Last year, Trek introduced a totally redesigned trailbike with their 4.7-inch-travel Fuel EX line featuring their Active Braking Pivot (ABP) and Full-Floater suspension. We raved about the aluminum-framed EX 9, but felt something had been lost in the translation with the carbon fiber-framed Fuel EX 9.5. Trek seems to have agreed.

New for 2009, the flagship carbon fiber Fuel EX 9.9 replaces the aforementioned EX 9.5 in the lineup. Trek offers six Fuel EX models that utilize the ABP and Full-Floater suspension, ranging in price from $2310 to $7149.

WHICH COMPONENTS STAND OUT?
Fox takes care of both the front and rear suspension duties on this quintessential trailbike. The EX 9.9 features a custom-tuned 4.7-inch-travel Fox RP24 fork with a four-position platform and E2 tapered alloy steerer. The shock is a custom "trail tuned" Fox Shox Float RP23 XV air shock with ProPedal. The cockpit components are all Bontrager, while the frame's tapered head tube utilizes a Cane Creek Frustum SE Light headset.

 

HOW DOES IT PERFORM?
In the saddle: The EX 9.9 is a beautifully crafted bike, and the carbon fiber Bontrager handlebar and seatpost stand out immediately. The first time you hop aboard the all-new Fuel EX 9.9, you'll appreciate the comfortable Bontrager Race X Lite saddle and slim Bontrager lock-on grips. The combination of the slightly rearward weight bias and a 25-inch-wide handlebar conjures up memories of last year's EX 9.5 trailbike.

Pedaling performance: On your first ride aboard the EX 9.9, you won't be 50 yards from the trailhead before you realize you're aboard a special machine. The key to the EX's pedaling performance is the ABP and Full-Floater suspension. It efficiently propels you forward with each pedal stroke, even with the ProPedal lever in the off position. The EX 9.9 carries momentum so effortlessly you'll feel like you're having one of those superhuman days in the saddle when you want to drop the hammer and do another lap.

When spinning along on mildly smooth terrain, popping through the gears is a cinch, and the SRAM and Shimano drivetrain goods work together with ease.

Cornering: The Fuel EX 9.9 has remarkably balanced suspension, which allows you to pin it into a corner and drive the wheels into the turn for traction. The rather unassuming 2.25-inch Bontrager Jones XR tires appear to be designed to roll fast. However, they have some serious bite when turning at speed. It takes a couple of rides to completely trust them, but they will win you over. We got the best all-around results running the Jones XR tires with 30psi in the rear and 28psi in the front. Optimum tire pressure varies according to rider weight, but for a medium-sized person (about 165 pounds) riding a medium-sized frame (17.5 inches), our recommended settings are a good starting point.

The 25-inch-wide Bontrager handlebar felt too narrow and limited the amount of leverage we could put on the front end. The EX 9.9 handles direction changes nicely, but could be even better with a 26- or 27-inch-wide handlebar.

Climbing: At just 25 pounds, the Fuel EX 9.9 rockets uphill. As we mentioned before, most climbs are more than feasible with the Fox RP23 shock's ProPedal feature in the off position. Not only does this make for a smoother ride, but it also increases traction on very technical terrain.
Should you be in the saddle for an extended period of time on a smooth, hardpack trail, the ProPedal feature does offer undeniable improvements in acceleration, but applying the ProPedal feature should be reserved for extended fire road climbs or long stretches of smooth singletrack.

We tried the Bontrager Jones XR tire backwards on the rear wheel. This additional scoop was appreciated on hardpack terrain that was covered with loose rocks or sand. The Fuel EX 9.9 is a remarkable-climbing mountain bike, but on more than one occasion we were scratching our heads as to why the tallest rear cassette was a 32-tooth instead of a 34-tooth.

The Fox RP24 fork has a "tunable" ProPedal platform feature that is unique to Trek and Fisher bikes. This adjustment is basically four preset detents applied to the previous lockout/blow-off feature. When climbing in the saddle, we experienced very little fork movement and opted to keep the suspension open on nearly every ride.

Descending: As impressive as the Fuel EX 9.9 is on the uphills, it's equally striking on the descents. Our best descending performance came when we ran the Fox RP24 fork and RP23 shock wide open and rebound a tad faster than normal. The Fuel's 69 degree head angle seems like it would be on the twitchy side, but it navigated steep, rutted terrain with ease. The rear end of the EX 9.9 tracks very well when entering whooped out sections of trail and makes you wonder if it's just being modest about its 4.7 inches of rear wheel travel.
Although impressed with the Fuel's descending capability, we would have been able to hang it out even more with a slightly wider handlebar.

Braking: Trek is hanging their hat on the Active Braking Pivot, and for good reason. The ABP truly allows the suspension to remain active when braking forces are applied, and this allows you to brake more effectively and maintain better traction on rough terrain. Although the ABP is working at slower speeds, it's when you're pinning it through flowing, rock-strewn singletrack that the ABP shows what it's made of. When you pull in the Avid Juicy Ultimate brake lever, the seven-inch front rotor does a great job of keeping speed in check while the rear end remains in contact with the ground.

 

TRICKS, UPGRADES OR TIPS?
As with any suspension setting, the sag is the key to optimizing your riding experience. Be sure to consult the recommended air pressure chart found in the Fuel's manual or online. You can fine-tune the shock's sag with the Fuel's removable sag measuring device sold with the bike.

Throughout our test of the Fuel EX 9.9, we couldn't help but wonder how much better this remarkable package would be if it were equipped with one of Fox's Float forks with their 15QR thru-axle.

The Bontrager Rhythm wheels are tubeless ready, and we recommend going that route right away. We flatted the Jones XR tires more than usual on our cross-country test trails. The Fuel includes valve stems so the wheels can be run tubeless. Be sure to follow up with the dealer, and make sure the valve stems come home with you.

Our only real beef with the Fuel EX 9.9 is the 11-32 rear cassette. A bike this versatile would benefit greatly from an 11-34 cassette. Thankfully, that's an easy fix. Oh, did we already mention we'd prefer a wider handlebar?

TREK FUEL EX 9.9 
Price         $7149
Country of origin        Taiwan
Weight         25.5 pounds
Website Trek Bikes.
Frame tested         17.5"
Bottom bracket height         13.3"
Chainstay length         16.9"
Top tube length         23.2"
Head angle         69°
Seat angle         72.5°
Standover height         29"
Wheelbase         43.5"
Suspension travel (front)        4.7"
Suspension travel (rear)         4.7"
Frame material  Carbon fiber
Fork                 Fox Float RP24
Shock         Fox Float RP23
Rims                 Bontrager Rhythm Pro
Tires         Bontrager Jones XR (2.25")
Hub                 Bontrager Rhythm
Brakes         Avid Juicy Ultimate
Crankset         Shimano XTR
Shifters         SRAM X.0
Handlebar         Bontrager Race XXX Lite (25" wide)
Front derailleur         Shimano XTR
Rear derailleur         SRAM X.0
Chainrings         Shimano XTR (44/32/22)
Cassette        Shimano XTR (11-32)
Pedals         None  (weighed with Shimano XTR)