Specialized Stumpjumper Evo 15 Alloy 2026

Stumpjumper 15 Alloy is here to obliterate every trade-off in the trail game. Devour bumps like a big bike? Check. Short-travel control, playfulness, and efficiency? Double check. How about a heaping helping of personalization to make it perfect for the only rider who really matters—you?  Check, check, check.

KINEMATICS PERFECTED: As the quintessential trail bike, Stumpjumper 15 Alloy balances efficiency and optimal bump force management. For the anti-squat on Stumpjumper 15 Alloy, we struck a balance between the previous Stumpjumper and Stumpjumper EVO, as both had excellent pedaling characteristics.

HONED GEOMETRY: This bike’s geometry delivers big bike capability when you need it, a nimble feel in tight sections, and lively, efficient climbing manners. The generous cockpit centers you on the bike, optimizing traction and corner control. The low bottom bracket, slack head tube angle, and optimized fork offset keep things stable in the rough.

RIDE YOUR WAY: The Stumpjumper 15 Alloy seamlessly integrates benchmark geo adjustability, making it the most personalizable trail bike ever. Six distinct geometry settings allow you to hone performance for any style and any terrain. The head angle and bottom bracket can be fine-tuned for stability or clearance.

FORM FOLLOWS FUN: We can make a frame as stiff as we want, but there’s such a thing as too stiff. To be one with the bike requires engineered compliance in the frame. We engineered the M5 Alloy chassis—front end, rear end, and the link between them—as a single unit that hits the stiffness target we established for trail riding.

WHEEL SIZE: All coil-sprung models come with mixed wheels.

WHEEL CHOICE: With our aftermarket link shock links, you can choose between big wheels front and rear or mix things up with a 27.5” rear for a more responsive and playful ride. No matter what you choose, geometry is unaffected.

CARRY IT ALL: SWAT on Stumpjumper 15 elevates downtube storage, an innovation we pioneered.

MORE RELENTLESS THAN YOU: Our full-suspension bikes are built to be relentless, designed to endure years of hard riding, and backed by the best support and programs to keep you on the trail. Our unbeatable lifetime, no-questions-asked replacement suspension pivot bearings to the original owner is just one way we've got you covered.

• All-new M5 alloy frame with SWAT door integration
• Ride Dynamics tuned X-Fusion 02 Pro RL shock with adjustable rebound and lockout
• RockShox Psylo Silver fork with Motion Control Damper
• Reliable Shimano MT-420 4-piston brakes
• 12-speed Shimano Deore drivetrain
• Lifetime replacement of suspension pivot bearings to the original owner

Frameset

Frame

M5 alloy chassis and rear-end, Trail Geometry, SWAT™ Door
integration, head tube angle adjustment, threaded BB, internal cable routing,
12x148mm dropouts, sealed cartridge bearing pivots, SRAM UDH compatible, 145mm
of travel

SWAT

Seat Binder

Alloy, 38.6mm

Suspension

Fork

RockShox, Psylo Silver, Motion Control Damper, 15x110 axle,
44mm offset, S1:150mm of travel, S2-S6:160mm of travel

Rear Shock

SRAM RS DLX SEL 210X55 XL4S0 R55C30 SS9 C C2

Brakes

Front Brake

SRAM DB6, 4-piston caliper, hydraulic disc

Rear Brake

SRAM DB6, 4-piston caliper, hydraulic disc

Drivetrain

Bottom Bracket

SRAM DUB Threaded Wide

Rear Derailleur

SRAM NX Eagle, 12-speed

Chain

SRAM NX Eagle, 12-speed

Cassette

SRAM NX Eagle, 12-speed, 11-50t

Crankset

SRAM NX Eagle, DUB, S1-S3:165mm, S4-S6: 170mm, 55mm
Chainline, 32T

Shift Levers

SRAM NX Eagle, trigger, 12-speed

Wheels & tires

Front Tire

Butcher, GRID TRAIL casing, Gripton T9 compound, 29X2.4

Rear Tire

Eliminator, GRID TRAIL casing, GRIPTON® T7 compound, TLR,
S1-S2: 27.5x2.4, S3- S6: 29x2.4"

Rims

Specialized Alloy, Tubeless Ready, 29mm internal width, 28h

Front Hub

Specialized alloy front hub disc, sealed cartridge bearings,
6-bolt, 15x110mm thru-axle, 28h

Rear Hub

Specialized alloy rear hub disc, sealed cartridge bearings,
6-Bolt, 12X148mm thru-axle, 28H, HD Steel Fhb

Spokes

Stainless, 14g

Inner Tubes

Standard, Presta Valve

Cockpit

Stem

Alloy Trail Stem, 35mm bar bore

Saddle

Body Geometry Bridge Saddle, steel rails, S1-S2:155mm,
S3-S6:143mm

Grips

Specialized Trail Grips

Handlebars

Specialized, 6000 series alloy, 6-degree upsweep, 8-degree
backsweep. S1-S2: 780 width, 20mm rise: S3-S6: 800 width, 50mm rise

SeatPost

TranzX dropper, 34.9mm, S1: 125mm, S2: 150mm, S3: 175mm.
S4-S6: 200mm

Product details

Product ID

291350

Specialized Stumpjumper 15 Alloy Size Guide

The Stumpjumper 15 Alloy uses Specialized’s S-Sizing system. Instead of choosing a frame from height alone, S-Sizing allows many riders to choose between two sizes depending on whether they prefer a more agile bike or greater stability at speed.

Rider HeightRecommended SizeTraditional EquivalentWheel Setup150–160cmS1XSMixed 29"/27.5"157–173cmS2SmallMixed 29"/27.5"165–180cmS3Medium29-inch173–188cmS4Large29-inch178–193cmS5XL29-inch188–203cmS6XXL29-inch

How Specialized S-Sizing Works

The height ranges intentionally overlap. This gives many riders the option of choosing between two frame sizes based on their proportions, local terrain and preferred handling.

As a general starting point:

• S1 is similar to a traditional Extra Small
• S2 is similar to a traditional Small
• S3 is similar to a traditional Medium
• S4 is similar to a traditional Large
• S5 is similar to a traditional Extra Large
• S6 is similar to a traditional Extra Extra Large

Choose the Smaller Size If You Want:

• Quicker and more responsive handling
• A bike that is easier to move around on
• More confidence through tight corners
• A more playful feel on jumps and technical sections
• A shorter and more compact riding position

Choose the Larger Size If You Want:

• More stability at speed
• A roomier riding position
• Greater confidence through rough or steep terrain
• A longer wheelbase for high-speed descending
• More space for riders with longer arms or torsos

What If You Are Between Sizes?

If you sit within the overlap between two sizes, consider your body proportions as well as your riding style.

Riders with a longer torso or arms may feel more comfortable on the larger size. Riders with shorter arms, a shorter torso or a preference for agile handling may be better suited to the smaller option.

For example, a 178cm rider could potentially choose an S3, S4 or S5:

• S3 will feel compact and manoeuvrable
• S4 will provide the most balanced all-round fit
• S5 will feel longer and more stable at speed

Most riders should begin with the middle or traditionally equivalent size unless they have a clear preference for a more agile or more stable bike.

Wheel Size and Frame Size

The S1 and S2 use a mixed-wheel setup, with a 29-inch front wheel and 27.5-inch rear wheel. This provides the rollover ability of a larger front wheel while keeping the rear of the bike compact and easy to manoeuvre.

Sizes S3 through S6 use 29-inch wheels front and rear for stability, momentum and smoother performance over rough ground.

Standover Height

SizeStandover HeightS1738mmS2751mmS3745mmS4745mmS5745mmS6751mm

Standover height is useful, but it should not be used as the only measurement when choosing a Stumpjumper. Reach, arm length, riding position and handling preference are equally important.

Need Help Choosing Your Stumpjumper Size?

Contact the Chain Reaction team with your height, inside-leg measurement and current bike size. Let us know whether you prefer a more agile bike or greater stability, and we can help narrow down the best S-Size before you order.

Every Stumpjumper purchased from Chain Reaction is professionally assembled and safety checked, with expert suspension and setup advice available.

This guide applies to the 2026 Specialized Stumpjumper 15 Alloy range. It is intended as a starting point, as rider proportions, terrain and handling preferences can affect the best size.