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Trek Powerfly FS 4 Gen 3 Electric Mountain Bike


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Powerfly FS 4 Gen 3 Electric Mountain Bike

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Product ID: 1651073

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Trek Powerfly FS 4 Gen 3 Electric Mountain Bike

Trek's Powerfly FS 4 Gen 3 is a full-suspension electric mountain bike that's highly capable on the trails. The durable aluminium frame and SR Suntour fork incorporate plush suspension, providing 100/120mm of bump-absorbing travel up front and 100mm to the back. With a Bosch electric drive system, you can make the most of the descents, with pedalling assistance up to 15.5mph/25kph helping you back up to the top of the trails each time. The battery and motor are neatly integrated into the frame, while the Bluetooth LED remote and Kiox display can be paired with the eBike Flow app, for activity tracking, navigation and customisation. 

A Shimano Deore 10-speed drivetrain and Tektro hydraulic brakes with big rotors bring smooth shifting and powerful braking in all conditions. The wheels are specific to the frame size; 27.5" on the smaller sizes and 29" on the bigger bikes, creating a similar ride feel across the range. A 100mm travel dropper post allows you to move the saddle out of the way as and when required, for more control on steep drops and descents. 

Browse our range of Trek electric mountain bikes today.


  • Trek Alpha Platinum Aluminium frame
  • SR Suntour XCR 34 air spring fork with 100/120mm travel and lockout
  • Maximum compatible fork travel - 120mm (526mm axle-to-crown) (M-XL); 100mm (492mm axle-to-crown) (XS, S)
  • Bosch's new smart system gives you all the same power and responsiveness with a new Bluetooth-connected LED remote and eBike Flow app that puts even more control and customisation at your fingertips
  • The controller has Walk Assist and an intelligent e-MTB mode that automatically delivers the right amount of power based on your terrain
  • 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 to remove the battery without tools and lets you mount a water bottle cage
  • The bigger battery means you can adventure for longer between charges
  • Shimano Deore drivetrain is precise and offers a wide gear range
  • Tektro hydraulic disc brakes for all-condition stopping power
  • Frame-size specific wheels and Bontrager XR3 Comp tyres - 27.5" on the XS and S, 29" on the M - XL sizes

Battery Specification

  • Battery Weight: 3.6kg (approximate)
  • Battery Power: 625Wh
  • Charge Time: 5.4 hours

Technical Specification

Frame Trek Alpha Platinum Aluminium, Removable Integrated Battery (RIB), tapered head tube, internal routing, Motor Armour, rocker link, rack and mudguard mount, ABP, Boost148, 100mm travel
Fork SR Suntour XCR 34, air spring, LO R damper, hydraulic lockout, tapered steerer, 44mm offset, oversized crown for eMTB, Boost110, 15mm bolt-on thru-axle, 100mm travel (XS,S) / 120mm travel (S-XL)
Shock SR Suntour Edge R, 190mm x 45 mm
Stem Bontrager Comp, 31.8mm, Blendr compatible, 7-degree, 60mm length (XS,S) / 70mm length (M-XL)
Handlebar Bontrager alloy, 31.8mm, 15mm rise, 720mm width
Grips Bontrager XR Trail Comp, nylon lock-on
Front Brake Tektro HD-M275 hydraulic disc / Tektro, 6-bolt, 203mm rotor
Rear Brake Tektro HD-M275 hydraulic disc / Tektro, 6-bolt, 203mm rotor
Brake Levers Tektro
Rear Derailleur Shimano Deore M5120, long cage, 10-speed
Shift Levers Shimano Deore M4100, 10-speed
Chain KMC X10, 10-speed
Cassette Shimano Deore M4100, 11-46, 10-speed
Crankset FSA Bosch CK-220, 36T ring, 165mm length
Front Wheel Rim - Alex MD35, tubeless compatible, 32-hole, 35mm width, Presta valve / hub - Bontrager sealed bearing, alloy axle, 6-bolt, Boost110, 15mm thru-axle
Rear Wheel Rim - Alex MD35, tubeless compatible, 32-hole, 35mm width, Presta valve / hub - Bontrager alloy, sealed bearing, alloy axle, 6-bolt, Shimano 8/9/10 freehub, Boost148, 12mm thru-axle
Front Tyre Bontrager XR3 Comp, wire bead, 30 tpi, 27.5x2.35" (XS,S), 29x2.30" (M-XL), clincher
Rear Tyre Bontrager XR3 Comp, wire bead, 30 tpi, 27.5x2.35" (XS,S), 29x2.30" (M-XL), clincher
Seatpost TranzX JD-YSP18, 100mm travel, internal routing, 31.6mm, 361mm length (XS-M) / 425mm length (L-XL)
Pedals Available to be purchased separately
Motor Bosch Performance Line CX, smart system, magnesium motor body, 85Nm, 250w
Remote Bosch LED Remote, smart system
Display Bosch Kiox 300, smart system
Battery Bosch PowerTube 625Wh, smart system
Charger Bosch standard 2A, 230V, smart system
Electric Assisted Speed Limit 15.5mph / 25km/h
Maximum Weight 136kg / 300lb (combined weight of bicycle, rider and cargo)
Manufacturer Claimed Weight 21.65kg / 47.74lbs (excluding battery) (size medium)

Built, Checked, Tuned and Tested

All our bikes are fully built, checked, tuned and tested by our Cytech qualified mechanics and then securely packaged, ready for delivery. All you have to do is add the pedals (if included), attach the handlebars to the stem and tighten them following the included detailed instructions or by watching our video and using the provided FREE tools. Visit our Bike Assembly page to see how you assemble your new bike once you receive it.

All bikes collected from our shop, are built, tested and ready to ride.

Please note, occasionally, manufacturers may change the specification without notice. Bicycles do not come with pedals unless otherwise specified. Bikes ordered for delivery will not arrive with the pedals installed, please refer to the owners manual and pedal installation guides provided for guidance. We do not install accessories to bikes, including mudguards. Bikes ordered for delivery that have tubeless compatible tyres and rims will arrive with inner tubes installed or with tubeless valves installed, this will be brand dependent. Sealant is available to be purchased separately.

If you require any assistance please contact our Customer Care team.

Trek Powerfly FS 4 Gen 3 Electric Mountain Bike Sizing

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