Bulls Vuca Evo AM 2 endurance test: Pinion MGU and belt reach their limits here

The test of the Bulls Vuca Evo AM 2 E-Allmountain was not only something that endurance tester Andreas Kern was particularly excited about. The many moving parts of an e-MTB offer plenty of potential sources of error. The Pinion E1.12 MGU motor-gear unit attempts to eliminate some of these. The Gates CDX drive belt aims to eliminate another. Test rider Andi has also broken various chains in his life. As a BIKE touring author, he is constantly travelling in alpine terrain and has to be able to rely on his e-mountainbike. In the long-term test, he chased over 66,000 merciless metres of altitude on his Bulls Vuca Evo AM 2 - and broke a belt in the process.

The endurance test team: Andi vs. the Bulls

At first glance, the Bulls Vuca Evo AM 2 with its low-wear combination of Pinion gearbox and Gates belt is a perfect match for our long-term test rider Andreas Kern. Extensive tours through the Alps are a daily business for the Partenkirchen native and BIKE tour author.

Details of the Bulls Vuca Evo AM 2

• Price: from 7999 euros >> available here
• Drive: 12 gears, 85 Nm torque, SmartShift (automatic; can be disengaged)
• Battery: 720 Wh, removable; additional price with 960 Wh battery: 200 euros
• Material: Carbon frame with aluminium rear triangle
• Sizes: S, M, L and XL
• Wheel size: 29 inch
• Suspension travel: 150 / 150 mm
• Weight: 25.29/26.39 kg (EMTB measurement, size L, 720/960 battery)
• Permissible total weight: 150 kg

>> You can find our detailed report on the Pinion MGU motor with automatic shifting here.

Equipment

• Fork / Shock: Fox 38 Factory Fit4 / Float X Factory
• Gear system: Pinion MGU E1.12
• Brakes: Shimano XT, 220/203 mm
• Wheels: Formula hubs, Ryde Disc 30 rims
• Tyres: Maxxis Minion DHF / DHR II Exo, 29 x 2.6''
• Special features: Monkey-Link mount for front light, integrated rear light, Bulls carbon handlebars, 800 mm

Geometry

• Seat tube length: 470 mm
• Wheelbase: 1240 mm
• Reach: 465 mm
• Stack: 644 mm
• Steering angle: 66 degrees
• Seat angle: 74 degrees
• Chainstay length: 455 mm

>> You can read our first test impression of the Bulls Vuca Evo AM 2 here.

Details of Andreas Kern endurance tester

• Age: 53 years
• Height: 188 cm
• Weight: 90 kg
• Place of residence: Partenkirchen
• Favourite areas: Home trails in the Estergebirge, Wetterstein and Karwendel / "Away": Livigno, Dolomites and Briançon.

Permanent tester Andreas Kern works as a freelance touring author for BIKE. You can read some of his latest stories here:

• >> Karwendel: On lonely paths to the new Falkenhütte
• >> Kilimanjaro: The highest peak for mountain bikers in a self-experiment
• >> Livigno: The Chaschauna Pass in "Little Tibet"
• >> Upper Engadine: MTB tour of the Piz Bernina

The endurance test: 100,000 metres of altitude in use

Carbon belt drive, motor-gearbox unit and all-mountain suspension: the Bulls Vuca EVO AM 2 from Bulls was so innovative when it was launched in 2023 that it was subsequently exhibited in the German Museum. Nevertheless, it's a strange feeling when strangers spontaneously approach you. Not because you're so nice, but because your bike with its carbon main frame and aluminium rear triangle looks so exciting. "No more chain - and that works?" was by far the most popular question from bike-savvy passers-by last year, followed by: "There's a motor AND gearbox down there?" and "Surely this bike is priceless?"

>> Our in-house visit shows exactly how the Pinion MGU is manufactured

Let's start with the last question and work our way back bit by bit. 8500 euros RRP is quite an announcement. On the other hand, this is where the fun begins for other manufacturers. To spoil the conclusion right at the beginning: this investment is worth it! You get a state-of-the-art e-MTB with all-mountain suspension that is easy to swallow (150 millimetres of suspension travel front and rear), an innovative motor and gearbox unit (twelve buttery-smooth gears and plenty of uphill power) and extra juice (replaceable battery with up to 1,055 watt hours). Sounds like an egg-laying wool-milk sow in a bike costume. For me personally, an e-mountainbike basically only has to do one thing: work. Always and everywhere. It should also reach its limits downhill later than I do.

>> From the first tours and fast 3000 metres: This is how the endurance test of the Bulls Vuca Evo AM 2 started

Like the first day

Engine and gearbox: Almost 70,000 metres of altitude in a year is a brutal ordeal for the drivetrain. Even more so because I am dangerously close to the permissible total weight of 150 kilograms on my tours. However, the announcement was "endurance test" and not "children's carnival". So from July 2024 until today, I've been beating the Bulls up and down the mountains relatively mercilessly. Up to 3,200 metres, over the Scaletta, Sertig Pass and Schlappiner Joch: in terms of function and suspension, the Vuca is pretty far ahead.

>> This article provides even more information about the Bulls Vuca Evo AM 2.

The Vuca had to endure my favourite torture route - from Partenkirchen to the Osterfelder summit station - a dozen times in total: 1,300 metres of altitude at full throttle in fly mode means 58 minutes of maximum effort for the motor-gearbox unit. The Heimgarten is also a special test piece. I can hardly think of a steeper ramp than the one just before the hut. This is where the engine really comes into its own. But even more than torque, sensitivity, riding technique and a little bit of luck are crucial on such extreme uphills. Once at the top, the Pinion housing only feels warm to the touch. After a year under full load, the motor and gearbox purr like on the first day. Check! The brakes suffer much more from the weight and mileage. Physics cannot be ignored. I changed the pads every 15,000 metres, and both discs after 30,000.

>> The Bulls Vuca Evo AM 2 can also be seen as a technology demonstrator at the Deutsches Museum in Munich.

And now to the belt drive: It's 20 June 2025 and I suddenly step into the void on a steep trail in the Tannheimer Tal. I'm amazed in disbelief after the near-fall: the carbon belt has snapped. Of course, I don't have a replacement with me. So I have no choice but to go back to the start without any drive. It's just as well that no passers-by ask me how the belt works on this lonely tour.

How can a carbon belt break? Manufacturer Gates suspects that a stone got between the chainring and the belt and caused it to tear at some point. I'm no rocket scientist. But in times when mankind wants to fly to Mars, I don't think a carbon belt should be allowed to tear - otherwise it casts doubt on the carefree approach of the concept. In the days of the good old chain, you could shorten it in a minute if you wanted (or improvise a singlespeed if necessary), but in modern Pinion times you have to carry a spare belt with you on tour. So that strangers who spontaneously approach you don't laugh at you because you're cycling like Baron von Drais in 1817.

>> Pinion MGU in the BIKE reader test: What the community says about the motor-gearbox unit

How much does the Bulls E-MTB cost in continuous use?

*Based on the current used price for a model in good condition, as at 12/11/2025

>> We have listed more bikes with Pinion MGU here.

Conclusion

The innovative Vuca EVO AM 2 is packed with state-of-the-art technology. The riding characteristics are impressive. The motor-gearbox unit also worked perfectly, and the wear and tear was okay for an e-MTB in this weight class. Only the broken carbon belt overshadowed the otherwise problem-free endurance test of the Bulls. - Andreas Kern, BIKE long-term tester

• Functionality: 4/5
• Durability: 4/5
• Buy recommendation: 70%

Pro

• Suspension that is easy to swallow
• low-maintenance gearshift system,
• long-lasting battery

Contra

• High weight
• Driving performance only available via app
• Push assist lever suboptimal