Trail bikes can't usually 'shred the gnarly stuff' and 'climb with your XC buddies' but we're confident in saying that the Stumpjumper Expert ST 29 is totally capable of both. It combines precise handling perfect suspension kinematics and a complete abandon of proprietary nonsense with a slightly steeper geometry less travel (130mm front/120mm rear) and 29-inch wheels to make it a true 'do-it-all' trail bike.
Our design goal for the new Stumpjumper was simple - build the ultimate trail bike one that feels telepathic. And it turns out that this feeling all comes down to stiffness. Think of it this way: when the frame's telling your hands one thing and your feet another your brain gets confused with the imbalance and the bike feels unstable. In order to fix this we had to get to work on dialing-in the materials shapes and the layout.
We started by creating our own mountain-specific stiffness test and then we looked at the layout with Finite Element Analysis (FEA) to see where we could get the biggest stiffness improvements. This led to a big discovery: The Large and X-Large frames needed more front-end stiffness while the Smalls and Mediums were just fine. We were able to create a frame design that was 20% more efficient. And in the end this proved to be one of the lightest trail frames on the market today.
When designing the frame with the stiffness targets being a main goal we developed a radical new sidearm design. The front-end and rear-end are connected at three points and the sidearm helps keep all these points super stiff and connected all while taking about 100 grams out of the rear-end. More explicitly this minimizes frame flex when the rear suspension is active.
We continued down the suspension path with a custom Rx Trail Tune on both the fork and rear shock. Suspension performance is highly dependent on frame wheel and rider size so we use our Rx Tune to get each bike to land in the middle of the adjustment spectrum and this gives you the biggest possible range to fine-tune your ride. Another focal point of the tune was matching the suspension characteristics between wheel sizes - we developed a specific Rx Tune for each platform. So no matter what wheel size you prefer you'll get perfectly linear suspension.
Steps were also taken to make this bike easy to live with. Threaded bottom brackets make a triumphant return and we made room for up to a 3.0' tyre. You're also free to run whatever aftermarket rear shock you want since we're using standard metric shocks. We revamped the SWATâ„¢ box too making it sleeker lighter and with more volume. And customization is furthered with a Flip Chip that lets you to dial-in your Stumpy to your riding style. Switch it from High to Low and it drops your bottom bracket 6mm and slackens the head tube by half-a-degree. Little details also jump out to surprise you like a newly designed ribbed chainstay protector that makes chain slap a thing of the past and nearly silences the drivetrain. Lastly we seriously couldn't make cable routing any easier on carbon models. Full tubes can be found throughout the carbon frame so all you have to do is push the cable and it'll come out the other end. No more lazy loop hidden stashes of magnets pokey spokes or pillows to cry in.
For the build you get a solid components package with a full SRAM GX1 Eagle drivetrain SRAM Guide R disc brakes RockShox Pike RC fork and a Deluxe RT3 rear shock (130/120mm of travel respectively) and Roval Traverse Carbon 29 wheels.
|Frame||FACT 11m, full carbon chassis and rear end, asymmetrical design, 29 Trail Geometry, SWATâ„¢ Door integration, threaded BB, fully enclosed internal cable routing, 12x148mm dropouts, sealed cartridge bearing pivots, replaceable derailleur hanger, 120mm of travel|
|Fork||RockShox Pike RC, DebonAir, rebound / low-speed compression adjust, tapered steerer, 51mm offset, 15mm Maxle Stealth thru-axle, 15x110mm Boostâ„¢, 130mm of travel|
|Rear Derailleur||SRAM GX Eagle, 12-speed|
|Shift Levers||SRAM GX Eagle, trigger, 12-speed|
|Chainset||Truvativ Descendant, aluminum, Boostâ„¢ 148, 170mm crankarm, 24mm spindle: 30T|
|Bottom Bracket||SRAM GXP|
|Chain||SRAM GX Eagle, 12-speed|
|Cassette||SRAM GX Eagle, 12-speed, 10-50t|
|Stem||Specialized Trail, forged alloy, 4-bolt, 5mm rise|
|Handlebars||Specialized Trail, 7050 alloy, 8-degree backsweep, 6-degree upsweep, 27mm rise, 780mm, 31.8mm clamp|
|Front Brake||SRAM Guide R, hydraulic disc, organic pads, Guide S4 4-piston caliper, 200mm|
|Rear Brake||SRAM Guide R, hydraulic disc, organic pads, Guide S4 4-piston caliper, 180mm|
|Rims||Roval Traverse Carbon 29, hookless carbon, 30mm inner width, 28h, tubeless ready, hand-built|
|Front Hub||Specialized, sealed cartridge bearings, 15x110mm spacing, 28h|
|Rear Hub||Specialized, sealed cartridge bearings, 12x148mm thru-axle, 28h|
|Spokes||DT Swiss Industry|
|Tyres||Butcher, GRID Casing, GRIPTON compound, 2Bliss Ready, 29x2.3|
|Saddle||Body Geometry Phenom Comp, Adaptive Edge design, hollow Cr-Mo rails, 143mm|
|Seatpost||Command Post IRcc, 16-position micro-height adjustable, two-bolt head, bottom mount cable routing, remote SRL lever, 34.9mm, S: 130mm, M/L/XL: 160mm of travel|
|Grips /Tape||Specialized Sip Grip, half-waffle, S/M: regular thickness, L/XL: XL thickness|
|Rear Shock||RockShox Deluxe RT3, Rx Trail Tune, rebound & 3-position compression adjust, 190x42.5mm|