Trek's full-sus XC platform offers more than just race-winning performance.

Product Overview

Overall rating:

Score 8

Trek Top Fuel 9


  • Rewarding ride provided by the Re:aktiv suspension.
  • SRAM X1 groupset performed flawlessly.


  • Handling is marred by the miniscule bar width.
  • Tyres are inappropriate for most British conditions.


Trek Top Fuel 9 (2017) review


Price as reviewed:


The same DNA flows through the veins of the 100mm travel Trek Top Fuel 9 as that found in their longer travel Slash and Fuel EX ranges.

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Trek has an effective formula when it comes to making a really rewarding full suspension frame. It features Trek’s ABP (Active Braking Pivot), enabling the suspension to remain active whilst under braking, and also the Mino Link, that allows the rider to vary the geometry by simply flipping two small inserts at the top of the seatstays.

Boost spacing is present both front and rear to aid stiffness for the larger wheel size. The frame also has ports to allow a dropper post to be fitted, showing that Trek has one eye on how the Top Fuel might be used by some riders.

Trek Top Fuel 9

Trek Top Fuel

The Top Fuel 9 in its natural environment


The Fox RE:akitv shock is a unique recipe for Trek that aims to reduce rider-related suspension movement. Using a regressive damping process, it limits movement through pedalling but provides smooth and active travel when confronted by trail obstacles. The version fitted to the Top Fuel 9 has a remote activated lockout to keep hands firmly on the handlebars.

Trek Top Fuel

Trunnion bearing mounts help the Fox RE:aktiv shock respond well to small bumps. The remote lockout is a welcome addition for riders that like to get out of the saddle

The 100mm Float 32 Performance GRIP Step Cast suspension fork is the perfect foil to the RE:akitv shock. The GRIP damper is, on paper, a lower spec than the higher end FIT4. However it uses a similar sealed cartridge to the FIT4, just with a more basic construction.

Trek has fitted both shock and fork with a handlebar-mounted remote to control lockout. In comparison to bikes with a more stable pedalling platform, the lockout is certainly required on the Top Fuel.

Trek Top Fuel

Fox 32 Step Cast fork features remote lockout for the GRIP damper


The Top Fuel has a full sprinkling of SRAM and Bontrager parts. SRAM provides its X1 11-speed groupset, Trek has specced the Top Fuel with a more racy 32-tooth front with 11-42 cassette.

SRAM Level TLM brakes have the more XC/trail oriented single piston design but still provide solid stopping with the 160mm rotors provided.

Trek’s parts company Bontrager is present and correct with the very comfortable Montrose saddle sitting atop a straight aluminium seatpost. It also supplies the super narrow Race Lite handlebar, long Pro stem and thin lock-on grips.

Trek Top Fuel

SRAM Level TLM brakes provide ample stopping power


Swing a leg over the Top Fuel and the first thing you notice is the suspension is keen to get working. Compared to other, firmer platforms such as those found on Canyon’s Lux or the KTM Scarp, the Top Fuel behaves more like an active trail bike.

It’s a seriously rapid bike around trail centres, and it responds well to minor trail imperfections, such as roots and small rocks, allowing you to keep the power on rather than having to ease back.

The fork is equally as plush, yielding the first two thirds of its travel very easily. Fortunately it does get more progressive towards the end of the stroke to cope with bigger hits without harsh bottoming. This enthusiastic use of the travel means if you like to ride aggressively, sprinting and climbing out of the saddle, then the combined lockout is a feature you will cherish.

Trek Top Fuel 9

The all-important lockout.

Performance limiters

The Trek Top Fuel sticks to geometry more suited to fast handling and climbing prowess, with a steep head angle and relatively steep seat angle (even with the Mino Link set to the low position). This geometry plus the choice of componentry act as fun limiters when the trail points down. The combination of in-line seatpost and long stem pitch rider weight too far forward on steeper tracks.

The narrow bar also hinders the all-round abilities and took us straight back to racing ten years ago when sub 700mm bars were the norm. Your knuckles might thank you while riding super twisty race circuits in the trees, but the enhanced twitchiness a narrow bar brings can turn round and bite you when fatigue sets in. Changing to a 720mm width bar immediately improved the behaviour of the bike, making it much more pleasurable to ride.

Bontrager’s XR1 tyre with its low profile tread enabled the Top Fuel to be both blisteringly fast in a straight line whilst behaving like Bambi on ice during cornering on anything other than dry and dusty conditions.


The Trek Top Fuel 9 manages to tread a fine line between a taut and lithe XC race machine and a bike that most riders would be happy to use for general trail duty. There is no doubting its race worthiness but a few component choices need to be addressed for the Top Fuel to really be at the top of the XC wishlist.


Frame:Alpha Platinum aluminium 100mm
Shock:Fox Performance Float, RE:aktiv XC
Forks:Fox Performance 32 Float, Step Cast, GRIP 100mm
Wheels:Bontrager Mustang Pro BOOST/ Bontrager XR1 Team Issue 29x2.20" (27.5" on 15.5" frame size)
Drivetrain:SRAM X1, 32t, 11-40 cassette
Brakes:SRA Level TLM 160mm/160mm
Components:Bontrager Race Lite handlebar 690mm, Bontrager Pro stem 90mm, Bontrager Rhythm Elite seatpost, Bontrager Montrose Elite saddle
Sizes:15.5", 17.5", 18.5", 19.5", 21.5"
Weight:11.94kg/26.32lbs (19.5")
Head Angle:70.3°
Seat Angle:69.1° (effective 74.6°)
BB Height:330mm
Front centre:704mm
Down tube:701mm
Top tube:602mm