Words Liam Friary
Images Cameron Mackenzie
RRP$15,499
Distributor Trek New Zealand
The lines are somewhat blurred between an XC long-travel bike and a lightweight trail bike but, regardless of categorisation, the bike is designed to be super-adjustable with a redesigned frame and a 4-position Mino Link. There’s also a ton more you can customise, like wheel size, geometry, and suspension travel, making it super appealing for everyday trail riding, or even XC racing duties.
Trek has opted for refinement rather than revision – a trend the industry is increasingly embracing. Generally, bikes are in a good place regarding geometry numbers, so there’s no need to reinvent the wheel – at least for now. While the new Top Fuel looks similar to the previous generation, it has gone on a slight diet with about a 100g savings in the carbon frame, and employing slimmed-down tubes across the entire frame. The new 4-position flip chip, used for adjusting the bike’s geometry or the amount of shock progression, is located at the lower shock mount. This flip chip offers High/Low geometry settings that modify the angles by 0.5° and change the BB height by 6mm. Additionally, you can move the suspension leverage rate forward and backward with the flip chip. The forward position offers 14% progression, while the rear position offers 19%, providing more ramp-up at the end of stroke. I rode mainly with the rear, more progressive position and found it better suited to my riding style and the terrain where testing was done.
I appreciate the ability to change out the rear and front travel if desired. The rear shock is built around a 185x50mm shock, but you can increase the stroke to 55mm and boost travel to 130mm. The frame is rated for a 120-140mm travel fork, which allows for different setup options, such as an XC whippet with 120/120mm travel or a rowdier trail bike with 140/130mm travel. I’m inclined to build the latter so, hopefully, I’ll have more on that sometime soon. If you wanted to have a mullet setup with a 27.5” rear wheel, that’s also possible with this new platform.
Returning to small refinements, the new Top Fuel is slightly more progressive than the previous generation and has a tad more anti-squat. Rear travel is kept at 120mm and comes with a 130mm travel fork up front. 29” wheels are standard on all frames except the small, which is built around 27.5” wheels. The internal storage has also been updated with larger openings and better weatherproof sealing, and cables have been kept out of the way to minimise snagging. Trek has won the applause of shop mechanics by keeping cables out of the headset and eliminating the Knock Block headset. A tried-and-true threaded BB is used, as well as bolt-on downtube armour and a rubber chainstay protector.
While there are slight changes to geometry, the 65.5° head angle remains consistent across all sizes. The effective seat tube angle ranges from 75.2-76.9°; Trek lists this angle based on a specific saddle height for each size. Another update is the size-specific rear centre lengths, which vary from 435mm (smaller frames) to 445mm (X-Large frames).
I had the pleasure of riding the new Top Fuel in Durango, Colorado, USA. Having more than a week based in Durango meant I could get very familiar with the bike, logging over fifteen hours of ride time. There’s plenty of pedalling needed in Durango, and often you’re either riding long climbs, flats and descents that have pedal sections. I thought this bike was well suited to the terrain. The first thing that struck me was the pedalling efficiency and overall zippiness of the bike. I rode twice a day locally and had two high-country long ride missions as well. On all occasions, from road to gravel to trail, I didn’t feel the need to hit the lockout lever, as it pedalled great with it wide open. The bike feels swift and light and climbs exceptionally well.
The Top Fuel’s adaptability is the new four- position Mino Link at the lower shock mount. Effectively, this set of flip chips allows riders to choose between permutations of high and low geometry, and more linear or more progressive suspension curves. Initially, for the first few days of riding around the mountain bike parks of Durango, I had the Top Fuel’s flip chip in its default ‘low, less progressive’ setting. As we headed for longer high-country rides, a simple flip of the chip meant I could steepen the head tube angle by .4° and raise the BB by 6mm. I found this setting was ideal for ramping-up. It offered adequate dampening and felt comfortable even after several hours in the saddle. The more progressive setting reigned supreme across rowdier terrain on the longer descents in Colorado’s high- country. The bike moves very swiftly, especially over long rides. I’m a big fan of the flip chip!
While the RockShox Pike fork nods to more trail-oriented riding, there’s something about the overall frame that makes it more compliant than the white paper stats indicate. This compliance was evident when we ventured into the backcountry, which made for lengthy and rowdy descents. These rides were often long – around three hours or more – so having a compliant frame was welcomed. These rowdy sections are when the bike feels burlier than presumed. Again, on descents, the Top Fuel chassis is bloody solid; with the bike’s light weight, this is a little surprising. But, when you throw that together with the progressive rear kinematics, it’s confidence inspiring. Bear in mind, when things get really real – rough and steep and you need to pick your line – apply a bit more effort to stay cantered and weight both axles. That said, the newly designed compliance of the frame and separate linkages means smoother, grippy moments when it matters most.
On the shorter, punchier rides in and around Durango’s extensive trail network, the bike was super smooth and sprightly. Heck, simply making your way to the trailhead, the Top Fuel is just as sharp – sprinting forward eagerly as soon as you put the slightest pressure on the pedals. Uphill, it’s just as powerful and lively. From more XC-oriented loops to bike park-style jumps and berms to rock slabs, with sketchy rocky descents, the rear end stays active, even under brake load. I think the key component is the four-bar suspension platform over a single- pivot flex-stay, which offers superior grip both uphill and downhill. There’s suitable snappiness, and the bike generates speed very well.
Standing is fine but, for seated climbing, the Top Fuel is a beast. It soaks up big roots and rocks without losing traction or bouncing you offline. On rockier technical climbs I would normally not make it, but it would clear them. Although it’s not technically an XC race focussed rig, the Top Fuel is a super capable climber. And, with it being so well balanced, you can pick your way through more technical sections without having to carry a lot of momentum in. Cornering aboard this rig is bloody fun too. Leaning into flatter corners and railing berms is awesome. The balanced ride pays off here – keeping an ideal amount of weight on both wheels which keeps it easy to judge traction.
The Bontrager Line Pro 30 OCLV Mountain Carbon wheels do a great job. They’re sprightly and engage swiftly. These wheels are laced with Bontrager Gunnison up front and Bontrager Montrose out back – these tyres keep in fitting with the bike’s lightweight theme. I found them super supple and quite zippy but, on gnarlier rockier sections, I had to choose my line. Whilst they didn’t give me any grief on rockier descents, choosing the best line was imperative, as I was a tad worried about snagging them. I can understand the thinking behind choosing to spec these tyres, but if the bike remained with me, I’d prefer something a little beefier – even with the weight penalty. In saying that, they did hook up well – and impressed me on faster rolling sections. I suppose it really depends on your application for this trail bike, as it’s up for wide interpretation.
Keeping with the parts and component’s theme – the RSL MTB Handlebar and Stem comes equipped on the Top Fuel. On trail, I found the RSL handlebar/stem combo to be quite comfortable. It wasn’t overly stiff nor super compliant; it sat in the middle somewhere, which was kind of great as meant I could focus on the ride. I quite liked the RSL bar’s good feel, with enough damping to keep your hands from taking too much abuse. It provided reasonable comfort and was plenty stiff when accelerating out-of-the-saddle. The sweep and rise were dialled for me, as I usually run a slightly forward roll on my bar, but it won’t suit everyone. Although I do love the super tidy aesthetics and feel of the Bontrager RSL integrated bar and stem, I do think perhaps a more traditional bar/stem combo would possibly suit more riders. As the rest of the bike has quite a lot of adjustability, it would be good to have the same within the cockpit. Such as swap a shorter stem for gravity focused days and a longer one for long ride days or racing.
SRAM’s XO Transmission does a flawless job of shifting. I did break the chain, however, and luckily we had another chain-link with us in the backcountry. But that can happen at any time, to any groupset. I have XO Transmission on my personal bike and it’s super robust, shifts flawlessly and you never have to faff with it! I think if you’re spending your hard-earned cash on a new bike, then having Transmission is definitely worth your consideration. SRAM Level Silver four- piston brakes, with 180mm HS2 rotors front and rear are on stopping duties. I did find these brakes fairly good for some of the riding, mainly around the mountain bike parks of Durango with shorter descents. However, on longer descents in the backcountry they weren’t powerful enough. Keep in mind, that was mainly on super long runs with chunder sections throughout. I have been riding SRAM Maven’s on my personal bike, so am a bit partial to a heavy hitting brake. Again, if the bike was mine, I would upgrade to a bigger front rotor and possibly swap these brakes to SRAM Codes.
This bike is bloody fun! Hands down one of the best bikes I’ve ridden this year. It’s sprightly but super capable. The balanced ride inspires a ton of confidence. It pedals everywhere super efficiently – dances uphill, generates speed across flats and shreds going down. Its more bike than you think and makes a strong case for having a shorter travel bike! Of course, there’s a few nit bits that could be addressed as I’ve mentioned but, overall, the new Top Fuel is all class. I’m very keen to build this bike as a burlier 140/130mm trail bike, so hopefully we can make that happen soon.
