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Trek Powerfly 4

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Powerfly 4 is our most affordable electric mountain bike. It's built with parts that hold up, like a smooth-shifting Shimano drivetrain, and a powerful Bosch motor. Plus, it features our user-friendly Removable Integrated Battery (RIB) system that's fully encased in the frame yet doesn't require tools for removal. This bike expands your boundaries and lets you travel to destinations you never thought you'd reach on a mountain bike.

It's right for you if...
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 an e-MTB with the latest user-friendly tech is the best way to get them.

The tech you get
A tough yet refined aluminum frame that fully encases a long-range 500Wh battery for sleek looks, a Bosch Performance CX (250W, 75Nm) motor that assists up to 20 mph or 32 km/h, a Bosch Purion controller, a 1x10 Shimano drivetrain, an 80mm SR Suntour fork with lockout, and hydraulic disc brakes. Plus, Smart Wheel Sizing means riders of every size get a great fit—29" wheels on larger frames, 27.5" wheels on smaller frames.

The final word
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.

Why you'll love it
- 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 fenders, plus built-in wiring lets you easily install lights powered by the motor

Wheel size:
- Sizes X-Small – Small: 27.5-inch
- Sizes Medium – X-Large: 29-inch


Geometry Chart:
Frame sizeX-SmallSmallMediumLargeX-Large
Wheel size 27.5" 27.5" 29" 29" 29"
A — Seat tube (cm) 36.3 39.4 41.9 47 52.1
Effective seat tube angle 70.0° 71.5° 71.7° 71.7° 71.7°
C — Head tube length (cm) 12 13 13 14 16
D — Head angle 65.0° 67.6° 67.7° 67.7° 67.7°
E — Effective top tube (cm) 57.9 59.8 61.7 64.1 67.2
F — Bottom bracket height (cm) 32.8 30.7 32.4 32.4 32.4
G — Bottom bracket drop (cm) 3.7 4.9 4.9 5 5
H — Chainstay length (cm) 45.5 45.5 45.5 45.5 45.5
I — Offset (cm) 5.1 4.2 5.1 5.1 5.1
J — Trail (cm) 11.4 10.1 9.8 9.8 9.8
K — Wheelbase (cm) 113.5 112.5 115.5 118 121.2
L — Standover (cm) 70.6 72.1 79.4 81.6 81.8
M — Frame reach (cm) 35.2 39 40.6 42.7 45.2
N — Frame stack (cm) 62.1 62.3 63.9 64.8 66.7
Frame SizeHeight (inches)Height (cm)Inseam (inches)Inseam (cm)
X-Small 4'5.9"-5'1.0" 137-155cm 25.2"-28.7" 64-73cm
Small 5'0.2"-5'5.4" 153-166cm 28.3"-31.1" 72-79cm
Medium 5'3.4"-5'8.9" 161-175cm 29.9"-32.3" 76-82cm
Large 5'8.5"-6'2" 174-188cm 32.3"-34.6" 82-88cm
X-Large 6'1.2"-6'5.2" 186-196cm 34.3"-36.2" 87-92cm

Will my bike have a curved top tube?

Will my bike have a curved top tube?

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. Larger frames (M and up) have a straight top tube because taller riders with longer legs typically don’t have the same issues with standover height.


Motor Bosch Performance CX, magnesium motor body, 250 watt, 75 Nm
Battery Bosch PowerTube 500Wh
Display Bosch Purion Controller
Max Assisted Speed 20mph or 32km/h max assist
Charger Bosch compact 2A, 100-240V
Frame Alpha Platinum Aluminum, Removable Integrated Battery (RIB), tapered head tube, Control Freak internal routing, Motor Armor, Boost148
Fork SR Suntour XCM 34, coil spring, preload, lockout, tapered steerer, 44mm offset
Headset FSA IS-2, 1-1/8" top, 1.5" bottom
Axles Front: 12mm thru axle
Rear: 15mm thru axle
Rims/Wheels Bontrager Connection, double-wall, 32-hole, 20mm width, presta valve
Hubs Front: Formula DC-511, 6-bolt, Boost110
Rear: Bontrager Approved DC-3248, sealed bearing, alloy axle, 6-bolt, Shimano 8/9/10 freehub, Boost148
Spokes 14g, stainless steel, black
Tires Size XS, S: Bontrager XR3 Comp, wire bead, 30tpi, 27.5" x 2.35
Size M, L, XL: Bontrager XR3 Comp, wire bead, 30tpi, 29" x 2.30
Crankset FSA Bosch CK-220, 165mm length
Chainrings 36T
Chain KMC X10, 10 speed
Rear Derailleur Shimano Deore M5120, long cage
Cassette/Rear Cogs Shimano Deore M4100, 11-46, 10 speed
Shifters Shimano Deore M4100, 10 speed
Handlebars Bontrager alloy, 31.8mm, 15mm rise
Tape/Grips Bontrager XR Endurance Comp, lock-on
Stem Bontrager alloy, 31.8mm, Blendr compatible, 7 degree
Brakes Tektro HD-M275 hydraulic disc w/Tektro, 203mm, 6-bolt rotors
Pedals VP-536 nylon platform
Saddle Bontrager Commuter Comp
Seat Post Bontrager alloy, 31.6mm, 12mm offset

* Subject to change without notice.