Trek Fuel+ EX 8
The Trek Fuel+ EX 8 is a 21.08 kg size-M aluminium mid-assist trail e-MTB with TQ HPR60 power, a removable 580 Wh battery and size-specific EX suspension layouts.
- TQ HPR60 motor: 60 Nm of smooth mid-assist support for steep climbs and repeat laps.
- 580 Wh removable battery: Charge it away from the bike and keep bigger rides on the cards.
- Adjustable suspension progression: Choose a more linear feel or firmer support for turns and compressions.
- Size-specific wheel setup: Size S gets mixed wheels, while M to XL use full 29-inch rolling speed.
- Mechanical Eagle 70 Transmission: Loaded shifting without another battery to charge.
- Four-piston stopping power: 200 mm rotors front and rear bring confident braking leverage.
Trek Fuel+ EX 8 Deals
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Bikesy's Verdict
The Trek Fuel+ EX 8 is an appealing choice for the trail rider who wants a longer, more climb-friendly day out without losing the active feel of a conventional mountain bike. Its quiet TQ HPR60 assistance, removable 580 Wh battery, adjustable suspension progression and powerful four-piston brakes make a convincing package, while mechanical Eagle 70 Transmission keeps ownership refreshingly straightforward. The size S mixed-wheel layout is a particularly thoughtful touch for shorter riders. At 21.08 kg in size M it is not a bike for frequent carrying, and very aggressive riders may eventually want a more controlled fork and tougher tyres. For broad UK trail riding, though, the Fuel+ EX 8 has a lot of useful ability and a pleasingly unfussy character.
Pros
- Natural, quiet TQ HPR60 assistance with 60 Nm of torque
- Removable 580 Wh battery makes charging away from the bike straightforward
- Adjustable suspension progression gives the EX setup two distinct ride moods
- Size S gets a genuinely tailored mixed-wheel, 150 mm rear-travel configuration
- Mechanical Eagle 70 Transmission and four-piston brakes suit hard-working trail use
Cons
- At 21.08 kg in size M, it is cumbersome for stairs, lifting and long unassisted riding
- The stock fork and tyre casings are less suited to repeated very steep, rocky impacts
- Pedals and the compatible Range Extender are extra purchases
The Trek Fuel+ EX 8 is a full-suspension electric trail bike for the rider who wants to turn a long, climb-heavy loop into a proper afternoon out rather than an exercise in rationing energy. Its TQ HPR60 system delivers meaningful assistance without chasing the shove of a full-power e-MTB, so you still have plenty of say in how the bike rides. It suits intermediate and experienced riders particularly well, but a progressing rider can get a lot from its balanced chassis with the suspension set up properly.
Compare current Trek Fuel+ EX 8 prices
The current UK model is the Fuel+ EX 8 Gen 2, with an original UK RRP of £5,000. It is Trek's aluminium, mechanically shifted Fuel+ EX build, sitting below the carbon Fuel+ EX 9.7 and higher-specification 9.8 and 9.9 models. The specification is aimed at riders who would rather put their budget into a capable frame, substantial battery and dependable trail kit than pay for electronic shifting or a premium carbon chassis.
There is one current UK component build. It combines a 150 mm Fox Rhythm 36 fork, Fox Performance Float X rear shock, SRAM DB 8 four-piston brakes and mechanical SRAM Eagle 70 Transmission. Pedals are not supplied, so factor in a suitable flat or clipless pair from the outset.
What is the latest Trek Fuel+ EX 8?
Fuel+ EX 8 Gen 2 is the latest version, based around the TQ HPR60 motor and a removable 580 Wh battery. The motor produces 60 Nm, with 300 W maximum continuous rated power and 350 W peak power. It is a mid-assist system rather than a maximum-thrust e-MTB motor, which will appeal if you want help over rooty climbs and on repeat laps while keeping a more rider-led feel.
The battery can be removed for charging away from the bike, handy when your storage spot is nowhere near a socket. A full charge takes roughly three to four hours, making overnight charging or a recharge between rides practical. Keep some reserve for the final hills: motor output reduces below 10% charge, so an empty-battery finish is best avoided on a route with a demanding ride home.
Fuel+ Gen 2 frame, sizing and trail character
Its Alpha NEXT Platinum aluminium frame uses Trek's Active Braking Pivot suspension layout, internal routing, frame protection and adjustable suspension progression. That progression adjustment lets you choose between a more linear setup that uses travel readily and a more progressive response with greater support through compressions and turns. In an off.road.cc test, Liam Mercer found those settings made a genuinely noticeable difference to the bike's character.
The standard EX arrangement is designed for technical climbs, natural singletrack, trail-centre laps and controlled descending, rather than being the platform's longest-travel gravity option. The 64.5-degree head angle on M to XL, planted chassis and steep seating position should make it a persuasive companion on awkward uphill sections, while the rear suspension is intended to keep traction working rather than bobbing you about.
Size matters more than usual here. Size S is supplied with a 29-inch front wheel and 27.5-inch rear wheel, plus 150 mm of rear travel. Sizes M, L and XL use 29-inch wheels at both ends and 145 mm rear travel. The smaller bike's MX arrangement improves proportional fit and rear-wheel clearance for shorter riders, so it is not simply the same bike in a smaller frame.
The Fuel+ Gen 2 platform does leave room to change direction later, but these are proper conversions rather than a quick workshop tweak. Moving an M to XL bike to MX needs an MX rocker link, MX lower shock mount, 27.5-inch rear wheel, compatible 160 mm fork setup and an e-system update. An LX conversion needs an LX rocker, a 65 mm-stroke shock configuration and a compatible 170 mm single-crown fork. Buy the stock EX setup if balanced trail riding is the priority, then regard MX or LX as supported but involved future projects.
SRAM Eagle 70 Transmission is mechanical, cable-actuated 12-speed shifting rather than wireless AXS. It can shift under e-MTB load without adding a derailleur battery to your charging routine, which is a welcome bit of simplicity for wet British riding. It still needs the normal cable, chain and cassette care, especially after muddy miles. Light chain contact with the chainstay guard in the 10T sprocket can be normal, and the guard is a replaceable wear item.
UK maintenance, battery care and sensible upgrades
The claimed weight is 21.08 kg in size M with tubeless sealant and no inner tubes, so this is not a bike you will enjoy carrying up several flights of stairs or pedalling far with assistance switched off. Removing the battery can make handling it easier for storage or loading, and car-rack limits are worth keeping in mind.
The supplied 580 Wh battery is enough to support substantial rides, but no fixed mileage figure can account for climbing, rider mass, temperature, tyre choice and assistance level. A compatible TQ Range Extender can add riding time, although it is aftermarket equipment and occupies the bottle-cage area. Every frame size can carry a bottle, with more space available as frame size increases.
The stock tyres are tubeless ready and should serve broad trail use well. Riders regularly hitting sharp rocks at speed, especially heavier or more aggressive riders, may find a tougher rear casing a sensible first change. The Fox Rhythm 36 is well matched to ordinary trail duties, though the independent test found it less controlled on especially steep ground. Correct air pressure and rebound setup should come before spending money on a fork upgrade.
How Fuel+ Gen 2 differs from the previous Fuel EXe
The previous Fuel EXe generation is a separate predecessor platform, not another current Fuel+ EX 8 build. Fuel+ Gen 2 moves from the earlier HPR50 system to HPR60, raising torque to 60 Nm and using a 580 Wh battery. It also brings the configurable EX, MX and LX frame system, more dropper-post insertion and more room for bottles, range extenders and reservoir shocks. For a buyer choosing between a current Fuel+ EX 8 and an older Fuel EXe, those are meaningful differences in assistance, battery capacity and frame adaptability.
Key Features & Benefits
- Aluminium Fuel+ Gen 2 chassis: The Alpha NEXT Platinum aluminium frame brings a removable battery, Active Braking Pivot suspension, internal routing and replaceable rocker links to a robust trail e-MTB package.
- EX suspension arrangement: A 150 mm Fox Rhythm 36 fork and Float X shock target technical climbs, flowing trail-centre laps and composed descending without turning the bike into a long-travel gravity machine.
- Progression adjustment: Changing the leverage-rate setting can make the rear end more willing to use travel or more supportive through hard compressions, giving the same bike useful scope across different riding days.
- Thoughtful smaller-size configuration: The S frame pairs a 29-inch front wheel with a 27.5-inch rear, 150 mm rear travel and a curved top tube to improve clearance and proportions for shorter riders.
- Supported future flexibility: MX, LX, angle-adjust headset and AXS Transmission upgrade routes exist, although the bigger wheel and travel changes need the correct parts rather than a simple adjustment.
Geometry
Fuel+ Gen 2 EX geometry
| Size | Wheel size | Reach | Stack | Effective top tube | Head angle | Seat angle | Chainstay | Wheelbase | Standover |
|---|---|---|---|---|---|---|---|---|---|
| S | 29-inch front/27.5-inch rear | 431 mm | 624 mm | 559 mm | 64.6 degrees | 78.2 degrees | 441 mm | 1200 mm | 754 mm |
| M | 29-inch front/29-inch rear | 460 mm | 624 mm | 589 mm | 64.5 degrees | 77.8 degrees | 444 mm | 1232 mm | 746 mm |
| L | 29-inch front/29-inch rear | 485 mm | 638 mm | 613 mm | 64.5 degrees | 77.3 degrees | 444 mm | 1258 mm | 743 mm |
| XL | 29-inch front/29-inch rear | 510 mm | 651 mm | 651 mm | 64.5 degrees | 76.9 degrees | 447 mm | 1298 mm | 753 mm |
Additional published measurements
| Size | Seat tube | Head tube | Bottom bracket height | Bottom bracket drop | Fork offset | Trail |
|---|---|---|---|---|---|---|
| S | 370 mm | 110 mm | 339 mm | 34 mm | 44 mm | 129 mm |
| M | 400 mm | 110 mm | 339 mm | 35 mm | 44 mm | 129 mm |
| L | 420 mm | 125 mm | 339 mm | 35 mm | 44 mm | 129 mm |
| XL | 455 mm | 140 mm | 339 mm | 35 mm | 44 mm | 129 mm |
Alternatives to Consider
The Canyon Spectral:ONfly CF 8 is a close light e-trail alternative for riders weighing motor character, battery capacity, frame material and fork specification. The Trek brings an aluminium Fuel+ Gen 2 frame, a removable 580 Wh battery and a size-specific EX configuration, including the mixed-wheel S option.
The Propain Sresh SL is a carbon-framed alternative using the same TQ HPR60 motor. That makes it relevant if a carbon frame is high on your list, while the Fuel+ EX 8 makes its case with its aluminium chassis, mechanical Eagle 70 Transmission and adjustable EX suspension platform.
Reviews
In an independent off.road.cc test of the Fuel+ EX 8 Gen 2, Liam Mercer praised the natural, quiet assistance, planted climbing balance and predictable cornering. The rear suspension was described as supple and traction-rich, and the progression adjustment was found to create meaningfully different ride characteristics rather than a token change.
On descents, the review found the bike confident for ordinary trail riding, with the more linear setting encouraging travel use and the progressive setting adding support in turns and compressions. It also identified two useful limits for harder chargers: the Rhythm 36 fork felt less controlled on very steep ground, while stronger tyre casings would be welcome for repeated rocky impacts.
Full Specification
Fuel+ Gen 2 EX platform
| Specification | Details |
|---|---|
| Platform | Fuel+ Gen 2, stock EX configuration |
| Frame | Alpha NEXT Platinum aluminium full-suspension frame with removable battery, ABP suspension, UDH, internal routing, replaceable rocker links and lower shock mounts, frame guards and adjustable suspension progression |
| Wheel format | S: 29-inch front and 27.5-inch rear. M-XL: 29-inch front and rear |
| Maximum published tyre width | 2.5 inches/63.5 mm for 29-inch tyres |
| Axles | Boost110 front and Boost148 rear thru-axles |
| Drivetrain interface | UDH/Full Mount rear interface, TQ mid-drive with ISIS crank interface and 55 mm chainline |
| Dropper-post diameter | 34.9 mm |
| Routing | Internally routed hoses and cables |
| Bottle capacity | S: 620 ml maximum. M-L: 769 ml maximum. XL: 1005 ml maximum |
| Range Extender compatibility | Compatible with an aftermarket Range Extender |
| System weight limit | 136 kg combined bicycle, rider and cargo |
Current Fuel+ EX 8 Gen 2 build
| Specification | Details |
|---|---|
| Original UK RRP | £5,000 |
| Fork | Fox Rhythm 36 with Float EVOL air spring, GRIP damper, 44 mm offset and 150 mm travel |
| Rear shock | Fox Performance Float X, two-position damper, 205 mm x 60 mm |
| Drivetrain | Mechanical SRAM Eagle 70 T-Type 1x12 |
| Shifter | SRAM Eagle 70 mechanical 12-speed |
| Rear derailleur | SRAM Eagle 70 T-Type Full Mount |
| Chainset | SRAM Eagle 70, 160 mm, with 32T T-Type alloy chainring |
| Cassette | SRAM Eagle XS-1270 T-Type, 10-52T, 12-speed |
| Chain | SRAM Eagle 70 T-Type, 12-speed |
| Brakes | SRAM DB 8 four-piston hydraulic brakes |
| Rotors | 200 mm six-bolt front and rear |
| Rims | Bontrager Line TLR 30, tubeless ready, 28-hole |
| Front hub | Bontrager sealed-bearing Boost110, 15 mm thru-axle |
| Rear hub | Bontrager sealed-bearing Rapid Drive 108, Shimano freehub, Boost148, 12 mm thru-axle |
| Spokes | 14-gauge stainless steel |
| Tyres | Bontrager Brevard Pro XR, Tubeless Ready, dual compound, 60 tpi, 2.50 inches |
| Handlebar | Race Face Turbine alloy, 35 mm clamp, 40 mm rise, 780 mm width |
| Stem | Bontrager Elite, 35 mm clamp, zero-degree, 45 mm |
| Headset | FSA Orbit ZS; compatible with aftermarket angle-adjust cups |
| Grips | Trek Line Comp lock-on |
| Seatpost | Bontrager Line Dropper MaxFlow, 34.9 mm, size-specific travel |
| Saddle | Bontrager Verse Short with stainless-steel rails |
| Pedals | Not included |
| Drive system | TQ HPR60, 60 Nm, 300 W maximum continuous rated power and 350 W peak power |
| Battery | Removable 580 Wh battery |
| Display and connectivity | LED display, Bluetooth and ANT+ connectivity |
| Charger | 4A charger |
| Claimed weight | 21.08 kg in size M with tubeless sealant and no inner tubes |
Size-specific configuration
| Size | Fork travel | Rear travel | Shock configuration | Link and lower mount | Wheel size | Dropper travel | Crank length | Handlebar width | Stem length | Front rotor | Rear rotor | Other differences |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S | 150 mm | 150 mm | Fox Performance Float X, 205 mm x 60 mm | MX rocker link and MX lower shock mount | 29-inch front/27.5-inch rear | 150 mm | 160 mm | 780 mm | 45 mm | 200 mm | 200 mm | 410 mm-long dropper, slightly curved top tube and 620 ml maximum published bottle capacity |
| M | 150 mm | 145 mm | Fox Performance Float X, 205 mm x 60 mm | EX rocker link and EX/LX lower shock mount | 29-inch front/29-inch rear | 170 mm | 160 mm | 780 mm | 45 mm | 200 mm | 200 mm | 450 mm-long dropper and bottle compatibility up to 769 ml |
| L | 150 mm | 145 mm | Fox Performance Float X, 205 mm x 60 mm | EX rocker link and EX/LX lower shock mount | 29-inch front/29-inch rear | 200 mm | 160 mm | 780 mm | 45 mm | 200 mm | 200 mm | 515 mm-long dropper and bottle compatibility up to 769 ml |
| XL | 150 mm | 145 mm | Fox Performance Float X, 205 mm x 60 mm | EX rocker link and EX/LX lower shock mount | 29-inch front/29-inch rear | 200 mm | 160 mm | 780 mm | 45 mm | 200 mm | 200 mm | 515 mm-long dropper, bottle compatibility up to 1005 ml and 447 mm chainstay |