"We race to build better bikes" is the motto at Trek. The Top Fuel is one of the models that have experienced the proximity to racing first-hand. If you look back two evolutionary stages in the product cycle, you will find the Top Fuel as a thoroughbred race bike on the tracks of the Cross-Country World Cups.
Fun downhill without strenuous summit tours
But a lot has happened since then. The Trek Supercaliber - a race bike with just 60 millimetres of suspension travel - replaced the Top Fuel on the racing circuit in 2019. Meanwhile, the engineers tailored the former race bike - the Trek Top Fuel - to the requirements of the still young down-country category: this bike category is intended to bridge the gap between the increasingly downhill-heavy trail bikes and emaciated race bikes. The idea is that pedal-happy touring riders will finally be able to enjoy fun descents again without having to lug overweight trail bikes to the summit. Most manufacturers rely on a recipe of around 120 millimetres of rear and front suspension travel, a telescopic seat post, grippy tyres and trail bike-like geometry. So much for the theory.
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Trek Top Fuel 9.8: Lightweight frame, expensive equipment
Unfortunately, the concept did not work out in practice, at least with the aluminium top fuel. Due to the aluminium frame weighing almost 3.5 kilos, the Top Fuel 8 ended up at 14.4 kilos despite its race genes. Added to this is Trek's radical pricing policy: for 4099 euros, the prestigious US brand still has to make do with heavy, second-class components. This puts additional pressure on the scales and cancels out the decisive added value compared to classic trail bikes. But now the motto is: new model, new luck. Will the down-country project succeed with a carbon chassis and just under 4000 euros more budget?
At 13 kilos, the Trek Top Fuel 9.8 GX AXS is certainly no lightweight in this category. However, the candidate has shed its sluggish character. The 1185 gram lighter carbon frame accounts for a large part of the weight saving. The bike owes the remaining 300 grams to its more expensive equipment. Nevertheless, the fact that the Americans only offer the Rockshox SID fork in the cheaper Select+ version for a bike costing € 8000 is bordering on extortionate. The fork not only spoils the price-performance ratio, but also has a negative impact off-road. Compared to its more expensive Ultimate counterpart, our test bike has to make significant compromises in terms of response behaviour. At 116 millimetres, the suspension travel is also shorter than specified.
But the Trek has a lot more to offer: Carbon wheels and handlebars, a radio-controlled Sram GX drivetrain and a lifetime warranty on the frame - it's a match made in heaven. The rear suspension with Deluxe Ultimate shock also does a great job. Our test riders were equally impressed by the responsiveness and absorption capacity.
The Trek Top Fuel likes fast corners
The developers also hit the mark with the riding characteristics. With its slack 66-degree head angle and long reach, the bike is able to charge purposefully through the terrain. Thanks to the very short 433 mm chainstays and the lower weight compared to the aluminium version, the Top Fuel 9.8 also makes fast cornering easy. The rear also offers sufficient support for pushing off jumps or pushing through berms. The voluminous Bontrager tyres allow low air pressures and thus increase comfort. Uphill, the steep seat angle positions the rider far forward on the bike, which puts pressure on the front wheel. The riding position of the Top Fuel is very compact. When pedalling out of the saddle, the rear end pumps noticeably when the shock is open. If you flip the platform lever, the rear end quickly calms down. In view of the Top Fuel's racing past, we would have liked at least a lockout on the handlebars for tough intermediate climbs.
Conclusion on the Trek Top Fuel 9.8 GX AXS by Max Fuchs, BIKE test editor:
The Trek Top Fuel presents itself in carbon guise as a harmonious down-country bike with reserves for the descent. Details such as the storage compartment in the down tube and the geometry adjustment round off the overall package in style. However, only the even more expensive models with high-quality components offer dream bike potential.
This is Trek
The largest US bicycle brand originated in 1975 in a shed in northern Wisconsin. In Waterloo to be precise. It was there that the two founders Richard Burke and Bevel Hogg began manufacturing steel frames for touring bikes. Today, highly developed performance bikes for road and off-road cycling are Trek's speciality. In the early years, the bikes were manufactured at the company headquarters in Wisconsin. Today, production takes place exclusively in Taiwan and China.
Technical data and notes on the Trek Top Fuel 9.8 GX AXS
Manufacturer information
- Price: 7999 Euro
- Available from specialised dealers
- Frame material: Carbon
- Frame size: XS / S / M /L / XL (tested in size L, 44 cm)
Measured values
- Weight without pedals: 12.96 kg
- Frame weight: 2309 g
- Weight of wheels: 4745 g
- Acceleration of running wheels: 3726 kg x cm²
- Handlebar width:: 780 mm
- Frame rigidity (absolute): 40 N/mm
Equipment
- Wheels: Bontrager Line Elite 30
- Tyres: Bontrager XR4 Team Issue; 29 x 2.40; Bontrager XR5 Team Issue; 29 x 2.50
- Fork: Rockshox SID Select+
- Shock: Rockshox Deluxe Ultimate
- Front/rear suspension travel: 116/124 mm
- Brakes: Sram G2 RS / 180/160 mm
- Gear system: Sram GX Eagle AXS 1x12
- Ratio/bandwidth: 30; 10-52 / 520 %
- Telescopic post / stroke / Ø: Bontrager / 170 mm / 34.9 mm
Valuation
- Driving behaviour uphill: 25.5 from 30
- Chassis efficiency: 15 out of 20
- Rolling resistance: 12 out of 15
- Weight: 10 from 20
- Inertia impellers: 5 out of 10
- Bottle cage: 5 out of 10
- Driving behaviour downhill: 24 from 30
- Front suspension: 10.5 out of 15
- Rear suspension: 15 out of 20
- Saddle retractability: 10 out of 10
- Brakes: 11.25 out of 15
- Tyre grip: 12.75 out of 15
- Driving stability: 5 out of 10
TOTAL UPHILL: 72.5 OUT OF 105
TOTAL DOWNHILL:: 88.5 OUT OF 115
- Other: 26.75 out of 30
- Ease of maintenance: medium
BIKE test rating*: very good - 187.8 out of 250 points
*The BIKE judgement reflects the laboratory measurements and the subjective impression of the test riders. The BIKE judgement is independent of price.
BIKE judgements: super (250-205 P.), very good (204.75-170 P.), good (169.75-140 P.), satisfactory (139.75-100 P.), with weaknesses, unsatisfactory.
Max Fuchs
Editor
