Review: BMC Trailfox AMP Two



Construction, Features and Motor The main feature of the frame is the carbon front triangle with its giant downtube. The downtube uses a "Twin Hollow-core Tube Design." These are two complete tubes on either side which are connected across the top; the hollow opening on the underside receives Shimano's internal 504wh battery for an integrated system. The head tube junction is also huge and gives the frame distinct look, and possibly storage for a sandwich in the hollow.The swingarm is aluminum on the AMP Two and connected to the front triangle by BMC's twin-link APS (Advanced Pivot System). BMC claim they have optimized the size and shape of the links to get the perfect characteristics for eMTB riding. More pricey versions of the AMP come with a carbon swingarm which saves nearly 600grams.The motor is a standard STEPS E8000 unit that has stepped into rival Bosch in terms of MTB sales within two years of being in production. BMC (and others) claim that switching to the internal Shimano battery, they can save a bunch of weight from the frames structure, but a quick drop on the scales show the internal battery weighs 3.21kg against the 2.62kg of the internal type. Oh, there is room for a bottle cage too.
People worry about the added complexity of eMTBS, but I have not had a single issue with a Shimano motor or battery on any test bike.
Geometry & Sizing
The Trailfox AMP follows on the progressive nature of the acoustic Trailfox. My large sized test rig (unfortunately there is no XL option for taller riders) had a 469mm reach and a 620mm stack height. The head angle is set at 66º, the seat angle at 74º, and there is -17mm of bottom bracket drop. The chainstay is fairly short for an eMTB at 447mm.
Suspension Design APS stands for Active Pivot System, a design that uses a solid rear triangle connected via two short links to the front end, the upper of which drives the shock.
The suspension is also designed to be sensitive at the start of the stroke with a high leverage ratio, but progresses linearly through most of the travel, it then reduces at the end of the travel to match the ramp-up of an air shock at the end of the stroke. The anti-rise (no graph provided) is said to be around 80% throughout the travel.
Starting at the front of the Trailfox AMP, we find a cockpit taken care of by BMC's own brand components. Magura MT5 brakes with 203mm rotors, and Fox's E-Bike Optimized 36 fork is matched to a Float DPX with an EVOL air can. The wheels are taken care of by DT Swiss (who are down the road from BMC) and their Hybrid H1700 wheelset; these wheels feature a thicker wall at the spoke bed, thicker spoke heads and nipple and a steel freehub body. There's a full Shimano XT drivetrain, while RaceFace control the dropper post with a 150mm Aeffect topped with a WTB saddle.

Climbing The Trailfox AMP started each climb with the face of glee that every eMTB gives you as you cruise away from base nearly effortlessly on the road. The Shimano motor system is quieter than the Bosch, but whirs more than the near-silent Specialized/Brose setup. The bike is super stable under power and maintains its height in the travel. The geometry is commendable when attacking everything up to really steep pitches, where it could falter and start to wheelie and wander off-line. This is not a problem unique to the BMC - overall it is above average, but I feel all of the eMTB's that I've ridden so far rode could have their climbing prowess on steep sections improved massively via the geometry.It's shorter and steeper than most bikes it was ridden against, which made it slightly more nimble on the climbs to switch direction and pick a clean line. Its only real fault on the way up are its long 170mm crank arms, which took a beating on the knobbly tech in Finale - thankfully, we are seeing more and more eMTB's adopting shorter cranks. Naysayers will claim that I need to improve my pedaling and timing, but this is simply not the answer. My timing is good with a normal bike, but an eMTB will push you to challenge yourself with harder climbs more often, with higher speeds, higher cadences, and the need to keep the cranks rotating for the motor to stay engaged.
Descending After conquering some gnarly climbs that are impossible on a normal bike, it was time to check the descending capabilities of the Trailfox. The supple suspension at the start of the stroke really helped with smoothing chatter and provided great grip on cambers and flat corners. The progressive nature of the suspension also gave great mid-stroke support, as well as plenty of bottom out resistance from big hits. Being shorter and steeper than the bikes it was pitched against (Vitus e-Sommet, Specialized Kenevo, Mondraker e-Level) didn't seem to hinder its progress heading down. The slightly shorter reach than I am used to brought back physical and mental recollections of lower backache. But overall, the bike had a great balance and composed character, it is not a super long and slack beast, but the complete system's design, tune, and eMTB weight gave a much more capable ride than the numbers would suggest.In the corners, the fairly low amount of bottom bracket drop (-17mm) between the axles makes switching between directions quick and easy. It took on most corners superbly, though does lose out on fast and long corners in terms of stability compared to the longer rigs. It also seemed to generate speed well through corners and when pumping terrain, something that some eMTB's lack.One part of this bikes great handling is down to that massive downtube. Having a huge amount of stiffness here gives a confidence inspiring ride due to its directness and responsiveness between your hands and feet. Yet, the rear triangle is not super stiff which allows the rear wheel to track and trace around corners and through rough sections. Overall the Trailfox is the best all-around eMTB that I've tested to date.
Technical Report

Shimano Integrated Battery: OK, so integrated batteries are more aesthetically pleasing on a perfect side on view of an eMTB, and I understand why people want their bike to look nice. But, compared to Shimano STEPS systems using their standard external battery, the internal one is heavier, bigger (harder to carry a spare in a pack for an epic ride) and places the on/off button, charging port, and key port in the direct firing line of incoming mud. I much prefer to have the standard batteries which are also a little faster and easier to swap out and the important contact points are out of harm's way.

Shimano XT Drivetrain: Another one bites the dust. During a simple pedal up a fire road in a less than taxing situation, I had another rear derailleur and hangar explosion. eMTB motors don't sense the snapping and cut the power, so I ended up with another badly scratched chainstay, destroyed hangar, and derailleur, and spokes, and a long, heavy push to get out of the woods and home. That's the third one this year to go with no warning.

RaceFace Aeffect Dropper This was my first experience with a dropper from RaceFace. The 150mm travel Aeffect worked without issue and the remote lever fits well on the handlebar combined with the Shimano motor undercarriage lever.

Magura MT5 I've had mixed results with Magura brakes recently; most of the time the MT7 with the older style, longer lever had a great feel and modulation, but the same caliper matched with the HC3 lever which is the most expensive, adjustable, and shortest felt like trying to modulate a piece of wood. These MT5's brakes needed an extra bleed from new to stop the bite point changing with heat and took a long time to bed in.

Is this the bike for you? If the price tag of the bike isn't something that you notice too much before splashing out, then the BMC's biggest negative is already thrown out the window. If you are looking for a great eMTB all-rounder you cannot go wrong with this machine. If you are extra tall, forget it due to the lack of XL size. If you want an eMTB simply to transport you to the top of downhill tracks, then there are better options on the market.
Pinkbike's Take
bigquotes The BMC Trailfox Amp is a fantastic all-rounder that should suit the needs of the majority of eMTB riders. The price is borderline astronomical for the component package, but this is partly made up for thanks to its great ride feeling. Paul Aston

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