In previous iterations, the Top Fuel has been a competitive cross-country race bike with 100 mm suspension travel and only the lightest components available at each price point. We reviewed that bike last year, and found it to one of the best at this brief. The new Top Fuel tries to retain parts of this racing heritage but at the same time adapt to become more versatile with a more balanced geometry and components that are more capable for versatility on trails.
The New Bike
So what has Trek changed to achieve this? In short, almost everything about the bike.The new frame has been bumped up to 115 mm travel in the rear suspension with Trek fitting a 120 mm travel fork from the factory. The Top Fuel can also be ridden with a 130 mm fork.
The Top Fuel no longer uses the traditional Full Floater design (despite a curious decal on the bike still using the name) seen on the previous Top Fuel and other Trek mountain bikes. Where the shock is mounted to the stays on a Full Floater setup to form a single rear triangle unit, the shock on the new Top Fuel now mounts directly to the base of the downtube. The aim is to improve frame stiffness with the added benefit of making the cable routing much neater. Gone is the unsightly looping lockout cable for the shock, which is now positioned 'upside down'. Although Trek has done away with the traditional Full Floater design, the Active Braking Pivot (ABP) remains. The ABP is found around the rear axles and aims to keep the suspension active and responsive under braking. One downer for those participating in long distance events is that the suspension design dominates much of the front triangle leaving insufficient space for a second bottle cage.
Trek has continued to offer the Mino Link chip for adjusting the geometry between a Low and High setting on the new Top Fuel. The chip has moved from being in the chainstay to the front (at the shock mount) of the redesigned rocker link. The Top Fuel ships in the Low setting, so the numbers mentioned above are quoted in that position.The frame geometry is another stark departure from the previous Top Fuel. The short and sharp cross-country geometry of yesteryear has been replaced with numbers suited to the bike's new found purpose. Some headline numbers include: a 67.5 degree head angle, effective seat tube is 75 degrees, chainstays measure 435 mm, and reach on the medium-large frame is 456 mm with a 1168 mm wheelbase. A far cry from the Top Fuel of old but well positioned for the Top Fuel’s new found versatility.
Trek Top Fuel Geometry
The new Top Fuel is available in either Alpha Platinum Aluminium or OCLV Mountain Carbon. Unlike some Trek carbon frames in the past where parts of the rear triangles were aluminium in the midrange, the new carbon Top Fuel frames are carbon throughout the range.The new frame implements Trek’s Straight Down downtube which promises extra stiffness without any weight compromises. Partly because of this straight downtube, the bike also carries over the Knock Block technology in the stem to prevent the fork and handlebars from crashing into the frame and causing damage. Despite rumours of Trek’s new bikes ditching the PressFit bottom bracket standard for a T47 threaded type (this might still come), the new Top Fuel remains a 92mm PressFit setup.
2020 Trek Top Fuel 9.8 Specifications
- FrameOCLV Mountain Carbon main frame & stays, tapered head tube, Knock Block, Control Freak internal routing, Carbon Armor, magnesium rocker link, Mino Link, ABP, Boost148, 115mm travel
- ForkFox Performance 34 Step-Cast, Float EVOL air spring, GRIP 2-position damper, TwistLoc remote, tapered steerer, 44mm offset, Boost110, 15mm Kabolt axle, 120mm travel
- ShockFox Performance Float, 2-position DPS damper, TwistLoc remote, tuned by Trek Suspension Lab, 190x45mm
- WheelsBontrager Kovee Elite 30 carbon, Tubeless Ready, 54pt Rapid Drive, Boost110 front, Boost148 rear
- TyresBontrager XR3 Team Issue, Tubeless Ready, Inner Strength sidewall, aramid bead, 120tpi, 29x2.40"
- ShiftersSRAM GX Eagle, 12 speed
- Rear DerailleurSRAM GX Eagle
- CrankTruvativ Descendant 7k Eagle DUB, 32T alloy ring, Boost
- Bottom BracketSRAM DUB, 92mm, PressFit
- CassetteSRAM XG-1275 Eagle, 10-50, 12 speed
- ChainSRAM GX Eagle, 12 speed
- SaddleBontrager Montrose Elite, titanium rails
- SeatpostBontrager Line Elite Dropper, internal routing, 31.6mm
- HandlebarBontrager Line Pro, OCLV Carbon, 35mm, 15mm rise, 750mm width
- StemBontrager Kovee Pro, 35mm, Knock Block, Blendr compatible, 13 degree
- HeadsetKnock Block Integrated, sealed cartridge bearing, 1-1/8" top, 1.5" bottom
- BrakesetShimano SLX M7000 hydraulic disc, 180mm front rotor, 160mm rear rotor
- Claimed weight (Size Medium)11.84 kg
- Measured weight (Size Extra Large)12.47 kg (with sealant)
- Retail PriceR 89,999
The Top Fuel 9.8 model uses Fox suspension while so other models prefer RockShox. The excellent Fox 34 Step-Cast Performance fork is paired with a Float DPS shock. The fork and shock both have 2 position dampers, open or closed. These are controlled simultaneously by a RockShox TwistLoc remote lockout which also helps to reduce clutter in a busy cockpit.
The cockpit boasts a range of Bontrager components. The handlebar is carbon measuring 750mm wide with a stem length of either 60mm or 70mm depending on frame size. The stem is designed to be flipped to either have a positive 13 degree angle or a negative 13 degree angle, depending on rider preference. The dropper seatpost is a Bontrager Line Elite with 100, 150 or 170 mm travel, depending on the frame size, with a Montrose Elite saddle perched on top.The wheels and tyres are also from the Bontrager stable with a Kovee Elite 30 carbon wheelset and the recently revamped XR3 Team Issue tyre. Trek has elected to fo with 2.4 inch width tyre across the range. These pair well with the 29mm internal diameter of the Kovee rims on the Top Fuel 9.8.
The drivetrain is SRAM’s mid-range GX Eagle groupset with a Truvativ crank and 32 tooth chainring. The frame officially supports up to a 34 tooth chainring. Shimano’s renowned SLX M7000 brakes attend to the stopping.
On the trail
It is worth noting that I first received the Top Fuel a few weeks before the official launch date so while I did manage to get in a good number of rides, not all aspects of the bike have been tested as thoroughly as others.
When I headed out for my first ride, the details about the new bike were not yet available so I went into it knowing nothing about the bike other than it was a Top Fuel. It was obvious on first viewing that this not simply an updated regurgitation of the same Top Fuel. The Fox 34 SC fork, dropper seatpost, and 2.4 inch tyres being the first signs of something different. It was a novel experience heading out for the first ride not already having jumped to conclusions based on the geometry chart.
Heading into the first climb, I was still making comparisons to what I knew of the old bike and was somewhat puzzled. With the suspension open in the Low geometry setting, the bike wallowed noticeably more than the old bike, not an improvement at all, but locking it out made more sense as the bike encouraged you push on harder. I was not quite sure what Trek are trying to achieve. Dropping into the first trail and everything suddenly became very clear where Trek are going with the new Top Fuel. It is nothing like the old bike.
Admittedly, I’m a big fan of cross-over short travel 29ers. Look no further than my reviews of the Specialized Epic EVO, Scott Spark, and even the Transition Smuggler. But with these bikes, there was always some compromise, a leaning towards either being more cross-country or more trail orientated. The Top Fuel is the first bike that I’ve ridden that appears to achieve a near perfect balance between both worlds.
The Top Fuel starts with a dedicated frame for the 115 mm travel and a well-considered geometry. It’s not an XC frame kitted with a longer fork or a trail-focussed suspension design hoping to pass off as pedalling friendly. The component selection is also important for the Top Fuel’s balance. The Fox 34 SC was developed exactly for type of riding the Top Fuel is hoping to produce and does the job with excellence. The XR3 Team Issues tyres seem to have been made specifically with the new Top Fuel in mind, with their fast rolling pattern in the centre, knobs on the outside, and a wide 2.4 inch platform that offers stability and grip. The Kovee rims with a 29 millimetre internal width accommodate the XR3 tyre perfectly. The cockpit is also a happy medium between bar width and stem length.
Climbing the bike with the Mino Link setting in Low, the suspension is noticeably active on the climbs when left open. There is obvious movement as you power up a hill. Jumping out of the saddle for a burst of power and the bike does wallow considerably. If the climb is rough, however, the open suspension offers supreme grip as you clamber of roots or loose rocks.
Flipping the Mino Link into High mode (it's an easy two minute change), not only makes the geometry slightly sharper and shorter but also improves the peddling characteristic of the bike. The suspension feels firmer, dipping less into the travel under pedalling force than in the Low mode, giving the overall impression of greater efficiency. My time in the High setting was limited but it certainly appears to be the mode you would want the bike in for any serious marathon excursions.
For those who tolerate no movement on the ups (in either Low or High mode), twisting the grip shift lockout into closed is where you will want to be for climbing. The bike is forced to sit higher in the travel which places you better in a better position above the pedals. The frame feels impressively stiff and attentive to the rider’s every ounce of input. Like a sudden change of character, the bike feels more like the outgoing Top Fuel. It implores you to give it your all. The new Top Fuel is an impressively firm platform (which pays off on the downs too) and, when locked-out, it feels like every little watt of input is being used to power you forward.
The new Top Fuel is a blast on the descents. The new frame is immensely stiff which translates into a precision handling ride. The carbon wheels, Fox 34 SC, and even the 35mm diameter stem and handlebar interface help the Top Fuel achieve this feeling off handling accuracy. The result is a bike that tracks through turns with exactness, snapping you out of a long berm true and fast. It’s the same effect on jumps, with a natural pop that encourages you to boost off the lip. The bike also holds a line in the rougher stuff. With the ability to launch into (smaller) rock and root gardens without fear of being bashed off course.
Where the Top Fuel really elevates itself above an XC bike on the trails is the good feedback from the suspension. Early in the travel you can feel that the bike is invested in absorbing the smaller roots and rocks, maintaining grip excellently in chattery conditions. On the bigger hits, there is a noticeable ramp up as you reach the end of the travel. It’s not a bottomless feel like some trail bikes but it definitely eases you into the end of the travel. It is vastly improved feel over the old Top Fuel and many other cross-country bikes where the feedback is so vague that you can only guess about what’s happening with the suspension. The suspension pairs well with the widish 2.4 inch tyres with the extra volume (and lower pressures) clear offering up some additional dampening. The general sensation is a fast but secure bike that loves hurtling down the trails at speed.As mentioned, the Fox 34 SC is the go to fork for a short travel bike like the Top Fuel. The dedicated 120 mm platform provides ample stiffness with a suspension tune and weight that really suits both the XC and trail worlds. And there is little reason to scoff at the Performance level fork, it’s superb.
It was a trip to Jonkershoek, my favourite testing ground, where the versatility Trek really impressed me. More specifically, the infamous Saaltjie climb (around 7 km and 500 metres) and the red-rated Armageddon trails (4.5 km and 500 metres) down is the perfect test for an XC/ Trail bike cross over. I twisted the bike into lockout and proceed to take the long forestry road climb. The Top Fuel felt efficient throughout and, to my surprise, it got me to the top with a personal best time. Of course, the new Top Fuel, with its aspirations of versatility is always going to be around a kilogram or so heavier than a focussed XC bike but other than that, it does not feel far off. Dropping into the Armageddon trail reinforced what I’ve described above. The Top Fuel can hold a line in the rough stuff while still maintaining a cross-country bike style of agility. An aspect that is often overlooked by endurance racers is how taxing descending can be on a focussed race bike. On the Top Fuel, I came to the end of the long Armageddon descent feeling surprisingly fresh, ready for the next climb.
So who is the new Top Fuel for?
For starters, simply anyone who enjoys mountain biking should enjoy the Top Fuel. But it will better suit riders that want to take part in cross-country/ marathon type events but also enjoy the pleasure of simply riding trails for the fun of it, maybe even the odd enduro race. From my anecdotal observations on the trails and at races, there are a substantial number of riders that could fall into this description and I think that the Top Fuel could prove to be a one bike solution for many of these riders.
That said, it’s not going to satisfy the more burly trail or enduro rider. The Top Fuel is still best suited to a cross-country serving of gnar. But if you roll with such riders occasionally, the bike will certainly try its hardest to take the blows. On the opposite end of the spectrum, the Top Fuel will also not appease the obsessive weight savings and uncompromising pedalling efficiency need of the competitive cross-country crowd.
The new Trek Top Fuel balances the needs of riders who want efficient pedalling while still enjoying the ride on the fun technical descents. If you're entering marathon races and want to get more pleasure and confidence on the single track or you are simply a rider that appreciates getting to their local trail head with haste and enjoying the ride coming down to fullest, then the Top Fuel is the ultimate box ticker.