Looks like a Fuel! The Fuel EX is one of the most versatile bikes in Trek’s MTB portfolio. With 150/145 mm of travel and a full 29-inch wheel setup, our test bike lines up as a classic trail bike. Change the rocker links and wheel configuration, though, and the platform stretches all the way to a long-travel mullet. Is that versatility enough to make the Fuel EX the best trail bike of 2026?

You can find an overview of this group test here: The best trail bike of 2026.

Trek Fuel EX 9.9 XO AXS Gen 7 | / Wh | 150/145 mm (f/r)
14.92 kg in size M | €8,499 | Manufacturer’s website

Baseball, BBQs, V8s and pick-up trucks. Some things are simply part of American culture. In the mountain biking world, the same goes for Trek. For decades, the bikes from Waterloo, Wisconsin, have been a familiar sight at trailheads everywhere. And few models in Trek’s range embody versatility quite like the Fuel. While the Slash enduro bike and the Session downhill bike are built with gravity in mind, the Fuel is designed to do it all, whether that is an after-work ride, an Alpine crossing or party laps in the bike park.

At 14.92 kg, the Fuel EX in our 9.9 XO AXS spec is one of the lighter bikes on test, and its €8,499 price sits slightly below the test-field average. On paper, then, it promises an appealing all-rounder with no weight penalty and no premium to pay. To find out whether it delivers on the trails around Innsbruck, the Fuel EX has to see off eleven strong rivals.

Spec and details of the Trek Fuel EX 9.9 XO AXS Gen 7

The Fuel EX looks premium from the very first glance. Dark burgundy paintwork offset by gold accents makes for one of our favourite designs in the whole test field, and the refinement holds up close: tight panel gaps around the storage compartment, high-quality badges and a wealth of colour-matched details.

Trek have got a plenty right on the functional side, too. The bolted downtube protector and equally secure shuttle guard are robust and easy to replace in case of damage. The cables are routed internally, and clamped at the ports, with additional internal guides preventing them from rattling on rough trails. Another clever feature is the 6 mm Allen key integrated directly into the rear thru-axle, which makes it easier to remove the wheel or carry out minor trailside repairs without the need for additional tools. It does rattle occasionally, though. Trek neatly seal all unused cable ports with blanking plugs on the Fuel EX. The only exception is the cable port on the chainstay for a mechanical drivetrain, which remains open and feels a little inconsistent.

The chainstay protector, clipped on and held by a small screw, does not sit particularly tightly, and the small protector between the main frame and rear end also came loose during testing. More concerning still, the bearings on our test bike began creaking audibly after just a few runs. On an otherwise high-quality package, that leaves a mark.

The storage compartment in the downtube is one of the best in the entire test field. The flush-fitting, painted cover blends almost invisibly into the frame and opens easily even in gloves. Two bags, one with a red pull loop and one with black, keep your gear organised, and a neatly finished plastic liner prevents any sharp edges inside the compartment. For those who want to carry more trail essentials, a tool mount under the top tube has room for a tube, CO₂ cartridge or multi-tool. Only larger mini pumps, such as the OneUp 100cc EDC pump, will not fit through the relatively small opening. Carbon dust inside the Fuel’s down tube is minimal. Another nice touch: Trek label every bolt on the bike with its torque setting, which makes workshop life easier.

Full control:
The SRAM MAVEN Silver A1 ranks among the most powerful brakes around and, paired with a 200 mm rotor up front, delivers plenty of stopping power even on long descents.

The spec of the Trek Fuel EX 9.9 XO AXS Gen 7 is well thought out without trying to impress with exotic components. What stands out, however, is that Trek are still using a RockShox Lyrik Ultimate fork with the older Charger 3.1 damper, even though the new Charger 3.2 version and the latest-generation Lyrik are now available. The difference is less noticeable on the trail, but on a bike costing €8,500, we’d still expect the latest generation.

The SRAM MAVEN Silver A1 brakes bite onto 200/180-mm rotors, match the braking performance of the pricier Ultimate models and rank among the most powerful stoppers on the market. A 180-mm rear rotor suffices here largely because of the MAVEN’s enormous power. Pair a less potent brake with that rotor on a trail bike this capable, and the combination would look far more questionable.

Shifting is taken care of by a SRAM XO Eagle AXS Transmission drivetrain, which relies on a direct-mount rear derailleur and shifts precisely and reliably even under load. The 175-mm Reverb AXS dropper post fitted to our size M test bike doesn’t make full use of the straight seat tube’s potential. A 200-mm dropper would fit without problems and would provide noticeably more freedom of movement on steeper trails.

The Bontrager Line Pro 30 might not be among the lightest carbon wheelset on the market, but its balanced stiffness and predictable ride feel make it an excellent match for the Fuel EX’s well-rounded character.

The wheels are paired with a MAXXIS DHF tire with MaxxGrip rubber compound up front, and a DHR II in the slightly harder MaxxTerra compound at the rear, both in EXO+ casing. While this is a solid combination for a trail bike, we recommend upgrading to a DoubleDown casing on the rear tire if you regularly ride in alpine terrain or spend a lot of time on rough trails.

Tuning tip: The straight seat tube has plenty of insertion depth. Riders with long legs can easily upgrade to a 200-mm dropper, gaining noticeably more freedom of movement on descents.

Helmet Fox Speedframe | Glasses 100% Speedcraft | Shirt Volcom Miste Stone | Pants ION Ionic LT | Knee pads Troy Lee Designs Stage | Shoes Giro Chamber TR

The geometry of the Trek Fuel EX 9.9 XO AXS Gen 7

With 460 mm reach in size M, the Fuel EX is on the longer side. Combined with the short 437-mm chainstays, this gives it a very playful feel. While the steep 78.3° seat angle positions you centrally over the bottom bracket, the 110-mm head tube is fairly average.

A practical touch is the progression chip at the lower shock mount. It lets you tune the rear suspension to your riding style in minutes, even trailside. The two positions are marked on the mount: a slightly more linear setup for greater comfort and traction, or a more progressive one with extra support and reserves for big jumps and rough, high-speed sections. We rode the Fuel EX in the Less Progression setting.

The Fuel EX brings out your playful side and makes even your home trails feel like new territory.

The Trek Fuel EX 9.9 XO AXS Gen 7 on the trail

One plus: Trek offer a detailed setup guide on their website. Less convincing are the recommended air pressures, which run noticeably high for both fork and shock and sit well above RockShox’s own figures. We ran both units around 10 psi below Trek’s recommendations, one tester going as much as 18 psi lower, and the Fuel EX felt more balanced for it.

How does the Trek Fuel EX 9.9 XO AXS Gen 7 perform on the climbs?

From the very first pedal strokes, the Fuel EX feels remarkably familiar. You’re positioned perfectly between the two 29″ wheels and immediately settle into a well-balanced riding position. The front end is comparatively low, putting noticeably more weight over the front wheel. This reliably keeps the front end down on steep climbs while also giving you plenty of precision when steering.

The Fuel EX won’t bag you any KOMs on the climbs, but it will win you over. Plenty of grip and a balanced riding position make for relaxed climbing.

The rear suspension responds sensitively on climbs and generates plenty of traction on technical ascents. It does bob a little more under pedalling, and in terms of pedalling efficiency it sits alongside the Propain Hugene 3 in the lower midfield among the non-electric bikes in this test. Even so, the Fuel EX climbs confidently for a modern trail bike, combining solid efficiency with a high level of comfort and plenty of grip. However, it can’t quite match the liveliest climbers in the test, particularly the Santa Cruz Tallboy.

How does the Trek Fuel EX 9.9 XO AXS Gen 7 perform downhill?

On the descents, the Fuel EX is one of those bikes you hop on and immediately feel at home. From the first metres of trail it inspires plenty of confidence, making it easy to keep pushing the pace. Few bikes on test are this intuitive to guide down the trail. Tight switchbacks, fast changes of direction, quick line switches: the Fuel EX answers every steering input effortlessly. Alongside the Propain Hugene 3, it ranks among the most agile bikes in the group, with only the Santa Cruz Tallboy going a step further for outright manoeuvrability.

Hero dirt? The Fuel EX rockets from berm to berm and hits the fun-factor sweet spot every time.

What’s particularly striking is that this agility comes with very little sacrifice in composure. The Trek remains impressively calm even on fast, rough and technical trails. A major reason for this is the excellent suspension, which ranks among the best-performing in this test field, and is only outperformed by a handful of competitors. The fork and rear suspension work together very harmoniously, responding sensitively to small hits while still providing good mid-stroke support and pleasantly progressive end-stroke resistance. As a result, you can actively pump the Fuel EX through rollers, generate plenty of pop out of berms and always get the feeling that there’s room to carry just a little more speed.

That makes the Fuel EX a guaranteed good time. Together with the Yeti MT, it tops the fun-factor ranking in the test field and is one of the few bikes that has you forever hunting new lines, even on trails you know inside out. Heck yeah!

Only on steep trails might many riders wish the low front end sat a little higher. Provided the fork steerer has the length to spare, a spacer under the stem sorts it easily to taste.

The Fuel EX is packed with clever details. It’s just a shame that the build quality of our test bike doesn’t live up to that standard.

Who is the Trek Fuel EX 9.9 XO AXS Gen 7 the right trail bike for?

The Trek Fuel EX is aimed at riders looking for a trail bike that works on a wide variety of trails. Thanks to the intuitive handling, excellent suspension and balanced geometry, it inspires confidence from the very first metre and delivers an exceptionally high fun factor.

Conclusions about the Trek Fuel EX 9.9 XO AXS Gen 7

The Fuel EX is one of the best trail bikes in this group test. Extremely intuitive handling, excellent suspension and a sky-high fun factor make it one of the standout all-rounders in the field, which is exactly what makes the quality issues so frustrating: creaking that set in early, plus a handful of smaller detail weaknesses. At this price in particular, that is hard to overlook, and it ultimately costs the Fuel EX a place on the podium. Look past it and you get a trail bike that delivers on almost any trail, a highlight of the test for its suspension and playful character.

For more information, visit the website of Trek.

The Test Field

You can find an overview of this group test here:
The Best Trail Bike of 2026

All bikes in test: AMFLOW PX Carbon Pro, Atherton A.130.1, Cannondale Bad Habit 1, Pivot Trailcat LT Pro X0, Propain Hugene 3 CF Ultimate, Raymon Tarok Ultimate, Santa Cruz Tallboy, Specialized S-Works Levo R, Specialized S-Works Stumpjumper 15 Evo, Trek Fuel EX 9.9 XO AXS Gen 7, Trek Fuel+ EX 9.8 XT Di2 Gen 2, Yeti MT XO.

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Words: Benedikt Schmidt Photos: Mike Hunger