Issue #040, Review - October 11, 2019

Trek Top Fuel 9.9 in review

The original Trek Top Fuel was a pure-bred race machine, designed for maximum speed at the expense of versatility and comfort. This year, the Trek Top Fuel has had a ground-up makeover, adding more travel, slacker geometry, more clearance, and most importantly a change in attitude from XC-whippet to all-round shredder.

For an overview about the test field click her: The Best Short-Travel Trail Bike – 6 Mountain Bikes in Test

**Trek** Top Fuel 9.9 | 120/115 mm | 11.4 kg | € 8,999

With 120/115 mm of travel and a full carbon frame, the 11.5 kg Trek Top Fuel 9.9 is the lightest bike in this group test. At € 8,999 it’s also by far the most expensive. Compared to the old model the differences in geometry are startling, with a whopping 2.5° shaved off the head angle and a 1° increase in seat tube angle. Combined with the longer reach, the new Top Fuel 9.8 is a very different beast. Trek’s signature Full Floater suspension has gone, replaced with a fixed lower shock mount to improve frame stiffness and increase clearance to fit a 29×2.4” tire. The top of the line, 9.9 spec tested is dripping with super bling components too. With a Fox 34 Factory SC EVOL fork and Factory DPS shock, 29” Bontrager Kovee Pro 30 carbon wheels and a full SRAM XX1 Eagle drivetrain, there is nothing left to be desired. Premium weight savings continue with SRAM’s featherweight Level Ultimate brakes with 180/160 mm rotors. However, as expected the small 160 mm rotor lacks bite and control. Finished off with a carbon cockpit, this is a dream build, but is such a low weight too much of a compromise?

We love how the Trek Top Fuel darts through corners. However the tangle of cables at the front is less appealing.

**Helmet** Troy Lee Designs A2 | **Glasses** Oakley Race Jacket PRIZM | **Jersey** Troy Lee Designs Checkers SS | **Shorts** Troy Lee Designs Ruckus

The Trek Top Fuel 9.9 in detail

Fork Fox Factory Float EVOL 34 Step-Cast TwistLoc remote 120 mm
Shock Fox Factory Float DPS damper, TwistLoc remote 115
Brakes SRAM Level Ultimate 180/180 mm
Drivetrain SRAM XX1 Eagle, 12 speed
Seatpost Bontrager Line Elite Dropper
Stem Bontrager Kovee Pro 35 mm
Handlebar Bontrager Line Pro, OCLV Carbon, 35mm
Wheels Bontrager Kovee Pro 30 carbon
Tires Bontrager XR3 Team Issue 2.40″

**Birds nest**
While the TwistLoc lockout works exceptionally well, it’s only really needed in a race environment and adds a lot of ugly cabling

**GripShift activation**
The TwistLoc lockout is similar to a grip shift. Simply rotate the shifter to lock out the fork and stiffen the rear suspension, then hit the button to release again.

**Knock Block**
The ‘Straight Shot’ downtube adds stiffness and a clean aesthetic, but also needs the ‘Knock Block’ steering limiter to stop the forks hitting and potentially damaging the frame.

**Sublime suspension**
Trek have moved away from the Full Floater suspension design, now attaching the shock to the down tube. The new system is superb, offering maximum support and control.

**Rapid acceleration**
The 29” Bontrager Kovee Pro 30 carbon wheels move like a scalded cat. Even the smallest pedal inputs propel you forwards.

Size	S	M	L	XL	XXL
Seat tube	394 mm	419 mm	470 mm	521 mm	750 mm
Top tube	564 mm	599 mm	632 mm	651 mm	676 mm
Head tube	90 mm	90 mm	100 mm	110 mm	120 mm
Head angle	67.5°	67.5°	67.5°	67.5°	67.5°
Seat angle	75°	75°	75°	75°	75°
Chainstays	435 mm	435 mm	435 mm	435 mm	435 mm
BB-Drop	36 mm	36 mm	36 mm	36 mm	36 mm
Wheelbase	1.117 mm	1.152 mm	1.186 mm	1.207 mm	1.234 mm
Reach	405 mm	440 mm	470 mm	487 mm	510 mm
Stack	594 mm	594 mm	603 mm	612 mm	621 mm

The Trek Top Fuel 9.9 on the trail

So how does it ride? In one word – fast! Pickup in the freehub feels almost instantaneous. Dab the pedals and you’ll enjoy a sharp kick of acceleration from the lightweight wheels. Smash down on the cranks and it leaps forward like a bullet from a gun, both uphill and downhill. A RockShox TwistLoc controller, similar to a grip shift, allows you to lock out the fork and increase compression on the rear shock with a flick of the wrist. While it does work intuitively, we found it of little use for fun trail riding, and the additional front cabling looks a mess. Out of the corners and sprinting up sharp pitches the Trek is unrivalled, but with the lightest wheels and lightest overall build it was always going to score well here.

**Tuning tip**
For trail riding, we would spend some time wrapping and organising the excess of cables at the front of the bike, or even remove the TwistLoc lockout altogether.

What came as more of a surprise was the Trek’s potency on the descents. Adjustable geometry lets you bias the bike towards up- or downhills but we ran the bike predominantly in the low flip chip position, enjoying the more composed handling. The steering is impeccable precise, allowing you to knife though corners and skip over roots and rocks. Nimble and lively, the Trek’s suspension delivers just enough travel to keep you comfortable without using a single millimeter too many. Even when straying onto very technical trails, the Trek offers superb support, remaining firm without ever feeling harsh. On dry hardpack the small knobs of the Bontrager XR3 Team Issue tires roll incredibly fast but they’re not a versatile option quickly losing grip in the wet. If your rides consist of all-day mountain missions, the Trek Top Fuel is not the most comfortable cruiser and prefers confident riding and a firm hand at the controls. However, if you enjoy the simple pleasure of crushing climbs and making the most of every descent, the Trek Top Fuel is your passport to a world of fun.

With a suspension system that always uses just the right amount of travel without feeling wallowy or lazy and a very balanced geometry, the Trek Top Fuel is a hard-edged but versatile machine. It is more than capable of delivering KOM’s both up- and downhill. The flyweight build kit inevitably increases its cost, but has some definite advantages on the trail.