whistle a little louder.
Unfortunately, the Trek Fuel EXe plays the whisper card on the descents. The motor doesn't make a sound here, because due to its design, the gear rattling that characterises Bosch and Shimano motors is completely absent. Nevertheless, there is no peace and quiet. The cables and wires rattle clearly in the frame, and the multi-tool in the head tube also makes a noise. Unnecessary discord.
You are looking for the Trek Top Fuel? We tested the latest version of the trail bike here: >> Trek Top Fuel Trek Top Fuel 9.8 GX AXS Gen 4 - The 4th generation in the 2024 high-end trail bike test
>> Here you will find the Long-Travel-Bike Trek Fuel EX 9.7 on test - all-mountain bikes for around 5000 euros
Back to the triad. How does the Fuel EXe feel? The motor's thrust is very subtle and natural. With the moderate power, this is easier to implement than with a big electric motor, of course. TQ specifies 50 Newton metres and 300 watts as the maximum values. But it's not just the tame power that makes for the smooth handling. The software tuning is superb, and the motor is also helped by the patented HPR gearbox technology. Engaging the engine takes place
almost no idle travel and absolutely inaudible. Where many other drives start their thrust with a distinct clack, the TQ HPR50 starts directly and silently. This feels valuable and natural. The motor thrust is never intrusive and is decoupled.
And how powerful is the mini motor? At a high cadence, the thrust is decent. The performance here is roughly midway between the rather weak Specialized SL 1.1 and the significantly more powerful EP8 RS from Orbea. The difference to power motors is most noticeable at low cadence. On technical climbs and steep gradients, you have little torque reserves and the motor hardly lifts the rider over edges or key sections at low cadence. Starting off on steep terrain also requires a lot of power from the legs. In this discipline, the difference to the EP8 RS is clearly noticeable, which clearly feels more powerful. Overall, the newcomer is more orientated towards the mid to lower power range of the new light drives. On the other hand, in addition to the natural ride feel, the way the bike fades in and out of the pedals when oscillating at the 25 km/h limit is outstanding. You can hardly tell whether the motor is pushing or not. Neither acoustically nor haptically. The next big point on the naturalness scale. All in all, the pedalling and riding experience with the HPR50 actually comes very close to classic biking. And how does the Fuel EXe ride downhill?
Practical test: The Fuel EXe on the trail
On the trail bike, you sit in a strikingly sporty position. The front is low, and the extra-wide handlebars (820 mm!) also stretch the rider over the bike. With a slightly higher cockpit and narrower handlebars, we felt more comfortable overall. The seat angle is super steep on paper, but flattens out significantly in practice as the saddle extension increases. Long-legged riders sit a little further back. However, the Fuel EXe really comes into its own when the rider gets out of the saddle and the trail points downwards. Here you are centred and well integrated into the bike. The long reach gives you plenty of room to manoeuvre and, together with the slack head angle, the bike conveys a lot of riding confidence. This is also helped by the plush and plush suspension, which virtually sucks itself to the ground on root carpets. The rear suspension feels like it has more than 140 millimetres of travel, but still conveys a poppy and lively riding sensation.
All in all, the Fuel EXe definitely shows the characteristics of an enduro bike. In rough terrain, it is significantly more potent than its direct competitors, the Orbea Rise or Specialized Levo SL. These, in turn, have an even more agile ride feel than the Trek. But the newcomer can also clearly set itself apart from classic E-MTBs in terms of handling. The Fuel EXe rides a whole lot more nimbly than the lively and light Rotwild R.X 735, for example. All in all, Trek's light bike is a great compromise between full-bodied off-road expertise and agile lightness. However, we would rather recommend the bike to riders who focus on sporty trail to enduro use. For them, the option of pimping the bike with a 160 mm fork can also be exciting. The manufacturer has officially approved this option. Moderate touring bikers might want more neutral handling and uncomplicated climbing characteristics. Because on technical climbs, the bike has to be steered very consciously in order to stay on course.
Fully networked: Trek Central app
Of course, Trek and TQ have also thought about smart networking. The HPR50 can communicate with your smartphone via the new Trek Central app. This allows the three U-levels to be fine-tuned to individual preferences in terms of support, maximum power and response behaviour. The logic is simple and the parameters are sensibly selected. The motor data can also be easily mirrored to third-party devices, such as a Garmin computer.
Models and prices
Finally, let's take a look at the eponymous component of the Light category: the weight. At 18.8 kilos in size L (EMTB measurement, without pedals) and lavishly equipped with carbon parts, the Fuel EXe is ultimately far from a new record weight. Considering the super-light drive system, this is a little surprising. At least Trek has a removable battery on its credit side. A weight-critical luxury that the lighter competitors such as the Orbea Rise and Specialized's Levo SL don't allow themselves. Speaking of Specialized. When it comes to pricing, the two industry giants haven't had much in common in recent years. With the top model of the Fuel EXe for a whopping € 14999, Trek even tops the S-Works Levo SL by € 499. However, Trek starts at € 6499 with the Fuel EXe 9.5, which already has a high-quality carbon chassis. According to Trek, the bike should stay under 20 kilos in size M. However, the spec with the Rockshox 35 fork is very modest for this price.
Test results and technical data Trek Fuel EXe 9.9 XX1 AXS
PLUS: Racy trail geometry; strong chassis; quiet drive noise; natural ride feel
MINUS: Trains rattle in the frame; motor derating in continuous full-load operation; very expensive
Conclusion from Florentin Vesenbeckh, Test Manager EMTB:
"Super natural ride feel, discreet looks and a quiet drive unit: the Fuel EXe comes pretty close to the ideal of an unobtrusive light eMTB. It's a shame that Trek diminishes the sound advantage with rattling add-on parts. Downhill, the Fuel EXe is a racy sports bike with enduro qualities. It does not set a weight record. The subtle power of the HPR50 predestines the bike for sporty, fit bikers who want natural support. Anyone looking for a shuttle for steep climbs could be disappointed by the power and stability of the motor."
General information
- Price: 14999 Euro
- Sizes / frame material: S / M / L (tested size) / XL / Carbon
- More info/Trek website
Measured values²
- Weight²: 18.8 kg
- Reach altitude¹: 1046 (+213)hm
- Average speed: 8.9 km/h
- Centre of gravity height: 528 mm
- Handlebar width: 820 mm
- Crank length / Q-factor: 165 mm / 198 mm
- Ground clearance⁴: 502 mm
Equipment
- Permissible total weight³: 136 kg
- Fork / shock: Rockshox Lyrik Ultimate / Superdeluxe Ultimate
- Suspension travel (f. / h.): 150 mm / 140 mm
- Telescopic seatpost: RS Reverb AXS, 170 mm
- Brake / Disc Ø (front / rear): Sram Code RSC / 200 mm / 200 mm
- Wheels: Bontrager Line Carbon 30
- Tyres (f. / h.): Bontrager SE5 Team Issue TR, 29 x 2.5"
¹ The reach height was determined during standardised test rides on an asphalt climb with a gradient of 12.2 percent. Highest support level, 150 watts pedalling power of the rider, rider weight including equipment 89 kg. The altitude metres in clearly reduced emergency mode are shown in brackets. The average speed refers to the journey with full assistance.
² Determined on the test stands in the EMTB test laboratory, weight without pedals. Battery weight incl. screwed-on cover where applicable.
³ Manufacturer's specification
⁴ Step test, measured with the rear wheel raised by 36 centimetres.
Performance barometer of the TQ HPR50
How powerful is the new TQ HPR50? We got up close and personal with the newcomer using modern measurement technology and compared it with its direct competitors.
In order to classify the performance values of the HPR50 more precisely, we equipped the Fuel EXe and three comparison bikes with standard tyres and measurement technology from Garmin. We ran through various test scenarios. The SL1.1 motor from Specialized (1.9 kg) and the EP8 RS (2.65 kg) from Orbea served as sparring partners. In order to categorise the values determined in the e-bike context, we also ran a Bosch Performance CX as a power reference.
Scenario one: maximum performance. The candidates complete a short sprint on a climb with an elevation gain of around 30 metres. The HPR50 is positioned pretty much in the middle between the light but loud SL 1.1 and the significantly heavier EP8 RS. In a second series of measurements, we selected a lower cadence in order to get to the bottom of the torque. This confirmed our impression from practice: The EP8 RS can set itself apart more clearly from the HPR50.
Scenario two reflects a continuous load on steep, long climbs. This is not the core competence of a light drive, but this discipline is also part of a balanced performance assessment. All motors had to compete in the demanding turbo mode. After around 15 minutes, the HPR50 began to derate noticeably, i.e. the power was reduced. At the end of the steep 400 metre ascent (12.2% on average), the display in the Fuel EXe only showed a maximum of 155 to 170 watts. At the beginning it was 300 watts. The outside temperature at the time of the test was 25 degrees. The other drives were able to keep their maximum output largely constant over the entire distance. The main reason for the relatively early cut-off of the TQ is the small surface area available to it for dissipating the heat. If you are travelling in medium mode and only switch on the turbo stage briefly, you will not notice this shortcoming. A heavy rider, long, steep climbs and heat exacerbate the problem.
Average speeds in comparison*
Interview with TQ developer Toni Roßberger
EMTB: What is the technical difference between the HPR50 and the competition?
Toni Roßberger: What fundamentally sets us apart from other drive concepts is our very high power and torque density. We can deliver a lot of power in a small installation space. This is primarily due to our special harmonic pin ring gearbox. In other mid-mounted motors, the gearbox accounts for a large proportion of the volume, weight and components. We need far fewer parts, and these can also be smaller in size because almost all the teeth of the pin ring engage simultaneously during power transmission, as opposed to just one or two teeth in conventional gearboxes. In addition, our unique force sensor is much smaller than conventional torque sensors and can still process and analyse more input from the driver.
What did you want to achieve with the compact motor?
A drive that you hardly notice when driving because it pushes so harmoniously. Our HPR gearbox also helps us here because, unlike others, it is practically backlash-free. This enables direct power transmission. We also have our own approaches to sensor technology and freewheels, which make the driving experience smoother.
Why is the motor so pleasantly quiet?
We have invested part of our potential, i.e. our power density, in noise development. We work with a relatively low gear reduction ratio, two to three times lower than other drives in this class. This means that the engine speed of the HPR50 is significantly lower than that of other mid-engines. The noise decreases quadratically with lower speed. Our specially designed electric motor rotates much more slowly and is therefore significantly quieter.
We had problems with derating under continuous load.
We have prioritised a natural riding experience with the HPR50, not maximum power. Nevertheless, the maximum peak power of 300 watts can be called up without restriction in the vast majority of cases. Under extreme circumstances, derating may occur. The software reduces the power because otherwise the housing would become too hot. This is because the standard stipulates a maximum value for touchable surfaces. Derating has no effect on the service life of the motor. In the usual area of application of the Fuel EXe, where uphills and downhills alternate, there is usually no noticeable derating.
Florentin Vesenbeckh
Editor CvD
