Trek Fuel EXe 9.8

A light-assist e-MTB that keeps you involved

The Trek Fuel EXe 9.8 is a carbon full-suspension e-MTB for riders who want extra laps and easier repeat climbs without trading the lively feel of a trail bike for the heft of a full-power machine. Its TQ-HPR50 motor delivers 50 Nm, so it gives a useful helping hand rather than doing all the work for you. That suits experienced riders who enjoy picking lines, moving around the bike and arriving at the top with something left in the legs.

There is 150 mm of fork travel and 140 mm at the rear, which is a capable package for technical singletrack, rocky trail-centre descents and rough natural loops. It is not intended as a substitute for a longer-travel, full-power e-MTB used repeatedly on uplift-style days. On the right ride, though, the lower mass and more active pedalling feel are a big part of the appeal.

The newest Fuel EXe 9.8 build and older examples

The newest Fuel EXe 9.8 specification is the latest UK GX AXS T-Type build, but the 9.8 is now a legacy model rather than part of Trek's current UK Fuel EXe catalogue. That means many examples will be new old stock, ex-demo or pre-owned, and the exact build matters more than the name printed on the frame.

The latest GX AXS T-Type version combines SRAM's 12-speed GX Eagle AXS Transmission with Code Bronze four-piston brakes and a RockShox Lyrik Select+ fork using the Charger 3.1 RC damper. It has a separate 780 mm carbon handlebar and stem rather than the one-piece cockpit used on the earliest 9.8s. Its wheelset and rear shock need a closer look on each bike: later listings describe either Line Comp 30 or Line Elite 30 wheels, and either a Super Deluxe Select+ or Super Deluxe Ultimate AirWiz rear shock.

Earlier 9.8 choices remain distinct. The original GX AXS build has the earlier wireless SRAM GX Eagle drivetrain, Code R brakes, carbon wheels and an integrated 820 mm carbon cockpit. The original Shimano XT version uses mechanical 12-speed shifting and XT four-piston brakes. Mechanical XT avoids the charging routine of an electronic derailleur, while the GX AXS versions give you wireless controls; T-Type adds shifting designed to work under load. Freehub standards differ between XT, GX AXS and GX AXS T-Type bikes, so wheels are not automatically interchangeable between them.

Published size-M weights also vary by build. The original XT is the lightest published 9.8 at 18.1 kg, while the original GX AXS and later GX AXS T-Type records are approximately 18.98 kg. The difference is worth knowing if you want the easiest bike to muscle through tight turns, lift over a gate or pedal beyond the assistance limit.

Carbon chassis, 29-inch wheels and a lively trail stance

Every Fuel EXe 9.8 uses the first-generation OCLV Mountain Carbon chassis with Active Braking Pivot, a Mino Link and 29-inch wheels in every stock size. In the Low Mino Link position, the 65-degree head angle, 77-degree effective seat angle and 440 mm chainstay point towards a stable but responsive ride. The steep seated position should help on sustained climbs, while the modest rear-centre and comparatively low e-MTB weight should make the bike easier to place through turns than a heavier full-power alternative.

A low bottom bracket can help the bike feel settled in corners, but it also rewards tidy pedal timing on roots and rocks. The 150 mm Lyrik fork and 140 mm rear travel bring welcome control and traction when the trail gets rough, without turning the Fuel EXe into a long-travel plough.

The stock layout is 29 inches front and rear, with clearance for tyres up to 29 x 2.5 inches. A 27.5-inch rear wheel is compatible when the Mino Link is set to High, creating a mixed-wheel setup with more rear clearance and a more agile feel. It is an aftermarket change rather than supplied equipment, requires a compatible Boost148 rear wheel and cassette or freehub, and reduces the effective assistance cut-off by roughly 1 km/h with a 27.5 x 2.5-inch rear tyre.

Battery, assistance and longer days out

The removable 360 Wh battery helps the Fuel EXe keep its slim, trail-bike-like silhouette. Trek gives a broad planning duration of 2-5 hours, but steep climbs, winter temperatures, mud, rider weight and assistance mode can shift that figure substantially. UK assistance stops at 15.5 mph, so the bike remains a lighter proposition when you are rolling faster on road links or flatter trails.

For longer loops, the compatible 160 Wh TQ range extender adds approximately 40% more range. It costs about 900 g and occupies the bottle-cage position, so a hydration pack or hip pack makes sense on those big days. The internal battery cannot be replaced with a larger one.

Looking after a legacy light e-MTB

The carbon frame has a bottle position on every size, although size S is limited to a 20 oz bottle. There are no rack, mudguard or kickstand mounts, so this is happiest as a focused trail bike rather than a luggage-carrying commuter. Integrated lights are compatible as a retailer-installed addition, but they are not supplied with the bike.

After wet rides, clean the charge-port and battery-cover area and avoid directing high-pressure water at bearings or electrical seals. For longer storage, keep the battery above 30% charge rather than leaving it fully depleted. On an ex-demo or pre-owned example, battery health, charger inclusion, suspension servicing and pivot service history are far more important than a shiny frame.

There is scope to tune the bike rather than replace it. The frame accepts up to a 160 mm fork within its 567 mm axle-to-crown limit, and compatible air or coil rear shocks can be fitted with the correct mounting hardware. A retailer-installed TQ HPR60 conversion is technically possible and may add 10 Nm, although the Fuel EXe firmware still caps peak mechanical power at 300 W and non-warranty motor availability may be limited.