The 2025 Trek Top Fuel 9.9 X0 AXS Gen 4 is a top-tier down-country machine built for riders who demand efficiency on climbs and confidence on descents. Its OCLV Mountain Carbon frame delivers 120mm of rear travel paired with a 130mm fork, striking the perfect balance between XC speed and trail capability. Outfitted with SRAM’s X0 Eagle AXS Transmission, it provides flawless wireless shifting and a wide gear range, while carbon wheels and premium suspension keep weight low and performance high. With progressive geometry, in-frame storage, and integrated features, the Top Fuel 9.9 is a race-ready yet trail-hungry bike for riders chasing speed across technical terrain.