You're sold on the e-bike revolution and want the capability and versatility of a mountain bike at a price that doesn't resemble the car you're trying to use less. You want bigger, better off-road adventures, and know that an e-MTB with the latest user-friendly tech is the best way to get them.
A tough yet refined aluminium frame that fully encases a long-range 500 Wh battery for sleek looks, a Bosch Performance CX (250 W, 85 Nm) motor that assists up to 25 km/h, a Bosch Purion controller, a 1x10 Shimano drivetrain and a suspension fork with lockout. Plus, Smart Wheel Sizing means riders of every size get a great fit – 29˝ wheels on larger frames, 27.5˝ wheels on smaller frames.
Our most affordable electric mountain bike comes with the same powerful Bosch motor and intuitive controller as our most expensive e-bikes, with a smaller battery and parts chosen to give you great value.
- Trek's Removable Integrated Battery (RIB) system looks great and is super user-friendly: it fully hides the battery in the frame for protection, makes it easy remove the battery without tools and lets you mount a water bottle cage
- This bike expands boundaries: the top-notch Bosch system is equally suited to commuting, recreation and a ridiculously fun time on the trails
- The Purion controller has Walk Assist and an intelligent eMTB mode that automatically delivers the right amount of power based on your terrain
- It's equipped with an external charging port for easy charging on or off the bike
- You can boost your Powerfly’s utility by adding a rack and mudguards, plus built-in wiring lets you easily install lights powered by the motor
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Smaller frames (S) have a top tube that dips down as it approaches the seat tube. This design makes for a lower standover height, which is good for shorter riders because it allows them to straddle their bike more easily. The larger frames (M and ML) have a straight top tube because taller riders with longer legs typically don’t have the same issues with standover height.
The Bosch Performance Line CX sets the standard for eMTB performance with up to 85 Nm of torque and an intelligent eMTB mode with Extended Boost that automatically adjusts the amount of assist based on the terrain.
RIB is a one-piece battery and cover with a built-in handle that can easily be removed and re-installed in the frame with no tools and no hassle. It’s the most convenient way to remove your battery for transport, security or just easier charging.
Watch the video
To see how far you can ride your electric mountain bike on a single charge, check out Bosch’s range calculator. We’ve auto-filled the variables for this bike model and the average rider, but you can make adjustments to get your most accurate estimate.
Calculate your range
This unique protection shield is lightweight yet robust, and protects the motor from rocks, logs and other trail debris.
Going for a long ride? Rack mounts make carrying accessories a breeze.
The bike is already internally wired to accept additional lights. Go to your dealer and simply have them attached to the bike and plug them in.
The right wheel size paired with your frame size gives you the perfect combination of responsiveness and control.
Our premium lightweight aluminium is continuously cold extruded and butted at multiple points, and hydroformed into sophisticated tube shapes for maximum strength and minimum weight.
Chainstay mounts make it easy to install a rear kickstand that stays out of your way and supports bikes of all sizes. No more laying or leaning.
*spec applies to all sizes unless otherwise noted
Frameset
Frame |
Alpha Platinum Aluminium, Removable Integrated Battery (RIB), tapered head tube, Control Freak internal routing, Motor Armor, Boost148 |
*Fork |
Size:
XS SR Suntour XCM 34, coil spring, preload, lockout, tapered steerer, 44 mm offset, Boost110, 15 mm thru axle, 80 mm travel |
Size:
S , M , L , XL SR Suntour XCM 34, coil spring, preload, lockout, tapered steerer, 44 mm offset, Boost110, 15 mm thru axle, 120 mm travel |
Max compatible fork travel |
120mm (XS & S: 100mm) |
Wheels
Hub front |
Formula DC-511, 6-bolt, Boost110, 15 mm thru axle |
Hub rear |
Bontrager alloy, sealed bearing, alloy axle, 6-bolt, Shimano 8/9/10 freehub, Boost148, 12 mm thru axle |
Skewer rear |
Bontrager Switch thru-axle, removable lever
|
Rim |
Bontrager Connection, double-wall, 32-hole, 20 mm width, Presta valve |
Spokes |
14 g stainless steel |
*Tyre |
Size:
XS , S Bontrager XR3 Comp, wire bead, 30 tpi, 27.5x2.35" |
Size:
M , L , XL Bontrager XR3 Comp, wire bead, 30 tpi, 29x2.30"
|
Max tyre size |
Frame: 29x2.60" or 27.5x2.8" (XS & S: 27.5x2.60") Fork: See manufacturer |
Drivetrain
Shifter |
Shimano Deore M4100, 10 speed |
Rear derailleur |
Shimano Deore M5120, long cage |
Crank |
FSA Bosch CK-220, 36T ring, 165 mm length |
Cassette |
Shimano Deore M4100, 11-46, 10-speed |
Chain |
KMC X10, 10-speed |
Pedal |
VP-536 nylon platform |
Max. chainring size |
38T |
Components
Saddle |
Bontrager Commuter Comp
|
*Seatpost |
Size:
XS , S Bontrager alloy, 31.6 mm, 12 mm offset, 330 mm length |
Size:
M Bontrager alloy, 31.6 mm, 12 mm offset, 360 mm length |
Size:
L , XL Bontrager alloy, 31.6 mm, 12 mm offset, 400 mm length |
*Handlebar |
Size:
XS , S Bontrager alloy, 31.8 mm, 15 mm rise, 720 mm width |
Size:
M , L , XL Bontrager alloy, 31.8 mm, 15 mm rise, 750 mm width |
*Grips |
Size:
XS , S , M , L , XL Bontrager XR Endurance Comp
|
Size:
XS , S , M , L , XL Bontrager XR Endurance Comp, lock-on
|
*Stem |
Size:
XS Bontrager alloy, 31.8 mm, Blendr-compatible, 7-degree, 50 mm length |
Size:
S , M Bontrager alloy, 31.8 mm, Blendr-compatible, 7-degree, 60 mm length
|
Size:
L , XL Bontrager alloy, 31.8 mm, Blendr-compatible, 7-degree, 70 mm length
|
Head set |
FSA IS-2, 1-1/8" top, 1.5" bottom |
Brake rotor |
Tektro, 6-bolt, 203 mm |
Accessories
Battery |
Bosch PowerTube, vertical, 500 wh |
Charger |
Bosch compact 2A, 100–240V, smart system |
Controller |
Bosch Purion |
Motor |
Bosch Performance CX, magnesium motor body, 250 watt, 85 Nm, 25 km/h (15.5 mph) max assist, 32 km/h for New Zealand |
Weight
Weight |
M - 23.37 kg / 51.53 lbs |
Weight limit |
This bike has a maximum total weight limit (combined weight of bicycle, rider and cargo) of 136 kg (300 lb). |
We reserve the right to make changes to the product information contained on this site at any time without notice, including with respect to equipment, specifications, models, colours, materials and pricing. The prices shown are the manufacturer's suggested retail prices.
Bike and frame weights are based on pre-production painted frames at time of publication. Weights may vary in final production.
The charts below show our recommended sizes based on height, but there are some other factors, like arm and leg length, that determine a great fit. That’s why you’ll see some overlap in our recommendations. Not every rider who’s 5´8˝, for example, will fit on the same size bike. The best way to find your perfect fit is to consult the experts at your local retailer.
137.0
- 155.0 cm
4'5.9"
- 5'1.0"
64.0
- 73.0 cm
25.2"
- 28.7"
153.0
- 166.5 cm
5'0.2"
- 5'5.6"
72.0
- 79.0 cm
28.3"
- 31.1"
161.0
- 175.0 cm
5'3.4"
- 5'8.9"
76.0
- 82.0 cm
29.9"
- 32.3"
174.0
- 188.0 cm
5'8.5"
- 6'2.0"
82.0
- 88.0 cm
32.3"
- 34.6"
186.0
- 196.0 cm
6'1.2"
- 6'5.2"
87.0
- 92.0 cm
34.3"
- 36.2"
All measurements provided in cm unless otherwise stated.
13.5 |
XS |
27.5" |
36.3 |
70.0° |
12.0 |
65.0° |
57.9 |
32.8 |
3.7 |
45.5 |
5.1 |
11.4 |
113.5 |
70.6 |
35.2 |
62.1 |
15.5 |
S |
27.5" |
39.4 |
71.5° |
13.0 |
67.6° |
59.8 |
30.7 |
4.9 |
45.5 |
4.2 |
10.1 |
112.5 |
72.1 |
39.0 |
62.3 |
17.5 |
M |
29" |
41.9 |
71.7° |
13.0 |
67.7° |
61.7 |
32.4 |
4.9 |
45.5 |
5.1 |
9.8 |
115.5 |
79.4 |
40.6 |
63.9 |
19.5 |
L |
29" |
47.0 |
71.7° |
14.0 |
67.7° |
64.1 |
32.4 |
5.0 |
45.5 |
5.1 |
9.8 |
118.0 |
81.6 |
42.7 |
64.8 |
21.5 |
XL |
29" |
52.1 |
71.7° |
16.0 |
67.7° |
67.2 |
32.4 |
5.0 |
45.5 |
5.1 |
9.8 |
121.2 |
81.8 |
45.2 |
66.7 |
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