Trek Top Fuel 9.9 XX1 AXS – In our 2022 downcountry group test (2024)

The Trek Top Fuel is a true XC classic – but that’s about to change! The Trek Top Fuel 9.9 XX1 AXS 2022 drifts into the new season with more travel, a more aggressive geometry and robust components. Does this make it the perfect downcountry bike?

For an overview of the test fleet head to the group test: The best downcountry bike of 2022 – 6 models in review

Same DNA, same key elements, different focus. For 2022, Trek redesigned the Top Fuel from the ground up, clearly shifting the focus from XC to trail riding and downcountry. The latest incarnation of Trek’s XC-classic retains all the well-proven features of its predecessor and combines them with some exciting new ones. While the € 12,099 Trek Top Fuel 9.9 XX1 AXS still rolls on 29″ wheels, Trek have bumped up the travel of the rear suspension from 115 to 120 mm and paired it with 120 mm at the front. Moreover, Trek have finally gifted their timeless classic with a storage compartment in the down tube, which can be found on many of their gravity-oriented bikes – now you can leave your backpack or hip-pack at home and store all your trail essentials in the small bag under the bottle cage. The new Top Fuel also features Trek’s proprietary Knock Block in the headset, which limits the steering angle and prevents the fork from damaging the frame during a crash. On the trail, the system doesn’t affect the handling in any way. A large TPU plate protects the down tube against stray rocks and a reasonably sized and well-positioned chainstay protector prevents chain slap and paint chips. The few remaining cables are neatly routed inside the frame, ensuring a clean look while the unused cable ports are sealed with rubber plugs.

The spec of the Trek Top Fuel 9.9 XX1 AXS

For the spec of the Top Fuel 9.9 XX1 AXS, Trek rely on a mix of components from SRAM and their own component brand Bontrager. Let’s start from the RockShox Ultimate suspension: the SID Ultimate fork features RockShox’s new Charger RaceDay damper with a lockout lever on the top of the right leg, while Trek’s ABP (Active Braking Pivot) rear suspension is controlled by a Deluxe Ultimate shock, also with a lockout lever. Together with the Specialized, the Top Fuel is the only bike in this test without a bar-mounted lockout remote, which, in combination with the wireless AXS components, ensures a super-tidy look. Thanks to its wireless components, the Top Fuel has only two cables: the brake lines of the SRAM G2 Ultimate four-piston brakes – we’re waiting impatiently for some wireless brakes ;). The G2 Ultimate model is the top-of-the-line version of SRAM’s trail-specific stoppers, which deliver the same excellent performance as the RSC model and save a few extra grams thanks to their carbon lever blades and titanium bolts. Trek combine a 180 mm rotor at the front and a smaller 160 mm one at the rear.

An electronic SRAM XX1 AXS drivetrain ensures smooth and precise shifting while the UDH mech hanger is easy to find and quick to replace. Even the 150 mm Reverb AXS dropper post doesn’t require a cable, ensuring super-fast and precise operation. That’s a must with downcountry bikes because you’re constantly swapping between climbs and descents. The one-piece Bontrager RSL carbon co*ckpit also contributes to the clean look of the Top Fuel, with the handlebars and stem joined together in a single carbon piece. That being said, the 820 mm handlebars are extremely wide and the one-piece design doesn’t allow for fine-tuning, except for the stem height that can be changed using spacers. We recommend cutting down the handlebars, although this will result in a stiffer co*ckpit. Trek also rely on their in-house components for the wheels, pairing Bontrager Line Pro 30 carbon rims with 2.4″ Bontrager XR4 Team Issue tires. The aggressive tread pattern and soft rubber compound ensure excellent traction while rolling resistance is only marginally higher than with a shallow-profiled XC tire and noticeable only on hardpack terrain. That being said, we’d choose more grip over lower rolling resistance all day long! While at 12.2 kg, the Top Fuel is the heaviest bike in the entire test field, it can easily keep up with the competition uphill. This is also made possible by the spec, which at the same time adds to the excellent trail performance of the Top Fuel.

The geometry of the Trek Top Fuel 9.9 XX1 AXS

With five available sizes, S to XL, there should be a suitable Top Fuel for everyone measuring between 153 and 196 cm. Our test bike in the intermediate size M/L has 465 mm reach, 600 mm stack height and a short 435 mm seat tube, which, together with the generous insertion depth, allows you to insert the dropper post all the way into the frame. Not only does this ensure excellent freedom of movement on the bike, but also lets you choose the frame size based on your desired reach. A flip chip in the shock mount allows you to switch between the high and low settings and adapt the geometry of the bike to your needs and preferences. In the high setting, the head and seat tube angle are 0.4° steeper, the chainstays 1 mm shorter and the bottom bracket 5 mm higher. Needless to say, the changes also alter the reach, stack height and wheelbase of the Top Fuel. As usual, we rode the bike mostly in the low setting, which is your best option for trail riding.

The Trek Top Fuel 9.9 XX1 AXS 2022 impresses with its clean look, clever details and harmonious spec.

The Trek Top Fuel 9.9 XX1 AXS on the trail

Together with the Specialized Epic EVO, the Trek Top Fuel 9.9 XX1 AXS is the only bike in this test without a bar-mounted lockout remote – and actually the only one that doesn’t need one! Already after the first few meters, it becomes clear that the suspension is stiff and, above all, extremely efficient, even in fully open mode. Moreover, the pedalling position is very comfortable, with the weight evenly distributed between the hands and saddle, making the Trek suitable for long rides. Going uphill, the rear suspension generates sufficient traction, even on loose trail sections with slippery roots and with the shock in open mode. While your mates are still fiddling around with the climb switch, you’re already blasting up the side of the mountain onboard the Trek Top Fuel! However, tall and long-legged riders should push the saddle all the way forward to prevent the front wheel from lifting on steep climbs.

The Trek Top Fuel 9.9 XX1 AXS does not need a lockout at all and convinces in both uphill and downhill with a progressive yet traction-strong rear end.

Downhill, the ultra-wide handlebars have their pros and cons, on the one hand, inspiring lots of confidence and providing additional stability in fast trail sections, on the other, requiring great precision to squeeze through narrow trees. Like the Specialized, the Trek is intuitive and easy to ride, with the weight evenly distributed between the front and rear wheel. Downhill, the rear suspension generates plenty of traction and provides excellent mid-stroke support while offering sufficient reserves for rowdy trail sessions. Too often we caught ourselves ploughing through nasty root carpets and tall berms at Mach 10, but here the precise and intuitive handling inspires huge amounts of confidence and ensures top riding fun.

Tuning tips: tall and long-legged riders should push the saddle all the way forward | cut off the handlebars or swap the co*ckpit for a narrower one

Conclusion

Not only does the Trek Top Fuel 9.9 XX1 AXS 2022 impress with its clean look, clever details and harmonious spec, but also delivers an impressive performance on the trail. The drive-neutral, rear suspension is incredibly efficient and generates plenty of traction, even with the shock in fully open mode. At the same time, the intuitive handling and progressive rear suspension put a huge smile on your face. Whether it’s an agonising lactate battle, quick post-work spin or epic singletrack adventure, the Top Fuel delivers! As a result, the Trek Top Fuel 9.9 XX1 AXS 2022 secures Best in Test in our 2022 downcountry group test.

You can find out more about at trekbikes.com

The test field

For an overview of the test fleet head to the group test: The best downcountry bike of 2022 – 6 models in review

All bikes in test: BMC Fourstroke 01 LT ONE (Click for review) | SCOTT Spark 900 Tuned AXS (Click for review) | SIMPLON Cirex SL 120 (Click for review) | Specialized Epic EVO Expert (Click for review) | Trek Top Fuel 9.9 XX1 AXS | YT IZZO UNCAGED 7 (Click for review)

Did you enjoy this article? If so, we would be stoked if you decide to support us with a monthly contribution. By becoming a supporter of ENDURO, you will help secure a sustainable future for high-quality mountain bike journalism. Click here to learn more.

Words: Peter Walker Photos: Peter Walker, Benjamin Topf