Trek Top Fuel
Words by Henry Quinney, photography by Tom Richards
Step in the new Top Fuel. Once a purebred XC race bike, it’s now morphed into a longer travel contender in the downcountry and trail category. But how does it stack up, and has it lost any of its bite since leaving the race scene behind?
• Travel: 120mm rear / 120mm front
• Wheel size: 29″ (except XS)
• Head angle: 66° (low)
• Seat tube angle: 76° (low)
• Size tested: large
• Reach: 480 mm
• Chainstay length: 435 mm
• Sizes: XS, S, M, M/L, L , XL, XXL
• Weight: 26lb 3 oz (11.9 kg)
• Price: $10,500 USD (as shown)
To look at the geometry chart, it becomes clear that the Top Fuel is a fascinating prospect. Its slack head angle and long reach seem to have been plucked from bikes with far burlier intentions. However, it’s not quite as radical as something like the Rocky Mountain Element, nor is it as tall at the front as something like the Niner Jet RDO, both of which we also tested.
The Top Fuel has one or two geometry dimensions that set it apart from the others, most notably it’s a lot lower on the front than some of the other bikes. Its stack figure is around 25mm lower than the Niner, for instance, and that’s not even factoring the high-rise bars that come on that bike. The dimension of stack can not only have a large effect on the handling of the bike, but also what terrain the bike will thrive in.
It’s also the longest bike on the test. In its high setting, it has a reach of 484mm. Yet it’s not the steepest in the seat tube angle. It’s certainly very adequate, but the long reach, combined with a 76-degree seat tube does give it a moderately long effective top tube length of 630mm. Although this is 2 and 4mm less than the Rocky Mountain and Niner respectively, the Trek feels longer because the bars are that bit lower.
At the rear of the bike, it has the near-standard 435mm chainstays that are very common in this category. The bike uses 29″ wheels for all models except the extra-small in its range.
The bike uses Trek’s ABP suspension layout, and benefits from the clean silhouette that the design enables. It’s a very sleek looking bike, and that’s before you take into account the rather beautiful Bontrager RSL one-piece bars and stem that came on our test bike. The bars came in a very wide 820mm width, which we duly cut down, and has an effective stem length of 45mm. The 27mm rise bars are certainly elegant to say the least.
Another feature of this bike that Trek seemed to have got right is their integrated storage. Dare I say it, its door seems maybe one of the best executed of all the mainstream brands, and there’s ample volume inside.
Our bike came with a RockShox pairing for the suspension. A SID fork featuring their Charger Race Day Damper and an inline Deluxe shock covered damping duties. We ran the shock in its most open setting and found it to be very well damped for somebody that wants to push on. The fork was exemplary in terms of performance and really opens up what you can ride on a bike like this by giving adequate support. Truly, both the SID and the new 34 really do help bikes like this fulfill their potential. That said, our fork did develop bushing play, something that’s unfortunately happened before on other SID test forks.
The bike is also compatible with a longer 130mm fork. Assuming all other things are equal, the additional 10mm would reduce the head and seat tube angle by around half a degree. All the normal suspects are there in terms of frame spec. This includes internally guided routing, a SRAM UDH, and a bottle inside the front triangle. The bottle cage on this bike comes as standard.
The new Knockblock widens the range of the steering inputs and is an improvement on previous versions. However, I don’t feel it’s as well-executed as other brands’ offerings, mainly due to the fact that it uses keyed headset spacers that fit into notches in the stem. That means switching to a ‘regular’ stem requires a special adaptor, an inconvenience that doesn’t seem like it should be necessary.
The Top Fuel is a very good climber, even if it’s slightly heavier than something like the Santa Cruz Blur TR or the Rocky Mountain Element. It doesn’t ride like a heavy bike, but if you’re looking for all-out lightweight, this might be a very small stumbling block.
The bike is very surefooted and tracks very well, although I would say it’s more suited to people who want a bike that responds well to accelerations and surges in power, rather than having a very active suspension system that lets the wheel get up and over obstacles easily. It’s also very efficient. In fact, by our reckoning, it’s the most efficient bike on test.
On the technical climbs, it was very similar to the Rocky in terms of speed, but both were pipped by the ground-hugging missile that is the Santa Cruz Blur TR. For a bike that is so capable on the descents, though, the Top Fuel still packs a mighty punch when it comes to gaining elevation.
The one area it doesn’t shine is fit, for me at least, due to the longer and more stretched out seated climbing position. In some instances, it felt like this made it harder to get my weight over the bars, and made it feel slightly disjointed in tight, technical turns. Would a steeper a seat tube angle have helped? Possibly, but that could potentially diminish the bike’s comfort on flatter and more undulating terrain, so I understand why Trek chose the numbers they did.
The Top Fuel is a very capable descender, but its well-proportioned geometry is just half the story. It manages to strike a great balance between grip, tracking, and precision. The whole bike seems to just will you on to hit things faster and with more precision.
It damps the trail very well and is remarkably predictable and consistent. It offers a level of support that will really appease riders who are used to bigger bikes and want to ride this 120mm bike hard. That level of damping does mean that some riders might find it to be a little too firm, especially when riding rougher or more chattery trails.
In terms of the shootout at the more aggressive end of the downcountry spectrum, it’s perhaps not as supple off the top as the Element. The two bikes could be so similar, but they ride very differently. For steeper trails, I would say the Element has the edge, and if you hope to hang on to your friends on longer travel bikes, that could be the more suitable bike. However, if you intend to stick to trails more like the bikes were intended for, the Top Fuel would be my choice of bike.
The low front end of the Trek does put your weight further forward over the axle, but that comes back to you in flatter turns. The Trek has got a lot of personality, and it is a bike that not only inspires precise and confident handling but really encourages you to push on.
Ultimately, it felt like a 120mm tailor-made for someone that wants a short travel bike that excels on aggressive XC trails and is light enough to ride all day.