Trek Top Fuel 8 morphs from marathon racer to short travel trail ripper, but is there a high-octane ride beneath run-of-the-mill looks?
New Trek Top Fuel 8 is a short travel – 120mm travel front and rear – down-country trail bike with internal frame storage for both alloy and carbon models.
The Top Fuel has been a bit of a forgotten model in Trek’s range in recent years. Originally conceived as an XC race bike, it slowly morphed into a marathon bike around 2019, right about when mainstream XC race bikes became mainstream enough, and capable enough to go marathon racing on (see Trek’s Olympic and World Cup winning Supercaliber). Which made the Top Fuel kind of redundant.
Trek Top Fuel need to know
- 29in wheels on most frame sizes, but the XS gets 27.5in wheels
- 10 bike range starts at £2,600 and rises to £11,100
- Six frame sizes available
Understated, verging on vanilla, there’s nothing aesthetically that’ll make a passing rider rubberneck Trek’s new Top Fuel, but to write off this new short travel ripper at first sight is to make a big mistake. In fact the Top Fuel is the two-wheeled equivalent of a Q car (sleeper to our friends across the pond) – the kind of unassuming, run-of-the-mill executive saloon that flies under the radar, but packs a knock-out punch under the bonnet. The kind of car you use to rob a bank, in other words. But before I elaborate on this bike’s unexpected pace, let’s take a look at what’s new for 2022.
So now the Top Fuel slides sideways for 2022, aiming to slot into the best down-country mountain bikes shortlists. But whatever you call it, it’s trying to balance pedal efficiency with downhill capability in a package that’s more about fun than finishing first.
Backing up this role change is a raft of small but significant revisions to the Top Fuel. Firstly the geometry has seen a wholesale shift towards a better all-round balance between climbing and descending. The head angle has been slackened by 1.5º to 66º (the Mino link lets you steepen it back by 0.5º), and the reach has grown by up to 15mm depending on the frame size. Talking of which, there are now six, yes six, different frame sizes available, from S right up to XXL, making this one of the most comprehensive size ranges on the market. Trek has also steepened both the actual and effective seat tube angles to improve weight distribution for climbing, and it has increased rear wheel travel by 5mm to 120mm.
Geometry adjustment has been a feature on Trek’s bikes for a while now, but for 2022 the Top Fuel’s Mino Link has moved from the rocker link (other Trek’s use locate it in the upper seatstay pivot) to the lower shock mount. The reason for this is that Trek has moved to a Trunnion Mount shock for 2022 – it’s no longer upside down – reducing room at the rocker link. In its new position, the Mino Link is still easy to access and still gives you a head/seat angle change of 0.5º and a BB height variation of 5mm (the reach will also grow very slightly if you put the bike in the high/steep position).
Moving along, the Knock Block steering limiter has been made slightly less limiting. Previous models used a 58º radius, now that’s been upped to 72º, but the system retains its compatibility with standard stems and there’s clearance for the forks crowns, so it’s more about protecting the top tube from controls if you run a super racy cockpit. Trek has also made the move to a larger diameter 34.9mm dropper post in order to ensure better stiffness and a smoother action with modern long drop posts (some models come with a 200mm dropper on the largest frame sizes).
Perhaps the biggest news, however, is that Trek has found a way to incorporate its down tube storage system on the alloy models as well as the carbon ones. Not without some engineering head scratching, due to the difficulty of reinforcing specific areas of an alloy frame, this is a bit of a coup for Trek, since Specialized still doesn’t have SWAT on its alloy bikes. Included with the bike is a bottle cage and a neoprene pencil case inside the frame that can be used to hold your tools and a tube without them rattling around. And while we’re on the subject of rider-friendly features, the BB is now a threaded unit, and the carbon frames get tube-in-tube internal cable routing.
As the most lavishly specced alloy bike in the range, this Top Fuel 8 won’t set any pulses racing with its mix of Shimano XT, SLX and Deore components. However, it’s a functional collection of parts with the multi-release XT shifter being a standout selection, offering precise shifts and a nice rubber pad for thumb traction. The four-piston Shimano M6000 series brakes on our test bike were badly in need of a decent bleed, but offered plenty of power once we’d adjusted to their inconsistent bite point.
And while we’re moaning, we may as well raise the remote for the TranzX dropper post – slippery and difficult to position for ergonomic access, we’d be tempted to upgrade it with something from OneUp, Wolf Tooth or PNW.
How it rides
Trek has done a clever thing with the Top Fuel. Glance through the spec and you’ll see that there are basically two different shocks used across the entire range depending on whether it runs a RockShox fork or a Fox Fork. That means that the top of the line, XX1 AXS-equipped model at £11,100 will have exactly the same suspension characteristics as the £3,750 model I’m testing here. It’s levelling up in the truest sense, bringing the performance of the best models to the most affordable bikes in the range. And it also means Trek will have dialled the shock tune, since it has only had to do it for two different shocks, and not just the top model then hoped that the ride wasn’t too compromised with a lower-priced unit and a different damper bolted in. So you get a top spec RockShox Super Deluxe Ultimate RCT shock on this Top Fuel 8 with a pedal platform and three different low-speed compression settings for the open mode.
Up front there’s a RockShox SID fork with 35mm upper tubes and a basic Rush RL damper. Adjustments include a sweeping compression lever that gives you open through to locked modes and rebound via the pull-out knob at the base of the right leg.
I set the Top Fuel up with 25% sag at the rear and a firm 87psi in the fork (I weigh 76kg). The shock I ran in the most open of the three settings.
On the first climb out of the car park it was immediately noticeable how much softer and more comfortable the Top Fuel was than another 120mm travel, RockShox SID-equipped bike I’d ridden the week before. There’s more chassis movement both front and rear, so some energy is lost in the suspension, but it wasn’t so much that I instantly reached down for the pedal platform lever. Aboard the M/L size, the Top Fuel felt compact but not cramped, with a decent seated position over the BB. If you like a long bike and are of average height, definitely look at sizing up to the L frame, which has a 480mm reach, 15mm longer than the bike I rode.
Get out of the saddle in bottom gear to claw up a steep bank and the suspension really extends, which sounds bad, or weird, but actually feels spot on, because it lets the back wheel seems to dig into the dirt rather than spin when traction and power are poised on a knife edge. Bear in mind, as well, that I ran the bike in the most open setting, so changing the low-speed compression in the open mode, or making more use of the pedal platform, will produce a much firmer, sharper response.
My decision to set the Trek Top Fuel 8 up as open as possible was immediately rewarded on the first descent. The grip it generates is impressive, tracing every little contour of the trail with a hyperactive response. It’s incredibly supple, yet it also displayed a spooky ability to gain speed and accelerate just by loading up the suspension through dips and unweighing over crests. There’s a perfect amount of progression, giving up full travel, but never too frequently.
Being on the small side, my M/L Trek Top Fuel 8 was blessed with ridiculous agility. I could sling it into a series of direction changes and without emerging tied in knots, despite its very un-down-country-like 14.46kg weight. It was easy to set up for tight turns and contort through gaps, but the poise of the suspension let me hold it wide open on faster, more open sections. Equally the chassis and wheels seemed to have just the right amount of deflection to increase control in the rough and on off-camber sections without ever feeling like it was disconnected from my inputs.
Not as sharp or ruthlessly efficient as a YT Izzo, softer and more approachable than a Transition Spur, this new Trek Top Fuel brings high-octane entertainment and understated performance to the type of trails most widely ridden in the UK. Even if the looks might not leave a lasting impression, it’s unforgettable to ride.