After wrapping up with my Pivot Switchblade long-term test bike at the tailend of last year, I went into the summer holidays on the hunt for a replacement. I was after something that could double-duty as my personal trail bike, while also being suitable for testing various components throughout the year.

Being brand agnostic the initial net was cast pretty wide. However, I had a few non-negotiables that would help narrow things down. I wanted a bike with 140-160mm of travel, preferably with simple cable routing and a threaded BB. I didn’t want any proprietary components either, which meant no funky headsets, integrated cockpits or odd-shaped standards. I also wasn’t keen to spend a fortune, with my preference being for alloy over carbon.

Having enjoyed reviewing the Specialized Stumpjumper 15 and Giant Trance X, the alloy versions of those two bikes were high up on the list. I’ve also been loving the Trek Top Fuel of late, and that encouraged me to throw the longer travel Fuel EX into the mix.

The current Gen 6 platform was launched back in 2022 so it’s not exactly a new bike. I wouldn’t call it outdated though, and it otherwise ticked all of the boxes on my hit list. The pricing has also dropped significantly across the range since the highs of the Covid pandemic, and when Trek decided to put last year’s Fuel EX 8 on special during its Boxing Day sale, that was enough to tip me over the edge.

It’s undoubtedly a whole lotta bike for the money, though riding it in the stock spec wasn’t part of the plan. As soon as I pulled it out of the box I stripped it right down to the bare frame. The next few weeks were then spent building it up with a variety of old test parts as well as brand new ones that I’d be reviewing over the coming months.

It ended up turning into an absolutely ripper bike, and I’m honestly surprised at how stoked I am on it. Before we get to my riding impressions, let’s take a closer look at the specs and some of the highlights from my custom build so far.

A refresher on the Trek Fuel EX

Flanked by the lightweight Top Fuel and the big travel Slash, the Trek Fuel EX is designed to be a versatile All Mountain bike that’s up for a bit of everything.

Built around the long-standing ABP suspension design, the stock bike comes with a 150mm travel fork, 140mm of rear travel and dual 29in wheels. However, the frame is rated for use with a 160mm travel fork and it’s also possible to set it up as a mullet. If you decide to fit a 27.5in rear wheel, you’ll want to flip the Mino Link chip into the High position to lift the BB back up to a reasonable height.

Further adjustability is offered via a leverage rate flip chip in the lower shock mount that lets you switch between 16% (Less) and 21% (More) progression. The latter setting is ideal if you wish to run a coil shock.

The Fuel EX also incorporates an adjustable headset. Neutral cups come fitted as standard, though you can purchase offset cups to slacken or steepen the head angle by a degree. Removal and fitment of the lower cup requires specific tools, so it’s not as user-friendly as the adjustable headset found on Specialized mountain bikes like the Stumpjumper 15.

The Fuel EX otherwise gets all the usual features you’d expect for a modern trail bike. There’s in-frame storage, ISCG 05 chainguide tabs and internal guide tubes for the cables and brake hose. I particularly like the full coverage bolt-on downtube armour, which along with the noise-cancelling chainstay protector, leads to a quiet ride and less concern for high velocity trail projectiles.

The new RockShox Super Deluxe

With the exception of the cheapest model, every Fuel EX is equipped with a Fox Float X shock. I honestly didn’t love the rear suspension on the Fuel EX 9.9 I tested back in 2022. The custom digressive compression tune provided a strong pedalling platform, but it also transferred more feedback than I would have liked.

I planned to send the shock off to Fox to get it re-valved before hitting the dirt, but around the same time I was hearing a lot of positive things about the latest RockShox Super Deluxe. Having had great experience with the previous version I was curious to see what the new shock could bring to the Fuel EX.

Overhauled last year, the Super Deluxe looks identical on the surface. There’s a large rebound clicker at the head of the shock, and the Ultimate version incorporates high and low-speed compression adjusters. There’s also a two-position climb switch and an optional Hydraulic Bottom Out (HBO) circuit that adds position-sensitive damping for the final 20% of the stroke.

Inside is where things get more interesting. Compared to the previous version the new Super Deluxe features a redesigned reservoir assembly, an updated high-flow main piston, and a lighter rebound check plate. Along with increased bushing overlap that aims to reduce friction, the new shock is said to be smoother and more free-flowing. RockShox has also introduced a new bigger Linear XL air can that offers a broader range of volume spacer tuning that allows it to straddle the gap between the existing Linear and Progressive air can options.

What’s cool about all the new updates is that they’re retrofittable to the previous Super Deluxe. That means you wouldn’t necessarily have to buy a whole new shock if you were looking to upgrade.

Shock tuning & setup

After speaking with Trek and RockShox to find out the recommended tune for the Fuel EX, it was suggested that I go with the progressive air can along with the optional HBO. I’d start with no Bottomless Tokens and add any as needed.

The custom tune we went for is C37/R55/X4. This sees a reasonably light compression valve (C37) paired to a linear rebound tune (R55). The X4 refers to the lockout tune, which adds four times the level of compression damping when you flip the lever into the Firm mode.

For those wondering, SRAM Australia can have a brand new shock custom tuned for $220 AUD plus $27.95+ for the necessary shim kit. You could also send in your existing shock, though you’d need to add on the cost of a service. Still, it’s potentially money well spent to get the desired performance from your bike. That will especially be the case for riders who are outside of the typical 60-85kg weight range.

With the correct tune for the bike, the setup has been pleasingly straightforward. After inflating the air spring to hit 30% sag (200psi) and dialling in rebound (9/15 clicks), I positioned both the low and high-speed compression adjusters in their neutral positions. The shock felt fantastic right away, and aside from adding 10psi after the first few rides as the internal seals and bushings have bed in, I’ve not had to touch anything else so far.

RockShox Lyrik Ultimate

To match the Super Deluxe, I’ve got a RockShox Lyrik Ultimate set to 160mm of travel.

I spent a lot of time on this fork last year for a head-to-head battle with the Fox 36, which saw the Lyrik coming out victorious thanks to its superior sensitivity and near-silent Charger 3.1 damper. That made it an easy choice for the Fuel EX, particularly as I was keen to try it out with 160mm up front.

With the longer fork, the head angle has slackened out to 63.5° according to my measurements. That’s with the neutral headset cups and the Mino Link in the Low position. I measured the BB at 334mm off the floor, which is much the same as what Trek claims with the shorter 150mm travel fork. I suspect a small amount of negative travel from the suspension may be responsible for the ‘real world’ BB height being lower than what’s listed in the geometry chart.

The longer fork also slackens out the seat tube angle a touch, but it’s not a big deal since it’s already quite steep to begin with. Indeed, with the saddle at my preferred pedalling height, the seat angle clocks in at around 78.5°, which puts me in a great position over the pedals.

Geometry impacts aside, there’s otherwise not a lot to be said about the Lyrik that I haven’t said before. The latest version is considerably more supple and comfortable than the Charger 3 version before it, while remaining quiet on the trail and intuitive to set up. After using the Trailhead app to determine the recommended pressure (65psi) and rebound setting (12/20 clicks), I set the two compression dials to their neutral positions and haven’t looked back. The Lyrik has just worked, and damn well at that.

SRAM Eagle 90 Transmission

You’ll have already, no doubt, seen the news on the SRAM Eagle 90 and Eagle 70 Transmissions. Following in the footsteps of their AXS electronic siblings, these represent the first cable-actuated drivetrains to be built around a hanger-free Full Mount derailleur.

I’ve been testing the more premium Eagle 90 Transmission, which is effectively the mechanical equivalent of GX AXS. In fact the two groupsets share exactly the same cassette, chain and crank arms. The key difference is the new cable-activated shifter and derailleur, which help to bring down the price by a healthy margin.

After two solid months of riding I continue to be impressed by the quiet and accurate shift performance of the Eagle 90 Transmission. It is incredibly reliable under load and has only gotten smoother over time as all the intermeshing surfaces have settled in.

The shifter ergonomics are excellent, offering a lighter action compared to the punchier Shimano XT and XTR trigger shifters. There’s also a good spread of gears from the 10-52T cassette, and I like that SRAM has fitted a steel chainring with bolt-on bash plates for durability.

It’s not all sunshine and rainbows however, with Eagle 90 being more expensive and heavier than an equivalent Shimano XT drivetrain. I think that’s justified given the advantages the direct-mount derailleur brings to the party, but not everyone else will agree. Check out the full story in our SRAM Eagle 90 Transmission review.

SRAM Motive Brakes

Alongside the Eagle 90 Transmission, I’ve also been testing out a pair of the new SRAM Motive brakes.

Featuring a 4-piston calliper that runs on mineral oil, the Motives replace the outgoing Level and Code. According to SRAM these brakes are designed to be light enough for XC racing and strong enough for aggressive trail riding. Need more power for your enduro bike or e-MTB? You’ll be better off looking towards the bigger Mavens.

Personally, I prefer the smoother lever feel and more linear power delivery of the Motives. And after a couple of months of testing I’ve been impressed with how predictable and consistent they’ve been across a wide variety of trail types.

I will say that it is important to choose the right rotor and pad setup for your needs. The stock Motives come fitted with organic pads, and the Expert kit we received is supplied with lightweight CenterLine X rotors that are ideal for XC applications. Given the Motives were on the winning bikes in both male and female Elite categories at the opening two rounds of the 2025 World Cup XCO and XCC series, it’s no exaggeration to say that they’ve already been proven at the sport’s highest level.

For the Fuel EX, I went with the heavier HS2 rotors in a 180mm diameter and switched the pads for a metallic compound. The thicker rotors help to sharpen up the lever’s dead stroke, which is important since the Motives don’t offer any pad contact adjustment. They also boost power and heat dissipation, and that’s enhanced further with the metal pads.

While not quite as powerful as the Codes they replace, the Motives offer plenty of stopping bite for my needs. They’re also easier to modulate across loose surfaces, particularly if you’re not using super sticky tyres.

That difference is even more pronounced when comparing them with the Mavens, which are a lot grabbier and ramp-up more aggressively as you squeeze the lever harder. That’s ideal for heavier riders on longer travel bikes, but as a lighter rider I’ve often found them to be overkill. The Mavens are also quite sensitive to improper bleeding, and we’ve had several sets suffer from varying degrees of wandering bite point.

In comparison, the Motives have been absolutely rock-solid since their initial setup and bleed. There’s been no change to the lever feel throughout testing, and if anything they’ve only gotten smoother as the seals have bedded in. I’m yet to ride them in really cold and wet conditions so I can’t comment on their performance in that regard, but outside of that I’ve been thoroughly impressed.

For more info on weight, specs and pricing, see our detailed SRAM Motive brake review for the lowdown.

RockShox Reverb AXS dropper post

Topping off the new product releases is the latest RockShox Reverb AXS dropper. Now available with up to 250mm of travel, the new Reverb AXS sees its battery module relocated to the top of the outer tube where it’s tucked out of harm’s way. This does increase the stack height slightly, though I’ve still been able to squeeze in 175mm of travel thanks to the relatively short seat tube on the Fuel EX.

Inside is an air-only spring design that is simpler and easier to service. It also incorporates the ‘ActiveRide’ function that offers a bit of squish whenever the post is lowered below full height. This adds some comfort for technical climbs, but it also creates a sense of lag since the post continues to compress a few millimetres after you’ve released the button on the AXS remote.

You also need a bit more force to compress the post in the first place, which is down to the air spring’s very high pressure (600psi!). I’ve since lowered that to 550psi to free up the action a touch, and a recent firmware update via the SRAM AXS app has also improved the response time of the electronic actuator.

Return speed is plenty fast and I like the audible top-out “thunk” when the saddle hits full extension. We’re also impressed with how solid all three of our Reverb AXS posts have been over the past few months of testing, with zero rotational or lateral movement to speak of.

XC racers will be disappointed that the new Reverb AXS dropper hasn’t gotten any lighter, and indeed it remains one of the heavier options on the market. On the plus side it has gotten a lot cheaper, which is awesome to see. Check out all the details in our RockShox Reverb AXS review.

Any other spec highlights?

The rest of my custom build consists of spare parts I had lying around as well as several components that I’ve reviewed previously. That includes a Race Face Turbine alloy bar, which is one of the few options on the market that’s offered in my preferred width of 760mm. It’s matched with a Turbine R stem, thin-diameter Chester grips and an Ergon SM Pro saddle.

Keeping it all rolling along is a Race Face Turbine alloy wheelset, which has remained true and problem-free after many kilometres. The rims are shod with a pair of Maxxis DH casing tyres, which may seem a bit OTT for a trail bike. However, after several non-repairable pinch-flats of late, I decided I’d just bite the bullet and fit these as they were the only spares I had. They certainly aren’t light or fast-rolling, but the level of damping and grip is just too good for me to give up now. The thick dual-ply casings mean I can run low pressures (19psi front and 21psi rear), and despite not running CushCore I am *desperately searches for wooden surface* yet to get a single puncture or ding the rim.

What do you dig about the Trek Fuel EX?

There’s nothing overly special or different about my Fuel EX. Put simply, this is just a really, really good trail bike.

For a start, Trek has to be commended for offering seven frame sizes. Many brands only produce four sizes, which can lead to significant gaps between sizes, forcing riders to compromise on their preferred reach and stack.

That is not the case with the Fuel EX, and for me the medium size has been absolutely spot-on for my 174cm height. The fit is comfortable and the geometry is nicely balanced even with the bigger 160mm travel fork. Given there’s a negligible weight difference, I’d highly recommend Fuel EX owners consider fitting a longer air spring to the stock fork if they’re chasing greater descending performance.

The suspension itself is a big part of this bike’s performance, and to me it reinforces the importance of spending your cash on a quality fork and shock rather than going for a fancy carbon frame.

In part thanks to the Super Deluxe shock, the rear suspension is outstanding. It is way more supple than the stock Float X, offering more comfort and traction over smaller rubble. Despite this it never feels doughy, with a sufficient amount of damping support that keeps it high in its travel to maintain pedalling stability around the sag point.

On bigger hits, the HBO circuit delivers a beautifully soft catch to the final 20% of the travel. I like that it does this without you having to add Bottomless Tokens, which can sometimes make a shock feel a bit too springy. There is no risk of that here, with the Super Deluxe remaining calm, smooth and quiet. Even with the leverage rate flip chip in the ‘Less’ setting, I’ve not once encountered a harsh bottom-out, while still being able to use all the travel.

Indeed the control this shock brings to the Fuel EX makes it exceptionally capable for a 140mm travel bike. It means it doesn’t feel mismatched with the 160mm travel fork, quite the contrary, it’s as if it was always designed this way.

Front-to-back, the Fuel EX is impressively smooth and active across chunky terrain. Part of its damping qualities can be attributed to the DH-casing tyres as well as the alloy frame, wheels and cockpit. There is zero trace of the harshness that I experienced with the carbon Fuel EX, and for me that compliance makes for a more enjoyable ride with better grip.

What could be improved?

It could certainly be lighter! I put my Fuel EX on the scales in preparation for this review, and it turns out the complete bike weighs just over 16kg without pedals, which is quite heavy.

I wouldn’t have guessed it weighed that much, since it’s actually a pretty lively and efficient bike to ride. The steep seat tube angle, neutral suspension and sticky tyres mean it’s an excellent tech climber too.

The hefty rubber is draggy on the flats though. The stocky frame is another notable contributor to the overall weight, coming in at 4.6kg including the Float X shock. Compare that to the alloy Trance X (3.23kg), the Spectral AL (3.63kg) and the Stumpjumper 15 (4.31kg).

Honestly, I’m not all that fussed. Fitting a pair of lighter tyres would do a lot in terms of rolling speed, but if I want to be covering long distances in a hurry I’d be riding a lighter and shorter travel trail bike like the Top Fuel anyway.

Weight aside, there are a couple of improvements I’d like to see made to the frame.

Currently there’s a blank space underneath the top tube that would be an ideal position for a bolt-on accessory mount. Bottle clearance is also kinda tight, with only just enough room for a 600ml bottle on the Medium frame.

My last minor complaint is related to the internal guide tubes, which are configured to route the rear brake hose into the left side of the head tube. This works well for US and Euro riders who use their right hand to operate the rear brake, but it means us Aussies aren’t able to run the hose around the head tube. While it’s only an aesthetic issue, a bit more flexibility with routing would be nice.

Any changes in the works?

Having got it to this point, there is very little I want to change with my Fuel EX. It does everything I need it to, and I like that the current build is geared towards ride quality and toughness over outright weight.

I’m curious to try it out with a mullet setup, though the reason I haven’t done it yet is because it already rides so bloody well with the dual 29in wheels. It’s terrific on the climbs and descents, traction is plentiful, and I’ve not found the handling to be sluggish at all despite the generous 16kg weight.

The compact 435mm rear centre length no doubt helps to keep things agile through the turns, and the suspension is surprisingly poppy given how plush this bike is. Neither the fork or shock suffer from excessive dive, and there’s a good amount of progression to give your feet a usable platform to push into.

That being said, I have had some occasional bum contact with the rear tyre over jumps and when heading down some really steep descents. A 27.5in rear wheel would provide some valuable clearance in that regard, and it’d surely add a bit more cornering enthusiasm too.

Outside of experimenting with the wheelsize (and maybe a coil shock?), the Fuel EX will carry on as a test platform throughout the year. I’ll be using this bike to review any new parts that arrive at Flow HQ, while racking up the hours on the drivetrain, brakes and dropper post to continue evaluating their long-term performance.

What do you folks think of my Fuel EX? Got any questions or suggestions? Let us know your thoughts here or via our social media channels, as we’re always keen to chat bikes!

 Wil’s custom-built Trek Fuel EX Alloy

• Frame | Alpha Platinum Alloy, ABP Suspension Design, 140mm Travel
• Fork | RockShox Lyrik Ultimate, Charger 3.1 RC2 Damper, 160mm Travel
• Shock | RockShox Super Deluxe Ultimate, RC2T Damper, 185x55mm
• Wheels | Race Face Turbine, Alloy Rims, 30mm Inner Width
• Tyres | Maxxis Assegai DH 3C MaxxGrip 2.5in Front & Minion DHR II DH 3C MaxxTerra 2.4in Rear
• Drivetrain | SRAM Eagle 90 Transmission 1×12 w/32T Crankset & 10-52T Cassette
• Brakes | SRAM Motive Ultimate 4-Piston w/HS2 180mm Rotors & Metallic Pads
• Bar | Race Face Turbine, Alloy, 20mm Rise, 760mm Width
• Stem | Race Face Turbine R, 40mm Length
• Grips | Race Face Chester, 31mm Diameter
• Seatpost | RockShox Reverb AXS, 31.6mm Diameter, 175mm Travel
• Saddle | Ergon SM Pro, S/M Width
• Actual Weight | 16.06kg (Medium, Without Pedals)

ABOUT THE REVIEWER - Wil Barrett

Hometown

Bendigo, Victoria

Height

175cm

Weight65kg