The Legend Returns At the height of mountain bike racing, the Top Fuel ruled the podium, and now it's back once again to take the top spot. Fantastically refined by Trek, the Top Fuel 9.9 RSL ensures you are the fastest rider on the trail. As versatile as it is fast, it is an obvious choice for any cross country racer always looking to better their last ride. Key features RE:aktiv XC: the smartest, fastest, most efficient shock ever Boost148/110: stronger wheels, more tyre clearance, shorter stays Race Shop Limited: Pro-level bikes for the most discerning riders Exclusive suspension tech with ABP and Full Floater Features Smart Wheel Size The right wheel size paired with your frame size gives you the perfect combination of responsiveness and control. Mino Link adjustable geometry Fine tune head tube angle by 1/2° and BB height by up to 10mm with the simple turn of a nut. Just flip the link to choose between slack or slacker geometry, without negatively affecting suspension performance. Control Freak cable management The lightest, quietest and most versatile cable management system allows any combination of shift, brake, lockout and dropper post lines to be routed through the frame for clean looks and the ultimate custom set-up. Remote lockout Handlebar-mounted controls let you lock out your suspension on the fly as you switch terrains. OCLV Mountain Carbon Trek's mountain-specific carbon fibre is tougher carbon, with unique materials and lay-up procedures, Trek's advanced engineering, and a higher standard of testing. RE:aktiv XC RE:aktiv XC's race-tuned regressive damping delivers a greater pedalling platform and higher degree of responsiveness without sacrificing plush control. Boost148/110 Wider dropouts (110mm front, 148mm rear) give you the stiffness of a 27.5 wheel with all the benefits of a 29 wheel, and Boost148 at the back lets you run wider tyres and a larger chain ring without affecting q-factor and pedalling efficiency.