While certain bikes are made for incredibly specific purposes, for most
riders, the right tool for the job is a bike that is capable over the
course of an entire ride, not just one or two segments of it. Trek
wanted to maintain the characteristics that made their do-it-all, 26-inch Fuel
EX one of their most popular models while upping its game with the help of
WHO IS IT MADE FOR?
Trek kind of wanted the Fuel EX 29 to be the Swiss army knife of
trailbikes. It was designed to be light and efficient enough that it could be
pressed into service for a cross-country race while retaining enough all-mountain DNA to tackle trails that would usually be reserved for much
more specific bikes.
WHAT IS IT MADE FROM?
The Fuel EX 9.8 29 uses a carbon front triangle, and the rear triangle is
composed of carbon fiber seatstays and aluminum chainstays. In case you
are planning to push the Fuel EX into really rough terrain, it comes with an
ISCG 05 mount for additional chain management.
The rear suspension is Trek’s Active Braking Pivot (ABP) with Full
Floater technology (the shock’s bottom mount bolts to the chainstay, not the
Always a company to sweat the details, Trek’s finish work is top-notch.
The 9.8’s translucent Red Smoke color is stunning in the sunlight, as it
shows off the underlying carbon layers. To help keep it looking clean, Trek
added molded, external downtube and chainstay guards. Cables for the
derailleurs are routed internally through the frame to cut down on clutter,
while the exposed hydraulic lines are routed cleanly along the top of the
WHICH COMPONENTS STAND OUT?
It is fitting that a bike designed for the do-it-all rider be spec’ed with
Shimano’s workhorse XT components. The 2x10 drivetrain with the
Shadow Plus rear derailleur is an ideal trailbike spec that makes finding the
right gear simple and minimizes chain slap.
The internally routed RockShox Reverb Stealth dropper post is not only
one of the most dependable designs available, it also blends in seamlessly on
the Fuel EX 29.
The shock uses Trek’s Dual Rate Control Valve (DRCV)
technology that manually opens an additional air chamber as
the shock moves deeper into its travel. This eliminates the
hammocking effect experienced with traditional large-volume
air shocks. Fox makes the shock for Trek.
HOW DOES IT PERFORM?
As for the cockpit, the Fuel EX is the epitome of a balanced trailbike. The rider’s weight feels very centered, and the top tube length splits the difference between
the aggressive, forward-leaning position of a cross-country
bike and the more upright position of a longer-travel, all-mountain bike. The suspension was easy to dial in, and we
settled on 30 percent sag for both the fork and shock.
With such a versatile platform, Trek’s ABP suspension is asked to handle a wide variety of circumstances.
To get the most out of the rear suspension, Trek’s in-house
engineers tuned the Fox Float CTD themselves, and it
shows. The three-position, adjustable damper helps the rider
dial in the right feel for the ever-changing trail.
Each of the three settings made a noticeable difference, ranging from almost completely locked out in the Climb setting to a
quite active feel in the Descend setting. On the trail, however,
we found ourselves favoring the Trail setting, thanks to its
balanced and versatile feel. In the Trail setting, hard pedaling
efforts in or even out of the saddle felt efficient enough that we
didn’t worry about changing to Climb mode in most cases.
The Fuel EX’s moderate weight and efficient
pedaling platform make it a solid-climbing bike. As the technicality of a climb increased, so did our admiration for the
Fuel’s ability to stay hooked up and power through tricky
sections. Only when we rode it back to back with a dedicated, cross-country bike on faster climbs did we find ourselves
feeling a bit bogged down.
The shock’s Climb setting will certainly appease riders
looking for an ultra-efficient feel, but we preferred the slight
give at the top of the stroke of the Trail setting, which takes
the edge off of rough climbs and helps the rear wheel maintain traction.
The Fuel EX 29 uses G2 geometry originally
developed by Fisher. This geometry takes into account the
offset of the fork in comparison to the wheel and adjusts
accordingly for the bigger size, pushing the fork offset to a
greater 51 millimeters.
Thanks to the dialed geometry, the Fuel handles sweeping corners with all the benefits of the larger contact patch
and greater stability of 29-inch wheels while still being very
nimble around slow, tight switchbacks. This was a handling
issue that troubled Gary Fisher’s early 29er designs.
We did, however, notice a bit of lateral flex in the front
end when pushing the limits in hard corners, through G-outs
or in corners with abrupt berms to lay the bike into. While
it didn’t happen all the time, this was a
reminder that the Fuel EX’s light weight comes at the price
of stiffness when the bike is pushed hard.
Drop the saddle and the bike takes on
another personality. Blitzing through rock sections is much
less worrisome than you’d expect with such a lightweight rig.
While the rear end isn’t on the short side of the spectrum,
the bike is still quite playful and likes to pop off jumps and
manual through rollers.
Trek emphasized the strengths of the rocker-link ABP
suspension layout, and their frame and suspension engineers
worked together to design a rear shock around what they
wanted from the bike as a whole. The result is rear suspension that is predictable, lively and very forgiving. The DRCV
technology helps give the shock a plush but controlled feel
that will have you thinking there are more than 4.7 inches of
travel back there when diving into the stroke.
One of ABP’s biggest strengths has always been
isolating braking forces from suspension activity, and the
Fuel EX 29 definitely benefits. Pairing this solid design with
the stopping power of Shimano XT brakes results in a winning combination.
TRICKS, UPGRADES OR TIPS?
The Bontrager XR-3 tires that come spec’ed on the Fuel
are a solid option, but they are also a bit burly and heavy if trails don’t demand such a tire. For comparison’s sake, we
traded the tires for a slightly narrower, lighter option and
found that the bike instantly felt closer to the cross-country
end of the spectrum and really woke up on the climbs. This
helped to prove how adaptable the bike is with a quick
We were surprised that Trek skipped the 27.5-wheel
option and went straight to the big hoops on their Fuel EX.
After our time on the bike, however, we can’t say it was a
bad decision. The bike handles great. It doesn’t feel big, and
the standover height is fine.
The 26-inch Fuel EX has long been one of Trek’s most
popular mountain bikes, and the Fuel EX 29 is ready to
carry the torch forward. The Fuel EX continues to be a
versatile trailbike that does much more than simply handle
a variety of trails. For most trail riders, the Fuel EX 29 is a
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