Details
This is Trek's answer to the question: Who makes a world-beating cross-country mountain bike that can handle marathon-length events?
The Top Fuel 9.9 could be the best full-suspension XC racer on the planet. It's absurdly light at less than 25 pounds (!!) when set up tubeless. The main frame and rear suspension arms are all made from Trek's exclusive OCLV Mountain carbon fiber, bringing incredible strength to handle every pedal stroke over rough trails. Every aspect of the main frame has been optimised for high performance without adding pounds. The frame's Straight Shot downtube eliminates plenty of material while enhancing torsional strength. Don't worry, the fork crown won't whack the down tube during a crash, thanks to a clever Knock Block steerer stop at the top of the head tube. Out back, the Active Braking Pivot (or ABP) full suspension geometry isolates braking forces from suspension movement, so every gnarly downhill hairpin won't feel like a major test of your riding talents. Control Freak internal cable routing, a tapered head tube, and downtube-mounted Carbon Armor are examples of the details that make every Trek Top Fuel mountain bike a clear leader in XC racing machines.
The air-adjustable RockShox Pike Ultimate suspension fork helps to tame rock gardens and challenging course features with ease. 120mm of travel soaks up impacts, while a bar-mounted lockout twist-lever shuts off the shock when charging along hardpan and jeep doubletrack. The rear shock is also a RockShox Deluxe Ultimate unit, bringing 115mm of travel and the aforementioned lockout function.
Trek chose SRAM's best off-road drivetrain for the Top Fuel 9.9: 12-speed Eagle AXS. Yes, this is the wireless shifting SRAM drivetrain for mountain bikes. Powered by a rechargeable Li-Ion battery, every shift is perfect. Every. Single. Time. The XX1 AXS rear derailleur can handle hard pedaling loads and poorly-timed shifts with ease. Plus, there's no shift cable or housing to get nasty in messy conditons! Cool, huh? A 10-50T SRAM Eagle rear cassette boasts a massive gearing range for roller-coaster trails and courses. Power delivery is done through a carbon fiber SRAM XX1 Eagle crankset with a 32T single direct-mount chainring.
Bontrager supplies the tubeless-ready OCLV carbon fiber Kovee Pro 30 wheelset. The 30mm-wide internal rim width allows the tire to spread out for better trail contact, enhancing lateral grip and lower rolling resistance. Boost110/148 thru-axle hubs improve lateral rigidity, while a Rapid Drive 108 rear freehub makes pedaling response lightning-quick. With a total wheelset weight of only 1500 grams (without tires or cassette), the Top Fuel 9.9 will leap out of corners and hairpins like a jackrabbit! Bontrager's 29x2.4" XR3 Team Issue tires are also tubeless-ready, bringing bags of grip to any trail surface. SRAM Level Ultimate hydraulic disc brakes boast excellent stopping power in all conditions, rain or shine (or mud).
The Top Fuel 9.9's RockShox Reverb AXS dropper post is just as high-performance as the rest of the bike. It's wireless, using a bar-mounted remote lever for clean installation, and uses the same rechargeable battery as the SRAM XX1 Eagle AXS rear derailleur. A carbon-railed Montrose Pro saddle, Kovee Pro stem, OCLV carbon fiber Line Pro handlebar complete this world-beating off-road racer.
A SRAM eTap AXS battery charger is included with the purchase of this bicycle.
This bicycle can be ordered through Trek's Project One program. Tens of thousands of color and component configurations can be ordered, making the Top Fuel 9.9 AXS uniquely your own. Please call for details.
Electronic drivetrain systems deliver excellent shifting, easy set up, and solid battery life. Here are the highlights of today’s electronic shifting systems:
Shifting Performance
Electronic shifting systems use powerful servomotors to rapidly shift the chain. Because microprocessors and sensors constantly monitor every aspect of the system, they shift with precisely and without chain rub.
Customization
Many major systems have customizable shifting. Some have the ability to add remote shifters for common riding positions, and some even allow you to change the functions of the shifting buttons.
Dependability
Electronic groupsets are responsive and consistent. There are no cables to stretch and wear out, so you get a flawless shift every time. The added bonus is you’ll never have to replace a derailleur cable ever again.

A dropper seatpost allows you to quickly lower and raise your seat to give you an ideal riding position. Dropping your seat creates a lower center of gravity for better control and maneuverability on steep descents, while raising it puts you at normal riding height for efficient pedaling.
Construction can include either hydraulic- or cable-actuated systems and the post’s travel can either be infinitely adjustable or stopped at set intervals, depending on the model.
Dropper seatposts come in standard lengths and diameters and vary by the amount of travel.
Pedals sold separately
Specs
Frame | OCLV Mountain Carbon main frame & stays, tapered head tube, Knock Block, Control Freak internal routing, Carbon Armor, magnesium rocker link, Mino Link, ABP, Boost148, 115mm travel |
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Fork | RockShox Pike Ultimate, DebonAir spring, Charger 2 RC2 damper, tapered steerer, 42mm offset, Boost110, 15mm Maxle Stealth, 120mm travel |
Headset | Knock Block Integrated, sealed cartridge bearing, 1-1/8'' top, 1.5'' bottom |
Rear Shock | RockShox Deluxe Ultimate, TwistLoc remote lockout |
Axles |
Front: 110x15mm Rear: 148x12mm |
Rims/Wheels | Bontrager Kovee Pro 30 carbon, Tubeless Ready |
Hubs | Bontrager 6-bolt alloy |
Spokes | Stainless steel straight-pull |
Tires | Bontrager XR3 Team Issue, Tubeless Ready, Inner Strength sidewall, aramid bead, 120tpi, 29x2.40" |
Crankset | SRAM XX1 Eagle AXS Carbon, DUB, Boost |
Chainrings | 32T alloy ring |
Bottom Bracket | SRAM DUB, 92mm, PressFit |
Chain | SRAM XX1 Eagle, 12 speed |
Rear Derailleur | SRAM XX1 Eagle AXS |
Cassette/Rear Cogs | SRAM XG-1299 Eagle, 10-50T, 12 speed |
Shifters | SRAM Eagle AXS, wireless, 12-speed |
Handlebars | Bontrager Line Pro, OCLV Carbon, 35mm, 15mm rise |
Tape/Grips | SRAM TwistLoc |
Stem | Bontrager Kovee Pro, 35mm, Knock Block, Blendr compatible, 13 degree |
Brake Levers | SRAM Level Ultimate hydraulic disc, carbon fiber levers |
Brakes | SRAM Level Ultimate hydraulic disc, 160mm rotors |
Saddle | Bontrager Arvada, austenite rails, 138mm width |
Seat Post | RockShox Reverb AXS, wireless, 31.6mm |
* Subject to change without notice.