First Ride: Trek Top Fuel 9.8 SL
For years, the Trek Top Fuel was the company’s World Cup-winning, 26-inch-wheeled cross-country race bike. But then the big wheel craze hit, and the Top Fuel was replaced by the 29er Superfly FS. For 2016, the Top Fuel came back to reclaim its place at the top of the line as the company’s superlight race bike, with some notable improvements over both of its predecessors.
What’s New
The most obvious update is wheel sizing. Trek employed what it calls Smart Wheel: The 15.5-inch Top Fuel gets 27.5-inch wheels, while 17.5-inch sizes and up are 29ers. As Trek explains it, the ideal XC racing position is anywhere from a 42- to 45-degree bend at the torso, though World Cup racers get even lower with 41- to 43-degree angles—a position that enables the rider to recruit the most power from the glutes. Ross Rushin, assistant mountain bike brand manager at Trek, says, “No matter what we did, we could always get the hand position about 30mm lower with a 27.5-inch wheel on the 15.5-inch frames. We found that the ability to better achieve that target fit makes up for the slight loss of rolling speed from going to smaller wheels. The other advantage with smaller wheels for that smaller rider is that they can lift that front wheel more, to better maneuver and control the bike, and that makes up for speed, too.”
Like the last rendition of the original Top Fuel, the 2016 version sports 100mm of front and rear travel, the latter of which is delivered by the company’s Full Floater Evo link design, which attaches the shock to two moving points on the down tube. Trek says this design enables the suspension to stay more active and plush-feeling than the swing link system attached via the top tube of the Superfly FS. Trek also says that, because the rocker link provides a more solid connection between the front and rear ends of the bike, it improves overall frame stiffness from the Superfly, even if it does mean the Top Fuel is 30 grams heavier. Based on numbers provided by Trek, the Top Fuel is 9 percent stiffer in the head tube area and 16.1 percent stiffer in the bottom bracket area than the Superfly FS. “We were okay with not losing weight because the Superfly FS was already lighter than anything out there,” says Rushin. (And indeed, our 15.5-inch Top Fuel tester weighed a scant 22.9 pounds on our scale—impressive for a $5,000 bike.)
RELATED: Editors’ Choice: Scott Spark 910
Other notable changes that primarily affect the 29er versions: Chainstays were shortened for more agile handling, going from 452mm on the Superfly FS to 435mm on a 29er Top Fuel—only 9mm longer than the chainstays on the 15.5-inch, 27.5-inch version. This was enabled by the wider hub spacing that came from using Boost hubs on the 29-inch versions of the Top Fuel. Boost also stiffens the wheels, says Trek, addressing a common criticism of 29ers that the wheels were too flexy. The bike comes with Trek’s Mino Link switch that gives you up to a degree of adjustability in head and seat tube angles, and half an inch in bottom bracket height. And Trek’s Control Freak cable routing system allows you to cleanly internally (or externally, if you wish) route up to 54 combinations of cable setups for droppers, braking, and shifting systems.
How It Rides
I rode the 15.5-inch, 27.5-inch version of the Top Fuel over two weeks, on some fast group rides over techy East Coast singletrack, as well as in an XC race that featured a variety of terrain: flow trails, grassy fire roads, lots of logovers, and rock gardens.
I still hear some people say that hardtails are faster on climbs, but I’d pick a light, efficient-climbing, full-suspension model like the Top Fuel over a superlight hardtail any day. About a month prior to racing on the Top Fuel, I did an XC race on a 21.5-pound, carbon 29er hardtail on a very similar, if less technical, course. I felt much faster on the Top Fuel (and my pace confirmed it) despite the extra pound and a half of bulk, and the smaller wheels. I’ll chalk it up to the additional traction on the uphills, improved descending capability, and the generally more forgiving ride on the Top Fuel.
Fitted with DT Swiss XMC1200 carbon wheels and weighing just under 23 pounds, the Top Fuel 9.8 SL was a joy to climb on. The bike punched it up climbs when I laid down the power, and during fast pedaling on flats, it felt like it was transferring all my power immediately and efficiently. I raced on tired and sore legs, and the Top Fuel made easy work of the uphills, going fast enough for a win in my category that day. Another tester rode the bike on her home trails and got several Strava PRs on it. I did notice the slightest bit of pedal bob on the road when the shock was fully open, but it didn’t seem to affect the quick feeling of the bike on the trail.
Small-bump performance was excellent, resulting in surprisingly great traction despite the Top Fuel’s low-profile, 2.2-inch Bontrager XR2 Team Issue tires—almost on par with the excellent Yeti SB5c Beti I rode recently, which has the best traction of any trail bike I’ve tested, and rolls on bigger tires. On one ride, the rocks were snotty and slippery from rain that had fallen earlier that day, yet the Top Fuel crawled resolutely uphill over slick boulders and rock gardens, helping me to keep up with faster riders primarily riding trail bikes.
After getting off a more traditional trail bike, the narrower, 680mm handlebar paired with the 70mm stem—though appropriate for an XC race bike—took a little getting used to. The bike handled a bit quicker than I was ready for at first, but within half a ride, I was accustomed to it. Once I got used to how responsive the Top Fuel is, I found it steers very precisely, deftly shooting through skinny gaps between pedal-menacing rocks, and sticking the right line during techy sections that required lots of concentration.
In designing the bike, Rushin says Trek considered the fact that World Cup XC courses are getting more technical and challenging, and so the Top Fuel needed to be more capable than it had been in the past. I found the Top Fuel to be surprisingly good—for a 100mm-travel bike—at descending rocky, East Coast singletrack at speed, including a few very steep, rutted, and bumped-out sections. I felt like the suspension did firm up a bit when I sped up over very rough terrain, leading to a sense of being a little jostled on the bike, but the Top Fuel was stable enough to stay on its line; this descending personality seemed appropriate for an XC race machine. And the suspension sported some nice pop, making it super fun to catch a little air over rocks and small rollers.
As for wheel size: With its speed and XC-oriented feel, this bike’s personality seems suited to 29-inch wheels. However, while you lose that extra rollover capability with the smaller bike, another tester and I agreed that this 27.5-inch bike was particularly easy to pick up and loft over logs and big rocks anyway. While I am curious to try a 17.5-inch 29er, there was nothing slow-feeling about the 27.5-inch version of this bike—and it was good enough to help me win a race.
The bike ships in its slacker, low setting, in which I performed all my test rides. The stock setting gives the Top Fuel a 69.9-degree head angle, a BB height of 13 inches, and a seat tube angle of 69.5 degrees. Flipping the Mino Chip to its higher, steeper geometry brings the head tube angle to 70.9 degrees and the seat angle to 70.5 degrees, and raises the BB height to 13.4 inches. In the low setting, I did find myself just barely grazing my pedals in a couple of surprising places, like fast, off-camber corners. Getting an extra 0.4 inches of BB clearance could reduce that, though I really didn’t find it to be a significant issue either way.
Parts are solid: The SRAM X1/X01 1x11 drivetrain gets a 32T chainring up front and a 10-42 cassette in the rear, and I enjoyed smooth shifting and the ability to quickly dump multiple gears when I hit a sudden steep climb. The Shimano XT brakes worked great, too. I did miss two things: One, even on an XC race bike, I wanted a dropper post. And two, while the remote lockout on the handlebar for the fork and shock makes it convenient to open and lock the suspension during a fast-paced riding situation, both myself and our other tester wished there were some middle “trail” mode in addition to fully locked and fully open options. The only time I lock both front and rear suspension is when I’m climbing on the road; but if I’m on the road (or hopping onto the trail from the road), it’s not as hard for me to reach down and flip the settings on my fork and shock anyway.
But these two points are overshadowed by the big picture: For $5,000, you can have a carbon XC race bike that weighs just a shade under 23 pounds for the smallest size, and is fast because it’s capable, not just because it’s superlight. Who should consider buying the Trek Top Fuel? XC racers, of course, but also anyone who most prizes lightweight climbing prowess in a short-travel, full-suspension package. Whether you’re pinning on a number or just trying to rack up some bragging rights on Strava, you’ll ride fast on the Top Fuel—and really, who’s not a fan of that?
Price: $5,000
Weight: 22.9 lb. (15.5 in.)
You Might Also Like
