Specialized says the new v15 Stumpjumper is the best yet, because math and science 🧪

The Specialized Stumpjumper 15 gets a new look, updated geometry, and new shock tech that moves closer to the Stumpy EVO.
Photos provided by Specialized.

The latest and greatest Specialized Stumpjumper is out today, and for those keeping track, this is the 15th iteration of the iconic and bestselling trail bike. The bike sports an all-new form factor, updated geometry, and new air shock tech that promises to deliver coil-like benefits. But mostly, it seems, Specialized just wants to geek out on the math and dazzle us with graphs.

New look

Let’s start with the bike’s new streamlined look. Specialized barely mentions form factor updates in the press materials they provided ahead of the launch, and full-on photos of the complete bike are scant. The Stumpjumper 15 ditches the asymmetrical front triangle bridge first introduced in 2018. There’s still an abrupt kink in the seat tube below the pivot and the bike maintains its overall balanced-looking trail stance.

In many ways, the latest Stumpjumper appears to move closer to the Stumpjumper EVO, starting with an increase in suspension travel to 150/145140mm front and rear, up from 140/130mm. (Smaller sizes feature a 140mm fork.) That’s still less travel than the Stumpjumper EVO, though only by 5mm.

Stumpjumper 15 geometry

With an eccentric upper headset and Horst link flip chip, the Specialized Stumpjumper 15 offers six different geometry combinations. The head tube angle can be set to 63°, 64.5° (default), or 65.5°, while the bottom bracket can be set at 337mm (default) or 330mm. The default 64.5° head tube angle matches the Stumpy EVO, and is half a degree slacker than the previous Stumpjumper. The reach hasn’t really changed across the size run, and the chainstays are a smidge shorter but basically unchanged.

STACK608 mm618 mm627 mm640 mm654 mm667 mm
REACH400 mm425 mm450 mm475 mm500 mm530 mm
HEAD TUBE LENGTH95 mm100 mm110 mm125 mm140 mm155 mm
HEAD TUBE ANGLE64.5 °64.5 °64.5 °64.5 °64.5 °64.5 °
BB HEIGHT334 mm337 mm337 mm337 mm337 mm337 mm
BB DROP41 mm38 mm38 mm38 mm38 mm38 mm
TRAIL129 mm130 mm130 mm130 mm130 mm130 mm
FORK LENGTH551 mm561 mm561 mm561 mm561 mm561 mm
FORK OFFSET44 mm44 mm44 mm44 mm44 mm44 mm
FRONT CENTER720 mm751 mm780 mm812 mm843 mm879 mm
CHAINSTAY LENGTH430 mm432 mm435 mm435 mm445 mm445 mm
WHEELBASE1,149 mm1,181 mm1,213 mm1,244 mm1,285 mm1,322 mm
TOP TUBE LENGTH , HORIZONTAL541 mm573 mm595 mm624 mm647 mm677 mm
BIKE STANDOVER HEIGHT738 mm751 mm745 mm745 mm745 mm751mm
SEAT TUBE LENGTH385 mm385 mm405 mm425 mm445 mm465 mm
SEAT TUBE ANGLE77.0 °76.5 °77.0 °76.9 °77.3 °77.6 °
SEAT POST MAX INSERTION245 mm245 mm255 mm255 mm285 mm285 mm
SEAT POST MIN INSERTION80 mm80 mm80 mm80 mm80 mm80 mm
Specialized Stumpjumper 15 geometry with the middle head tube angle and high bottom bracket setting.

Specialized is really leaning into their free-form sizing system, suggesting, for example, that a 5’8″ tall rider might choose an S2, S3, or S4, depending on their riding style.

The GENIE is out of the bottle

In development for three years, the Stumpjumper 15 features all-new shock tech Specialized is calling GENIE. Presumably, the brand partnered with Fox to implement a shock that seeks to combine some of the advantages of a coil shock with a traditional air shock. Specialized produced a 13-page white paper (embedded below) to show that GENIE gives the Stumpjumper 15 “57% better traction” than the Stumpy EVO and it “handles 16.3% better” than the EVO, too. Oh, and GENIE delivers “39% fewer severe bottom out events compared to a standard air spring.” How many severe bottom out events should riders expect on a normal ride? We’re not sure.

While we don’t have any reason to doubt that Specialized has done its homework on this one, the data is not easy to understand. The SparkNotes version, as best we can tell, is that GENIE is a two-stage shock with connected but separate positive air chambers. The middle and end strokes are independently tunable via tokens, allowing riders to optimize performance for their riding style. GENIE is said to offer excellent small bump compliance that’s supple off the top of the stroke, just like a coil shock.

Specialized Stumpjumper 15 builds

At launch, buyers can choose from at least five different builds, including the lowest-priced Comp build which features the all-new SRAM S-1000 Eagle Transmission drivetrain. Mixed wheel builds are available for sizes S1 and S2, while S3-S6 sizes appear to come with matched 29er wheels. All of the builds feature a Fact 11 carbon chassis (which we take to mean the front triangle) and rear triangle. The S-Works build upgrades the linkage to carbon as well, and an S-Works frameset will be available for purchase in addition to the full build. Alloy Stumpumper 15 frames are not available at launch.

It’s also interesting to note that one of the builds, the Stumpjumper Öhlins Coil, doesn’t feature flagship GENIE suspension tech.

All Stumpjumper 15 frames offer “lifetime replacement of suspension pivot bearings to the original owner.”

Weights, pricing, and availability for the Specialized Stumpjumper 15 were not available as of press time. We will update this article as more information becomes available.