Trek Fuel EX 9 29 review

The Fuel you need to set the trails alight?

Our rating 
4.0 out of 5 star rating 4.0
GBP £3,200.00 RRP | AUD $5,199.00 | USD $4,000.00

Our review

Not the quickest climber, but clever suspension and geometry provide a fun, fast and capable ride
Buy if, You're not competing for uphill KOMs, but want a relatively rapid and comfy all-day mile-muncher that can be ridden really hard too
Pros: Great geometry and kit encourage aggressive riding; comfortable and fast on rolling terrain
Cons: Seat angle could be steeper for climbing; not the lightest
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Trek’s trail 29er sports 130mm travel at each end. There’s a carbon version for the same price, but I opted for the alloy bike due to the lure of posher parts.


Trek’s ‘ABP’ (Active Braking Pivot) suspension design puts the rearmost pivot concentric with the wheel axle, rather than on the chainstay. As with Horst Link bikes, such as the Specialized Camber Comp Carbon 29, the rear brake caliper is mounted on the seatstay, so braking forces don’t interfere with the suspension as much as on a traditional single-pivot design.

The straight down tube is claimed to improve stiffness. Trek’s ‘Knock Block’ limits the steering lock to stop the fork crown hitting it
Steve Behr / Immediate Media

The frame has a straight down tube, which is claimed to boost stiffness but would normally be in the path of the front wheel. Trek’s ‘Knock Block’ system limits how far the bar can turn, to stop the fork crown contacting the frame. This reduced steering lock isn’t usually noticeable when riding — just don’t try any barspins!

Included in the solid spec is a sensible 760x65mm cockpit, wide Bontrager wheels, SRAM X1 gearing and Guide RS brakes. The Fox shock uses Trek’s Formula One-inspired RE:aktiv damping tune, which is claimed to improve pedalling.

Trek Fuel EX 9 29 ride impression

The Fuel EX needs that clever damping tech. Pedalling stood up with the shock in ‘open’ mode results in a fair amount of bob.

Add a tough, wide wheelset and stiff frame, and the Fuel EX rewards you for chucking it down rocky chutes and stuffing it into corners

Flipping to ‘medium’ cuts down on this a fair bit, and large bumps are absorbed almost as if the shock had been left fully open. This is because of the RE:aktiv tune, which offers quite firm low-speed compression damping, particularly in the ‘medium’ and ‘firm’ modes, but allows the valves to pop open under harder impacts.

While this is handy for pedally descents and technical climbs, it’s not quite the best of both worlds. When sprinting, the firmest mode still permits a little bob, while in the ‘medium’ setting, the shock feels slightly insensitive. Left ‘open’, the suspension performs pretty well over rough ground and absorbs big hits nicely.

The fork’s GRIP damper is less responsive to trail chatter than more expensive units found on bikes such as the Norco Optic C9.2 too, so when battering over really bumpy ground, the 130mm Trek wasn’t quite as smooth as I’d hoped.

Although the cockpit is relatively well-proportioned, I’d fit a shorter stem to get the most out of the long reach, as the Fuel EX felt a touch stretched-out on steep descents. The tyres lack bite in corners too.

Trek’s RE:aktiv damping tune resists pedalling forces but opens up to absorb big bumps
Steve Behr / Immediate Media

SRAM’s Guide RS brakes performed well, helping to push the Trek’s trail chaos confidence.

I used the ‘low’ geometry setting for most of my testing, which gave a confidence-inspiring ride. With a 67-degree head angle and fairly long front centre, the Trek felt like a capable and stable descender.

Add a tough, wide wheelset and stiff frame, and the Fuel EX rewards you for chucking it down rocky chutes and stuffing it into corners.

At 13.9kg it’s on the heavy side, and it’s got the stiff gearing too, making steep, sustained climbs a bit of a chore. More importantly, the ‘low’ setting results in a 74.5-degree effective seat angle. Although this is steeper than bikes such as the Canyon Neuron AL, I found it a little too laidback for attacking technical climbs. Switching to the ‘high’ setting helps, but this also raises the BB and steepens the head angle, losing the Fuel EX its descending edge.


Although it’s not the fastest climber, it’s no slouch. The fast-rolling, high-volume tyres carry speed exceptionally well. With the shock in the firmer settings, it responds well to pumping and pedalling efforts, too. It bowls along flowing trails effortlessly and really comes alive when pointed downhill.

Product Specifications


Name Fuel EX 9 29
Brand Trek

Available Sizes 15.5in 17.5in 18.5in 19.5in 21.5in 23in
Rear Tyre Bontrager XR3 Expert 29x2.4in
Wheelbase (in) 48.03
Top Tube (in) 25.2
Seat Tube (in) 20.47
Chainstays (in) 17.13
Bottom Bracket Height (in) 13.19
Spoke Type DT Swiss, 28
Weight (kg) 13.9
Stem Bontrager Line Knock Block, 65mm
Shifters SRAM X1 (1x11)
Seatpost Bontrager Drop Line 125mm dropper
Seat Angle 74.5
Saddle Bontrager Evoke 2
Rims Bontrager Line Comp 30
Rear Wheel Weight 2700
Rear Shock Fox Float DPS EVOL Performance RE:aktiv
Bottom Bracket SRAM
Front Hub Bontrager Line Comp Boost
Brakes SRAM Guide RS, 180/180mm
Cassette SRAM XG-1150, 10-42t
Chain SRAM PC-1110
Cranks SRAM X1 1200, 32t
Fork Fox 34 Float Performance, 130mm (5.1in) travel
Frame Material 'Alpha Platinum' aluminium
Front Tyre Bontrager XR3 Expert 29x2.4in
Rear Hub Bontrager Line Comp Boost
Front Wheel Weight 2130
Grips/Tape Bontrager
Handlebar Bontrager Line, 750mm
Head Angle 67
Headset Type Trek Knock Block, integrated
Rear Derailleur SRAM X1
Frame size tested 21.5in