Trek Fuel MX – a Small Rider’s Review

The 2026 Trek Fuel is a frame that can be built to be your perfect trail bike, however it may look. Sharing the same frame, the adaptable trail system gives riders the option to build from three baseline configurations (EX, MX and LX). From there, there are two lower shock mounts (two physically different mounts, High/27.5 or Low/29) with a progressive flip chip on the lower mount.

The options are quite overwhelming, understandably, and most riders who buy a bike like this won’t have all the necessary additional parts (spare wheel, links, shock and fork) to play around with all the possible combinations. Trek says its rider research found most size S riders prefer a 27.5″ rear wheel for a more proportional fit and more clearance between the rear wheel and the body on jumps and descents. That’s why the size S EX ships mixed-wheel with the MX link. Other bikes let you fit a smaller rear wheel or a different shock, but without frame hardware built to match, so geometry or suspension feel takes the hit. The Fuel’s interchangeable rocker links and shock mounts are what let it adapt instead of compromising.

My objective with this review was to test those options that fit my ideal travel range on the mullet version. I’m 5’2″ and ride the North Shore as my main terrain, so when I’m looking for a new bike, I want something stable enough for chunky terrain but still playful and easy to maneuver. My ideal travel, if I had one trail bike, is 160-170mm in the front and 140-165mm in the rear, and that is exactly what I tested.

I only tested mixed-wheel setups (29″ front, 27.5″ rear) with the high/27.5 lower shock mount, since I didn’t want to bring a 29″ rear wheel into the mix. Trek’s own configuration chart breaks this down: with the MX rocker link, the high 27.5 lower shock mount and ideal suspension range, only a handful of real options exist. That left me with three configurations to test, plus one combination Trek doesn’t officially list at all. For reference, Trek shared a spreadsheet with 26 different combinations for the Fuel, with 9 configurations noted as “not recommended” due to bottom bracket heights that would be too low or too high.

The bike

I received the Fuel MX 9.8 XT Di2 in a size small, in the stock configuration in Gloss Chameleon Green / Matte Black. It’s the 2026 model: OCLV carbon frame, Fox Factory 36 with 160mm of travel, Fox Float X air shock (205×60), Shimano XT Di2 with a 10-51 cassette, XT four-piston brakes, and Maxxis Assegai and Minion DHR II tires (EXO+ casing). Trek lists this build at 32.88 lb (14.91 kg) and it’s priced at 9,000 CAD / 6,500 USD.

Already this bike was a 4/5 for being able to fit a full-sized water bottle. The water bottle problem for small bikes is a real, unfortunate thing and something that I take into consideration. The paint job is beautiful, I like the gloss and matte combination, and the green sparkles and camouflages itself well in the forest. The bike becomes easier to spot once I put the orange fork on, which I think matches well with the green. There’s great frame protection under the downtube and on the chainstay and the straight seat tube leaves more room to add a larger dropper. The small comes with a 150mm, although I feel like I could use a 170mm. I believe all other frame sizes can fit a 200mm dropper.

The downtube storage has enough room, but less than other frames I’ve seen. It comes with two frame bags, but I didn’t manage to fit any of my tools inside (the OneUp pump and my tire plug tool couldn’t fit through the opening). In theory, one of the bags will fit a flat kit but it does have to be quite compact and likely a CO2. In practice, I used one of the frame storage bags only to carry snacks, and then I stuffed in a light jacket when needed. The lock on the storage is a real highlight, though: it feels tight and strong enough not to loosen over time, more secure than other systems I’ve seen.

With the MX link, the high mount, and mixed wheels, Trek’s configuration chart only gives you three fork-travel options once I ruled out a 150mm fork. I rode the first three options, plus a fourth combination that isn’t in the chart at all:

Stock MX

Out of the box, I took the bike straight to ride some lower angle and less jarring trails in places like the Sunshine Coast and Kamloops. This type of terrain was where I felt this setup performed best. It was fast, super playful and capable, and still felt planted and stable. I also took it to the Grouse Bike park for the first time, which I wouldn’t consider a particularly challenging bike park, and it was plenty fun and capable on jumps and blue tech. I did not feel under biked there.

I found the limits of this configuration as I got more comfortable riding it on the Shore. The terrain here doesn’t forgive much: it’s harsh, and once the trails dry out for summer, everything speeds up and gets looser underneath you. I was on the brakes far more than I had been on the lower-angle trails, and that is exactly where this setup started to show its limits for me.

Up front, the 36 flexed under braking on steep, technical sections. I could feel the fork twisting rather than just compressing and the front end would wander slightly off the line I’d picked. In the back, the air shock was chattery over the same terrain, skipping and deflecting over rapid small hits instead of settling in and tracking. Together, the bike felt noodly at both ends at the moments I needed it to feel precise.

For someone who will be riding this bike on terrain that is more forgiving and likes a playful, fast feel, the stock MX build is capable as it is.

Stock MX 65 stroke configuration

Luckily, the Fuel MX has options to address my needs. Moving to the second row in the table, I put on the orange Fox 38 performance and swapped the air shock for a Fox DHX2 coil (205×65, 250 spring). This adds travel to both the front and rear, slackens the head angle by half a degree and increases the BB height by 5mm. It also increases the progression rate in both flip chip settings.

This configuration made a load of difference in how the bike felt. I immediately felt like I could attack steep corners with the confidence that the bike would stay pointed. The 63.5 degree head angle is my sweet spot and the coil had the bike feeling more planted and stable, with less chatter. Moving to this configuration can increase the progression up to 5% depending on the flip chip setting. With the coil, I ran the more progressive setting to balance out the coil’s linear spring curve. With the air shock, I ran the less progressive setting which gave more support off the top. The only downside with the coil is that it was noticeably less fun and easy to get in the air. It would have been interesting to test this configuration with an air shock instead; I bet it’s great fun.

Across these first two setups, the bike climbs very well. I never once felt the need to lock out either shock, the bike stays reactive and keeps traction whilepedaling through technical ups. My position changed slightly with the bigger fork putting more weight towards the back but it wasn’t enough to notice a big change in pedal efficiency.

LX Rocker Mount

Moving to the third configuration, the only thing that changed was the LX rocker link. This configuration is the only option that allows a mixed wheel set up with the LX link. In this set up, there’s a negligible 1mm less of rear travel, it drops the bottom bracket by a full centimeter from the previous option and slackens the head angle to just under 62.9° (which is the slackest of all options available for the Fuel). This option was intriguing, especially on a coil, as it gives even more progressive rates for both flip chip settings and adds stability by dropping the BB height.

Despite the very slack head angle, this configuration was surprisingly capable, and I felt the increased support through the travel and the lower BB height keep me even more planted. The lower BB was not an issue for clearance, but I did notice that it felt harder to pedal the bike. The slacker head angle made steering and holding a line harder, especially seated on a climb.

This LX-link configuration is a good option for someone who wants to keep the MX wheels but wants more flexibility in their progression, especially with a coil shock. You’ll just settle for a noticeably slacker feel and a bit more plow.

MX rocker, 170mm fork / 150mm air shock setting

The last configuration that I ended up trying as I waited for the coil to arrive was the 170mm fork with the stock 205×60 air shock with 150mm of rear travel. In the table, I take a guess as to what the progression rates, BB height and head angle were as this setting was not listed in Trek’s suggested configurations. I had the support of a bigger fork in the front with the playful air shock in the back, but the rear stayed chattery and less planted and I tended to sit further into the travel. Despite that front-rear imbalance, it was still a very capable setting, keeping that lively air shock feel throughout.

Shimano Di2 derailleur

Yes, a whole section dedicated to this component. This is my first time on the Di2 derailleur, and the biggest takeaway is how loud it is. It took me multiple rides to realize nothing was loose on the bike, it’s extremely loud when it snaps back into place after an impact. Like, shockingly loud. I’ve polled the whole community and everyone agrees this derailleur is in its own league of noise pollution. It was becoming hard to figure out if I was bottoming out the suspension or not because it would snap back into place, make a ridiculous noise, and reverberate through the whole bike.

Where it fits

For a rider wanting to dial in geometry without compromising on suspension feel, this flexibility is genuinely impressive and I appreciate the multiple mullet options for small riders. I also think resell value on this bike will be strong, since it won’t be locked into whatever configuration the next owner inherits. Understandable, I doubt the average buyer will tinker with it like this. Getting from stock to any of these setups means buying real parts: a rocker link (CAD $130), a lower shock mount ($26 each), sometimes a longer fork, sometimes a coil shock, sometimes a wheel. All of which are hundreds of dollars.

If you know you want the second setup (MX link, High/27.5 mount, 170mm fork, 162mm coil shock), you’re better off buying the stock LX and converting it than buying the stock MX and upgrading suspension. Stock LX already ships with the 170mm fork and the 205×65 coil shock. From there you’d need the MX rocker link ($130), the High/27.5 lower shock mount ($26), and a 27.5″ rear wheel and tire. Starting from stock MX instead means buying a new fork and a coil shock outright, which will cost you more than that regardless of wheel size. For a rider looking to stay on the lower end of the travel range, both the stock EX and MX options are a really great starting point.

My favourite setup ended up being the 65mm-stroke MX build: 170mm fork, 65mm stroke shock, MX link. It kept the agility that draws me to mixed wheels in the first place while giving me the support I needed for the trails I ride daily without compromising on climbing capability. If you’re set on the Fuel, choosing your desired travel first, then wheel size will point you to the best stock option to launch from.

Trek Fuel