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The Powerfly FS+ 4 800W is a full-power full suspension electric mountain bike for alpine adventures, featuring a powerful Bosch motor and massive 800 Wh battery.
The Powerfly FS+ 4 800W is a full-power full suspension electric mountain bike for alpine adventures, featuring a powerful Bosch motor and massive 800 Wh battery.
Trek

Trek Powerfly FS+ 4 800Wh Gen 4 E-Mountain Bike in Mercury/Dark Web

£4,150.00
Pre-Order

With Pre-Order, you can purchase the latest items added to our store in advance of them arriving with us.

Your Pre-Order is prioritised (at no additional charge); meaning that as soon as the product arrives with us, we can wrap it straight back up; ready for collection via Click & Collect or despatch to you — it often never even hits the stock room shelves!

Pre-Launch

With Pre-Launch, the date when we expect to receive the product ourselves is still a little too hazy to be confident in accepting Pre-Orders.

So, instead, you can submit your email address against the item you are interested in and we will email you as soon as stock arrives on the system.

Estimated Delivery & Collection Dates

Estimated Delivery & Collection Dates are given on Pre-Order and Pre-Launch products. They are for indication purposes only and can change at any time without notice.

The dates we provide are based on indications given by our suppliers. Whenever we get updated information from our suppliers we will endeavour to update the Estimated Delivery & Collection Dates provided on product pages.

We estimate this will be ready for despatch to you or collection via Click & Collect on Undetermined

Hassle free returns

Returns from Gateway Cycles

Returns

In the unlikely event that you are dissatisfied with your purchase from our website,please feel free to return your goods within 14 days of the purchase date for a full exchange or refund. Any item (excluding food and underwear) can be returned to us for any reason provided it is returned in ‘showroom condition’, with its original packaging, tags and a valid receipt/delivery note.

It is your responsibility to ensure that the item is returned to us in a safe and secure manner, and in the event of a refund or exchange, in saleable condition (in original packaging and including all warranty, cards, manuals and accessories).

Customers are accountable for return shipping charges.

Return Items by Post

  1. You should always keep proof of postage and we advise you to use a ‘signed for service’ when returning goods.
  2. Send your package using a recorded delivery method (always keep a copy of your receipt!) to the following address:

Gateway Cycles
5-9 Brecon Road
Abergavenny
Monmouthshire
NP7 5UH

Wrong size or you don't like the item?

If returning items that are not suitable for either refund or exchange you are accountable for the delivery cost in returning it to us. You should always keep proof of postage and we advise you to use a ‘signed for service’ when returning goods.

New faulty items/ Wrong Item Received

If you have received items that are faulty or not what you ordered send them back to us (using the steps above) and we will cover the delivery cost of the return if it is within 30 days of delivery. If we have supplied the correct product, it is not faulty or it is outside of the 30 days we can not be liable for your postage charges. You should always keep proof of postage and we advise you to use a ‘signed for service’ when returning goods.

In the event that you have received items that are faulty or not what you ordered, please send them back to us as soon as possible. Only in these cases will we cover the cost of the return shipping charges.We will refund within the cost of the item and postage within the 30 days if the item is returned within 30 days .

Faulty Items

If you have received items that are faulty please send them back to us using the steps above. Please include a covering letter describing the fault and if you would like the item replacing or refunding. Once the item arrives back at our Mail Order Centre you will receive an email notifying you about the progress. Faulty items are then forwarded onto the suppliers to confirm the warranty issue. Please be patient with us as we need to receive this confirmation from the suppliers before we can process your request for a replacement/refund.

When returning the item please use Royal Mail1stClass Recorded* so that you have a tracking reference just in case! If your item arrived faulty we will refund your postage cost. If the item was in full working order at the time of delivery to you, we can not refund your return postage cost.

*In the event that you return a faulty/incorrect item we will refund your postage charge as long as it is 1stClass Recorded or a lesser value service. We do not refund premium services.

Refunds

Refunds will be processed using the same method of payment used for the original purchase. Credit and debit card refunds must be made to the card used for the original transaction,chequepayments will be refunded in cash but due to banking restrictions can only be refunded at least 14 days after the original purchase date. Due to the high incidence of fraud we regret that we are unable to offer any refund without a valid receipt/delivery note.

Refunds will be made for faulty or incorrect items, including any delivery charge incurred by the buyer (excluding ‘Special Delivery’) in the return of the item. If the products you ordered are delivered to you in good condition but you wish to return them for any reason we will refund the full value of the goods excluding any carriage charge upon receipt of your returned goods.

Items won’t be considered lost until after 15 working days of items beingdispatched. Once the 15 working days are up we will issue a refund or replacement.

Not received your order?

If you have not received your order please call us on 01873 858519 and a member of staff can confirm the shipping date. Unfortunately we cannot consider an item to be lost until 15 working days has passed (according to Royal Mail procedure). Once the 15 working days have passed we will be able to issue a full refund or resend your order.

Trek Powerfly FS+ 4 800Wh Gen 4 E-Mountain Bike in Mercury/Dark Web

Season:2026

Brand:Trek

Code:57351GRY

The Powerfly FS+ 4 800W is a full-power full suspension electric mountain bike designed for alpine adventures, offering a powerful boost for soaring up climbs.

Its powerful Bosch motor provides assistance for climbing, while a massive 800 Wh battery ensures longevity for your longest adventures. A RockShox suspension package (120 mm rear, 130 mm front) smooths out rough trails, and a 10-speed Shimano CUES drivetrain delivers clean shifts for any kind of trail. The Powerfly FS+ provides the powerful boost needed on high alpine climbs, confident comfort on descents, and a large battery for extended range.

The Bosch Performance Line CX motor delivers plenty of torque for steep, punchy climbs and is easy to control with the Purion 200 remote. You can customise it in the eBike Flow app. The RIB 2.0 Removable Integrated Battery is a one-piece battery and cover with a built-in handle that can easily be removed and re-installed in the frame without tools. This makes it convenient for transport, security, or easier charging. With the Bosch eBike Flow app, you can increase torque to 100 Nm and peak power up to 750W. The bike is compatible with Bosch PowerMore booster batteries, which can be retrofitted by the dealer.

The Bosch Smart System LED Remote allows you to easily change assist modes, activate walk mode, or turn on optional lights. The bright LEDs are easy to see and show your battery level and assist mode at a glance. The Bosch Kiox 300 is a tough, compact, and easy-to-read full-colour display, showing ride data such as rider power, motor output, speed, and remaining range.

Starting in 2024, Trek began removing high-emission aluminium from manufacturing and replacing it with low-emission aluminium made with renewable energy. By October 2025, nearly every alloy bike made, including this one, had made the switch, driving a major drop in the footprint.

Features:

  • Bosch Performance Line CX motor 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.
  • The new eBike Flow app turns your ride into a personalised experience, allowing customisation of the motor's assist behaviour, tracking of ride stats, and integration with apps like Strava and Apple Health.
  • Shimano CUES offers a new foundation for versatility and durability, featuring Shimano’s LINKGLIDE drivetrain technology for significantly increased life on wear items like chain, cassette, and chainrings.
  • LINKGLIDE technology is engineered for incredible durability while delivering smooth and decisive shifting.
  • The Powerfly Equipped provides maximum utility thanks to pre-installed accessories including a kickstand, front and rear lights, mudguards, and a rear rack custom made for clean integration.
Technical Information
  • Frame
    Alpha Platinum Aluminium, Removable Integrated Battery (RIB 2.0), tapered headtube, guided internal routing, Motor Armor, angle-adjust headset, Mino Link adjustable geometry, adjustable leverage rate, 34.9 mm seat tube, ABP, UDH, rack and mudguard mounts, Boost 148, 120 mm travel
  • Fork
    RockShox Recon Silver, Solo Air spring, Motion Control damper, lockout, tapered steerer, 42 mm offset, Boost110, Maxle Stealth, mudguard mounts, 130 mm travel
  • Shock
    RockShox Deluxe Select R, 210x50 mm
  • Hub front
    Shimano TC500 alloy, CentreLock, 110x15 mm thru axle
  • Hub rear
    Shimano TC500 alloy, CentreLock, 148x12 mm thru axle
  • Skewer rear
    Bontrager Switch thru axle, removable lever
  • Rim
    Size: S, M, L, XL Bontrager Line TLR 30, Tubeless-Ready, 28-hole, Presta valve; Size: S, M, L, XL Bontrager Line TLR 30, Tubeless-Ready, 32-hole, Presta valve
  • Spokes
    14 g stainless steel, black
  • Tyre
    Size: S Bontrager Gunnison Pro XR, Tubeless-Ready, wire bead, 60 tpi, 27.5x2.40"; Size: M, L, XL Bontrager Gunnison Pro XR, Tubeless Ready, dual compound, aramid bead, 60 tpi, 29x2.40"
  • Tyre part
    Bontrager TLR sealant, 180 ml/6 oz
  • Rim strip
    Bontrager TLR
  • Max tyre size
    Frame: 29x2.50" (S: 27.5x2.50"), Fork: see manufacturer
  • Battery
    Bosch PowerTube 800 Wh, smart system
  • Charger
    Bosch standard 2A, 230V, smart system
  • Computer
    Bosch Purion 200
  • Motor
    Bosch Performance Line CX, 20 mph / 32 km/h max assist (25 km/h max assist in EU and APAC)
  • Shifter
    Shimano U6000, 10-speed
  • Rear derailleur
    Shimano CUES U6000 GS
  • Crank
    FSA Bosch CK-220, 36T ring, 165 mm length
  • Chainring
    FSA, 36T, steel
  • Cassette
    Shimano CUES LG300, LINKGLIDE, 11-48, 10-speed
  • Chain
    Shimano LG500, 9/10/11-speed
  • Pedal
    VP-536 nylon platform
  • Max. chainring size
    1x: 38T
  • Saddle
    Bontrager Verse P3, steel rails
  • Seatpost
    Size: S Bontrager Line Dropper, 100mm travel, MaxFlow, internal routing, 31.6 mm, 310 mm length; Size: M, L, XL Bontrager Line Dropper, 170 mm travel, MaxFlow, internal routing, 31.6 mm, 450 mm length
  • Handlebar
    Bontrager Comp, alloy, 31.8 mm, 40mm rise, 780 mm width
  • Grips
    Size: S, M, L, XL Bontrager XR Trail Comp, nylon lock-on; Size: S, M, L, XL Trek Line Comp, nylon lock-on
  • Stem
    Bontrager Comp, 31.8 mm, Blendr compatible, 7-degree, 50 mm length
  • Head set
    FSA IS-2, 1-1/8" top, 1.5" bottom
  • Brake
    Tektro Gemini SL 4 piston hydraulic brake
  • Brake rotor
    Tektro, CentreLock, 203 mm
  • Rotor size
    Max brake rotor sizes – Frame: 220 mm, min 180 mm, Fork: see fork manufacturer
  • Mudguard
    Trek custom mudguard
  • Weight limit
    This bike has a maximum total weight limit (combined weight of bicycle, rider and cargo) of 136 kg (300 lb).
Sizing Information
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