Specialized has reinvented the mighty Stumpjumper for 2025

Say hello to the ‘Stumpjumper 15’, the latest generation of the most popular MTB model Specialized has ever made, so it’s arrival is kind of a big deal!

And of course it’s the bike that has been designed to go head-to-head out in the market with offerings such as the Giant Trance and Trance X, the Norco Sight, the Trek Fuel EX and even the SantaCruz Hightown. So, what have Specialized cooked up to do battle in the most competitive category in all of MTB? Let’s dive in and take a look.  

As the name on the packet suggests, the ‘Stumpjumper 15’ is the brand’s 15th  rendition of the model since it was first debuted way back in 1981. Today, Specialized’s approach to creating the ‘ultimate one bike to do it all’ was to jam pack the Stumpy line-up with plenty of key specification options, such as wheel sizes, and then loading each model with a ton of frame adjustment features so that the rider can fine tune the characteristic of the bike to perfectly suit their individual style. 

It’s also interesting to note that Specialized have dropped the ‘Stumpy Evo’ model from their new season line-up. The reason being is that the new Stumpy 15 features a much more ‘party friendly’ geometry package than we’ve seen on previous regular Stumpy generations, so essentially the brand made the decision to blend the Stumpy and the Evo models together to combine a single Stumpy platform. 

Another very interesting take away from reading the Stumpy 15’s press kit is that there are no alloy frame options in the line-up, only carbon. That said, we’d bet good money that at some point Specialized will add alloy bikes into the Stumpy 15 range in order to bring the price point down and in turn make the Stumpy accessible to a wider market.   

Now let’s talk about the bike’s big drawcard: to bring extra ‘wow factor’ to the Stumpy 15 range Specialized teamed up with Fox Factory to develop a unique twin chamber rear shock called GENIE.

This new shock design will exclusively be offered across the Stumpy 15 family and it promises to super change the bike’s handling. Now, it’s probably fair to say that the GENIE shock looks like any other air shock from the outside. However from what we’ve been told the ‘magic’ hides in some special technology hidden inside. What sets it apart is that it has a positive and a negative chamber but forgoes an external reservoir. The special feature of the GENIE is that the positive chamber is divided into an inner and outer air chamber. The inner chamber acts as the main spring, while the outer chamber closes off for the last 30% of the stroke, reducing air volume to increase progression. The chambers are connected by special valves.

The GENIE damper uses the entire volume of the inner and outer air chamber in the first 70% of the travel, which results in a more linear response behaviour, ensuring maximum traction and top sensitivity. When the shock reaches the last 30% of its travel, the piston rod shuts off the valves between the two chambers. This separates the outer air chamber from the inner main chamber, reducing the air volume and making the shock more progressive in the last part of the stroke. This is meant to provide more resistance and prevent harsh bottom-outs. We haven’t actually had a chance to test ride a Stumpy 15 so we can’t confirm how GENIE performs out on the trail, but the theory behind GENIE does sound impressive, eh? 

As part of the bike’s complete redesign there are several key differences between the Stumpy 15’s frame compared to the outgoing Stump range, most notably they’ve decided to ditch the ‘sidearm’ and they’ve redesigned rocker linkage which is now a one-piece design. Ultimately though the bike’s suspension is still a four-bar layout with a yoke driving the shock which now produces 145mm of rear travel. 

In a rather surprising move that risks angering some consumers (ie: Shimano drivetrain fans) their Stumpy 15’s frame doesn’t feature cable routing for a shift cable, meaning that it’s only compatible with electronic drivetrains. Perhaps this is a sign things to come and become more common in the future? For now though this is the only ‘trail bike’ on the market that doesn’t offer rear mech cable routing as standard.    

In terms of wheel size across all Stumpjumper 15 models, of which there are 5 completes being offered down here in Oz, all of them come spec’d as full 29er bikes, however the brand is promoting that riders can choose to convert their Stumpy 15’s to a mullet set-up but they will have to shell out for an aftermarket link kit in order to do so. 

Hopefully we’ll be getting our hands on a Stumpy 15 test bike at some point in the near future so keep an eye out here on our site and across on our YouTube channel. And in the mean time to browse the new Stumpy range for individual spec sheets and geo charts, etc, head on over to specialized.com/au


Travel: 150mm front, 145 mm rear.

Wheel Size: 29” or Mixed 29”/27.5”

Carbon only, no alloy frame options

‘GENIE’ dual chamber rear shock

Frame sizes: S1, S2, S3, S4, S5, S6

Headtube Angle: 63° (Low), 64.5° (Mid), 65.5° (High),

SWAT internal frame storage

Aussie complete pricing starts at $8999