Powerfly 4 is our most affordable electric mountain bike. It's built with parts that hold up, like a dependable 9-speed Shimano drive train, a 120 mm SR Suntour fork and a powerful Bosch Performance CX 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 that 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 trail adventures and know that an e-MTB with the latest user-friendly tech is the best way to get them.
The tech you get
A lightweight and durable Alpha Platinum Aluminium frame that fully encases a long-range 500 Wh battery for sleek looks and protection on the trail, a Bosch Performance CX (250 W, 75 Nm) motor that assists up to 25 km/h, an ergonomic Bosch Purion controller, a Shimano drive train, a 120 mm SR Suntour XCR fork with lockout and hydraulic disc brakes. Plus, Smart Wheel Sizing means you'll get the fastest wheel that fits – 29˝ wheels on larger frames, 27.5˝ wheels on smaller frames.
The final word
Our most affordable electric mountain bike is equipped with performance parts, a high-end Bosch motor, powerful battery and intuitive controller for confidence and a fun boost on trails and roads.
favorite_borderWhy 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
- It rides like a trail bike because it is one: Powerfly is built according to Trek's trail heritage with mountain bike tech developed over decades of innovation
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. 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.
New Bosch Performance Line CX
The all-new Bosch Performance Line CX motor is lighter, smaller and quieter than previous versions, for cleaner integration and more nimble handling. It’s also more efficient so you can go further on a single battery charge. Use the intelligent eMTB mode to automatically adjust the amount of assist to match the terrain. It’s a set-and-forget mode that delivers just the right amount of power so you can focus on enjoying the ride.
Bosch Purion Display
Bosch's Purion display features a fully-functional speedometer with a backlit display, service interval indicator and battery range indicator. Its thoughtful design allows riders to scroll through functions or choose the right level of support while maintaining contact with the handlebars.
Smart Wheel Size
The right wheel size paired with your frame size gives you the perfect combination of responsiveness and control.
This unique protection shield is lightweight yet robust, and protects the motor from rocks, logs and other trail debris.
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.
Going for a long ride? Rack mounts make carrying accessories a breeze.
Alpha Platinum Aluminium
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.
Wider dropouts (110mm front, 148mm rear) give you the stiffness of a 27.5" wheel with all the benefits of a 29" wheel, and Boost148 at the back lets you run wider tyres and a larger chain ring without affecting q-factor and pedalling efficiency.
*spec applies to all sizes unless otherwise noted
|Frame||Alpha Platinum Aluminium, 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, 44 mm offset, Boost110, 15 mm thru axle, 120 mm travel|
|Max compatible fork travel||120mm (XS & S: 100mm)|
|Front hub||Formula DC-511, 6-bolt, Boost110, 15 mm thru axle|
|Rear hub||Bontrager alloy, sealed bearing, alloy axle, 6-bolt, Shimano 8/9/10 freehub, Boost148, 12 mm thru axle|
|Rim||Bontrager Connection, double-wall, 32-hole, 20 mm width, Presta valve|
|*Tyre|| Size: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||29x2.60" or 27.5x2.8" (XS & S: 27.5x2.60")|
|Shifter||Shimano Altus M2010, 9-speed|
|Rear derailleur||Shimano Acera M3000, Shadow design, long cage|
|Crank||FSA 310, 15T w/chain guard, 170 mm length|
|Cassette||Shimano HG200, 11-36, 9-speed|
|Chain||KMC E9S, 9-speed|
|Pedal||VP-536 nylon platform|
|Saddle||Bontrager Arvada, steel rails, 138 mm width|
|*Seatpost|| Size: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||Bontrager alloy, 31.8 mm, 15 mm rise, 720 mm width|
|Grips||Bontrager XR Endurance Comp|
|*Stem|| Size:S , M |
Bontrager alloy, 31.8 mm, Blendr-compatible, 7-degree, 60 mm length
| Size:L |
Bontrager alloy, 31.8 mm, Blendr-compatible, 7-degree, 70 mm length
| Size:XL |
Bontrager alloy, 31.8 mm, Blendr-compatible, 7-degree, 80 mm length
|Head set||FSA IS-2, 1-1/8" top, 1.5" bottom|
|Brake||Tektro HD-M275 hydraulic disc|
|Brake rotor||Tektro, 203 mm, 6-bolt|
|Battery||Bosch PowerTube, vertical, 500 wh|
|Charger||Bosch compact 2A (100-240 V) charger|
|Motor||Bosch Performance CX, 250 Watt, 75 Nm, 25 km/h max assist|
|Weight||M - 24.47 kg / 53.95 lbs (with tubes)|
|Weight limit||This bike has a maximum total weight limit (combined weight of bicycle, rider and cargo) of 136 kg (300 lb).|
Sizing & fit
Proper bike fit is essential for best performance and comfort. Any size and geometry measurements shown on our website are for general comparison purposes only. To find your perfect fit, visit an authorised Trek retailer, where an expert skilled at sizing will help you find the appropriate bike and size for your individual needs.
153.0- 166.5 cm
72.0- 79.0 cm
161.0- 172.0 cm
76.0- 81.0 cm
165.5- 179.0 cm
77.0- 84.0 cm
177.0- 188.0 cm
83.0- 88.0 cm
186.0- 196.0 cm
87.0- 92.0 cm
All measurements provided in cm unless otherwise stated.
|Frame size number||Frame size letter||Wheel size||A — Seat tube||Effective seat tube angle||C — Head tube length||D — Head angle||E — Effective top tube||F — Bottom bracket height||G — Bottom bracket drop||H — Chainstay length||I — Offset||J — Trail||K — Wheelbase||L — Standover||M — Frame reach||N — Frame stack||Stem length|