If the ride characteristics of a bike can be traced directly to the region in which it was developed, then the traits of the Trek Fuel EX 9.9 should come as little surprise given its Midwestern roots—it's dead-reliable and consistent, if not a touch conservative.
Bred south of Marquette in Waterloo, Wisconsin, the 130-millimeter-travel 29er is an adept, modern trail bike, delivering dependable ride quality on a variety of terrain, the result of Trek's quick-responding ABP suspension platform coupled with its RE:aktiv shock. The EX 9.9 is the only Fuel model currently available with Trek's new Thru Shaft shock technology, designed with Penske Racing to reduce lag by eliminating the oil volume displacement that occurs when the shock compresses. The effects of Thru Shaft were most evident in the chunky rocks on the inaptly named Flow trail, where the shock's ability to recover from impacts is paramount to maintaining speed and control.
The Fuel's 67.7-degree headtube angle and 74.7-degree seat-tube angle (in the high geometry setting) are evenly matched, giving it a balanced and maneuverable feel—despite its large wheels, the Fuel was easy to move around, its tires eager to leave the dirt. The Fuel screams uphill, aided by a light and agile chassis and superb rear-wheel traction that makes powering up and over successive rocks practically painless. But one tester felt that it was too conservative, perhaps targeted at the rider who isn't looking to push the bike beyond its limits, and would have preferred at least a 140-millimeter fork to give it a more aggressive demeanor on descents.
The 9.9 build we tested is expensive and spares very little on parts as one would expect when investing $8,400 in a toy—it sports a SRAM XX1/X01 Eagle drivetrain, carbon wheels, Fox Factory Kashima-coated suspension and SRAM Guide Ultimate brakes, weighing a scant 26 pounds—although we'd prefer to see a 150-millimeter dropper post on the size 17.5 instead of a 125. One tester noted that the side knobs of the Bontrager XR4 tires felt under-gunned and that the 750-milleter-wide bars are too narrow, making the Fuel feel more XC-like than trail.
Don't let the price of the 9.9 scare you away—the Fuel EX is available in a complete build with an aluminum frame starting at $2,100, and if you aren't in a hurry, the Thru Shaft technology is likely to trickle down to lower-priced models in the coming years. That's a solid value regardless of where you're from.
Q&A with Travis Ott, MTB brand manager of Trek Bicycles
The biggest change to the Fuel EX this year is the addition of the Thru Shaft technology in the rear shock. How will this benefit riders, and why should they consider shelling out more money for it, especially when the next model down, the Fuel 9.8 (without Thru Shaft), costs $3,000 less?
The shock is amazing, but it's not $3,000 amazing. Nearly all of that $3,000 upcharge to the Fuel EX 9.9 is buying you the best spec we could gather. Carbon wheels, better fork, SRAM XX1 Eagle drivetrain, SRAM Guide Ultimate brakes, carbon components, and a carbon chainstay.
The RE:aktiv with Thru Shaft shock is outstanding and worth shelling out a few extra dollars. It will affect your ride experience more than any other upgrade. Because of its unconventional design that eliminates the internal floating piston and the lag associated with it, it simply works faster than anything else out there. Your rear wheel will feel glued to the ground and you won't feel it struggling to keep up as you charge through rough sections.
With trends shifting toward more travel in the front than in the rear, especially among bikes in this travel range, why has Trek opted to keep the Fuel's travel evenly balanced?
Overforking can help slacken the bike or make it feel more capable and create a bias for descending. Fuel EX wants to pedal just as well as it descends, and further, it does not need to do overfork for sake of geometry nor capability. The bike's frame is already massively stiff and capable. The stock 67.7-degree headtube has the ability to slacken with MinoLink adjustable geometry if that's what you're after.
If you want a trail bike that has a bias for descending, I'd point you to the Trek Remedy with its 160 millimeter front and 150 millimeters of rear travel.
The Fuel EX has undergone multiple geometry and frame changes over the past several model years, do you feel like it's now hit its sweet spot in 2018? Why?
It's in a great spot right now. Geometry is confidence inspiring but handling is still lively. For people looking for a bike that descends and pedals equally well, it has a lot of capability they can tap into when needed, but handling and pedaling is still lively enough for when the terrain isn't pointed downward.
The Women's version of the Fuel in 2018 has a different-shaped toptube, presumably to lower standover height. Last year, the women's Fuel frame was the same as the unisex model, though Trek has used a swoopy toptube on previous women's bikes. Why the change now, particularly in light of the industry's larger shift back toward using the same frames for both genders?
Fuel EX Women's comes in 4 sizes. (14, 15.5, 17.5, 18.5-inch). The larger two sizes use the same frame as the mainline model. The smaller two sizes use a dipped toptube to get more standover. We received consistent feedback last year that smaller riders needed more standover. We make every bike, every size the best bike possible. Every rider deserves a bike optimized for him or her, not just the perfectly average.