The Stumpjumper 15 Alloy is designed to eliminate trade-offs in trail riding. It delivers the bump-absorbing capability of a larger travel bike while maintaining short-travel control, playfulness, and climbing efficiency. The bike offers extensive personalization options to tailor the ride to individual preferences. The centerpiece of this frameset is GENIE, Specialized's patent-pending air spring technology. GENIE combines the linear spring rate of a coil spring through the bump zone with the progressive spring rate of an air spring at the end of the stroke. This dual-stage design provides maximum grip and traction comparable to a coil spring, superior bottom-out prevention compared to standard air springs, and the ability to independently tune mid-stroke and end-stroke support. Performance testing demonstrates that GENIE delivers measurably better traction than the previous Stumpjumper EVO. The shock manages bump forces 16.3% better than traditional air-sprung shocks, allowing the 145mm rear travel Stumpjumper 15 Alloy to absorb impacts comparable to longer-travel bikes. Field testing shows 57% better traction than standard air-sprung shocks and 39% fewer bottom-outs due to the pronounced rising rate in the final 30% of the stroke. The geometry is engineered for versatility, delivering big bike capability on rough terrain while maintaining nimbleness in tight sections and efficient climbing characteristics. The generous cockpit centers the rider for optimized traction and corner control. A low bottom bracket, slack head tube angle, and optimized fork offset provide stability in rough conditions. The frameset features six distinct geometry settings for personalization, allowing fine-tuning of head angle and bottom bracket height for stability or clearance. Wheel configuration is also adjustable-riders can run 29" wheels front and rear or mix a 27.5" rear for a more responsive and playful ride without affecting geometry. The frame integrates SWAT internal downtube storage and features an M5 alloy construction with sealed cartridge bearing pivots. GENIE Grants Every Trail Rider's Wishes This game-changing, patent-pending air spring technology that we invented grants every trail rider three wishes: feel and control of a coil spring, better bottom-out prevention than a standard air spring, and a tunable "platform" for a playful feel. What's Inside GENIE? Check out how GENIE combines the control-enhancing linear spring rate of a coil spring through the "bump zone" with the progressive spring rate of an air spring at the end of the stroke to reduce bottom-outs. It's the best of both worlds - coil and air - with extra tuneability. Say goodbye to compromises and hello to the future of riding. Unlock Your Ride with Tunable Geo Stumpjumper 15 boasts the planet's most capable trail geometry. With six-way adjustability, tailor your ride to perfectly match your style and terrain. Explore our interactive Geo Finder to pinpoint your ideal setting. Eats Bumps Like an Enduro GENIE shock technology gives the Stumpy 15 16.3% better bump performance than 'Bike of the Year' Stumpjumper EVO. It literally uses more travel for the same size bump, thanks to its flatter spring curve in the first 70% of travel. 57% Better Traction GENIE delivers 57% less traction loss time than a standard air-sprung shock because GENIE technology gives you supple, coil-like performance, which keeps the wheel in contact with the ground a greater percent of the time than a typical air spring would. Bye, Bye, Bottom Outs Send it with confidence knowing that in field testing GENIE eliminated 39% of severe bottom out events compared to a standard FOX Float air spring. Meet the Creators Many (dirty) hands, one (awesome) bike. Over 50 R&D teammates, each and every one a trail rider, worked for more than three years to make Stumpjumper 15 One Bike to Rule All Trails. All You Need to Know Don't like to read? No problem. Check out this short video and learn of all the highlights about the Stumpjumper 15.