SQUIRREL_13133715
The S-Works Stumpjumper 15 costs a jaw-dropping £10,000 / $12,000 / €13,000 and, unsurprisingly, sits atop the recently refreshed Stumpjumper line-up.
Specialized overhauled the Stumpjumper, its longstanding full-suspension trail bike, for 2025, ditching the more radical, progressive EVO version in the process.
That’s largely because the new Stumpjumper 15 has been designed to be more capable than ever, with a bump in rear-wheel travel, longer, slacker geometry and plenty of adjustment to ensure it can be adapted to rider taste and terrain alike.
And let’s not forget the new Fox shock, featuring Specialized’s GENIE technology, which helps to create a plush, more comfortable ride that’s highly tunable.
It’s clear, once you hit the trail, that the new S-Works Stumpjumper 15 outshines its predecessor in myriad ways. And that’s not to say the old bike was bad – it really wasn’t, but this bike delivers when it comes to many of those promises – and can be pushed harder and handle more.
There’s no shortage of pep in its step, making it easy to flick around and play about on the trail. However, when things get seriously technical and challenging, this latest iteration feels stable, controlled and confident.
At £10,000, though, the S-Works model costs a serious amount of cash. And while there’s no denying the S-Works Stumpjumper offers an incredible ride, it’s hard to justify the extra spend over the Pro model, which rides just as well but costs a chunk of cash less.
Specialized S-Works Stumpjumper 15 frame and suspension details
Just like all the other Stumpjumper 15 frames currently on offer, the S-Works bike is made from Specialized’s FACT 11m carbon fibre.
This includes both front and rear triangles and, in the case of this top-end bike, the rocker link – something no other bike in the line-up is treated to.
At the rear, travel has been bumped up to 145mm (from 130mm on the standard Stumpjumper). It continues to be dished out using Specialized's tried-and-trusted FSR Horst-Link suspension platform, despite the fact that Specialized explored various other suspension layouts during the Stumpy’s design process.
The changes don’t end there, though. The asymmetrical sidearm is gone in a bid to improve how the front triangle is packaged, and enables Specialized to ensure better seatpost insertion as well as more room for a water bottle.
The bottom bracket is threaded and uses SRAM’s Universal Derailleur Hanger (UDH). This should make finding replacements easier (as long as you’re not running SRAM’s Transmission gearing, as seen here, because it simply uses the space of the hanger, not the hanger itself). The cabling is all internal – thankfully not through the headset.
However, it’s worth noting that the carbon frame only has routing for wireless drivetrains, so don’t expect to replace the rear derailleur with a cable-actuated number should you destroy it.
And let’s not forget the updated SWAT 4.0 down tube storage, which is now easier to access and better sealed. Inside, you’ll find a neoprene pouch to stash spares and tools to prevent them from rattling around while you ride.
Specialized S-Works Stumpjumper 15 geometry details
Despite the Stumpjumper EVO no longer existing, the new bike has adopted much of the geometry and adjustment.
There are three angled headset cups to choose from (each altering the head angle by 1 degree), plus you can tweak the bottom bracket height (by 7mm) via the flip chip in the chainstay pivots.
In its lowest and slackest setting, there’s scope to kick the head angle out to a downhill-bike-like 63 degrees – not something you’ll commonly see on many do-it-all trail bikes, especially from big, mainstream brands such as Specialized.
I measured the size S3 test bike to have a head angle of 64.2 degrees in the middle setting and a seat angle of 78.3 degrees with the saddle set to my preferred pedalling height.
Reach is a reasonable 450mm, while the chainstay measures 435mm and the bottom bracket sits 334mm off the floor.
Chainstay lengths grow across the sizes, starting at 430 on the S1 and maxing out at 445mm on the S6.
While S3-S6 size bikes come with 29in wheels from the get-go, Specialized sells an aftermarket link that enables you to fit a smaller rear wheel if that’s more your thing.
The shock link required will set you back £110 (plus you’ll need to factor a smaller rear wheel into the equation).
Sizes S1-S2, however, come with a smaller 27.5in rear wheel as standard.
Specialized S-Works Stumpjumper 15 specification
At the heart of the new S-Works Stumpjumper 15 is the Fox Factory Float shock with Specialized GENIE technology.
What is this technology, I hear you ask? Well, in short, the new shock contains two, rather than one, positive air chambers (along with a negative).
The two positive chambers (housed inside the extra-large shock sleeve and eyelet of the shock) are connected to boost overall air volume and create a flatter spring curve in a bid to make the first 70 per cent of travel feel more like a coil shock.
As the bike progresses into the final 30 per cent of its 145mm of travel, the ‘GENIE band’ inside the shock slides over and blanks off the ports to the outer air chamber (the sleeve). This effectively reduces the overall air volume and ups the level of force required to access the final part of the travel, making bottoming the shock out harder.
Specialized supplies its own spacers for each of the positive air chambers, claiming they can be tuned independently of one another.
To complement the Factory-spec GENIE shock, up-front you’ll find a top-end Fox 36 fork with GRIP X2 damper – although this bike uses the older GRIP2 and 150mm of travel.
SRAM provides its XX SL Eagle Transmission and Maven Ultimate brakes (with big 200mm rotors), along with a RockShox Reverb AXS wireless dropper post.
Specialized’s Butcher and Eliminator tyres (both in GRID Trail casings) wrap the new Roval Traverse SL II carbon rims, which have been totally redesigned to provide more comfort and better puncture resistance.
The total weight of the S-Works Stumpjumper 15 on test was 13.58kg without pedals.
Specialized S-Works Stumpjumper 15 ride impressions
Alongside spending two days riding the Stumpjumper 15 Pro in Canada, I’ve been able to put the S-Works model through its paces here in the UK.
To do so, I rode on a wide variety of trails, ranging from tame trail-centre flow all the way through to steep, rough and rocky enduro-style trails.
Specialized S-Works Stumpjumper 15 setup
Having already ridden the Pro version of this bike and experimented with shock setup, I knew the stock setting suited me well.
As standard, that means the air sleeve contains a single spacer (out of the four possible), while the eyelet houses the 0.2in.
Set at 140psi, in full riding kit (weighing around 68kg), I was getting 30.9 per cent sag.
In the fork, I was running 69psi, 12 clicks of low-speed compression damping (from closed), no high-speed compression damping and no rebound damping, plus two volume spacers.
It was a shame the fork used the older GRIP2 damper (this was down to the bike being pre-production) rather than the GRIP X2. Having ridden the latter elsewhere, it’s smoother and better suited to lighter riders.
Specialized S-Works Stumpjumper 15 climbing performance
When I first sat on the Stumpy, I was concerned the rear end felt a touch too soft and that it wouldn’t be particularly sprightly uphill.
Thankfully, the relatively low weight, fast-rolling rear tyre and some adjustments to the anti-squat levels (there’s more anti-squat on this bike compared to its predecessor, but less than the EVO) mean when you do get cranking, the Stumpjumper 15 isn’t afraid to work against the gradient.
In fact, it’ll surge forward with each pedal stroke through its short 165mm cranks if you want to give it some oomph.
The back end stays pretty calm while seated, moving only slightly as each crank revolution shifts your weight around.
Specialized’s goal of creating a plush, comfortable initial part of the travel pays dividends when snaking your way up root-riddled inclines. Here, the rear wheel can track fluidly in and out of the divots in the trail as and when it needs to, keeping the Eliminator rear tyre gripping as you make your way up the hill.
Thanks to the steeper seat tube angle, I felt quite upright and over the bottom bracket when climbing, which worked well for me. It’s not so steep that it pushes you too far forwards, though, which means on flatter sections of trail there isn’t too much weight concentrated through your hands and wrists.
Specialized S-Works Stumpjumper 15 descending performance
Point it back down the hill and it’ll deliver a similar level of eagerness.
Although it’s nimble, and easy to pick up and place just about wherever on the trail you want it, there’s still a reassuring air of calm when things get a little rowdier.
Don’t get me wrong, though, the lighter, fast-rolling tyres and low overall weight don’t give you the same planted feel of a heavier enduro bike, meaning there’s a little more fidgeting around when you barrel into a chunky rock section.
However, there’s no getting away from how encouraging the proportions are and the suspension feel is, enabling you to ride just as hard as on a longer-travel enduro rig, even if you're skirting closer to the edge of control in the process.
The slack front end and balanced geometry help to create a confident stance on the bike and enable you to attack the trail when you need to. And here, in the stock setup, you’d be fooled into thinking there’s more travel on tap, because you can push it so hard.
There’s enough comfort and cushioning to prevent you from feeling battered on longer downhill runs, but still ample support available when you need to eke out more speed by pumping through trail undulations.
As and when you start sliding into jagged catch berms and skimming over bulbous root spreads, it’s the rear tyre's survival that makes you tense up a little.
While it’s a great option for general trail riding, it can flex and squirm in high-load turns and requires additional pressure to help it hold its shape, which can feel sketchy as soon as the trails get damp.
Switch to a tougher casing and the Stumpy 15, although very capable as it is, would be even better.
But of course, not everyone wants to ride like I do, which is why the Stumpjumper 15’s versatility is so impressive.
Should you want to add more pep, cramming more spacers into the shock’s outer sleeve makes it feel more like the Stumpy of old, delivering even more support and feedback, enabling you to eke every ounce of speed out of a trail if you’re happy pumping the bike through every undulation.
When you are faced with a series of braking bumps or rocky outcrops, though, in this setup, comfort certainly takes a backseat. More feedback is passed through the bike to the rider’s hands and feet.
What’s smart here, though, is it’s easy to tweak and tune the bike to suit your riding preference or the terrain you're on without too much fuss, highlighting what a good all-rounder this bike is.
Even if the idea of flip chips and shock tuning doesn’t appeal, in its stock setting, this is a trail bike that’s ridiculously fun to ride and far more capable than the 145mm of rear-wheel travel might have you believe.
This S-Works version is seriously pricey, though. Having also ridden the Stumpjumper Pro 15, I’d argue the difference in performance is tough to pick out.
While the Pro model forgoes the wireless dropper and gets (very slightly) downgraded brakes and gearing, it rides just as well as this top-end bike, but costs a significant amount less (£7,500).
It’s still expensive, but if you’re into the idea of getting a high-end, performance trail bike, you won't be disappointed with the Pro version – which I’d have scored higher than the S-Works model due to the similar levels of performance but big price difference.
How does the Specialized S-Works Stumpjumper 15 compare to the YT Jeffsy Core 5?
Having spent a decent amount of time aboard the much cheaper YT Jeffsy Core 5 (£5,999), the S-Works Stumpjumper 15, although more expensive, feels smoother in rough terrain.
Both bikes climb well, although the Stumpy has the edge in terms of sprightliness, and feels a little easier to chuck around – but we’re talking small differences.
While the Jeffsy is a touch longer, the slacker head angle of the Stumpy ensures there’s no real loss in terms of high-speed stability, with both bikes feeling steadfast enough to tackle some seriously tough trails – more so than you’d expect with 145mm of travel at the rear.
When it comes to pricing, maybe this isn’t the fairest comparison, but the Jeffsy Core 5 is the top-end offering from YT. It costs a chunk less due to the direct-to-consumer model YT uses, while the Stumpy is sold through shops.
It’s impressive to see a full-carbon frame, Fox Factory-level suspension and SRAM’s wireless GX Eagle AXS Transmission gearing on the YT.
The Stumpy’s spec trumps it somewhat, with a higher-spec drivetrain, new carbon Roval wheels and the RockShox Reverb AXS post – as it should for an additional £4,000.
Is that extra cash worth it for the jump in performance? Possibly not. But, as I’ve already mentioned, the Pro model of the Stumpjumper represents better value with close to if not the same level of performance – and that’d be my pick of the bunch if I had that sort of cash.
Specialized S-Works Stumpjumper 15 bottom line
The new S-Works Stumpjumper 15 is a seriously capable, fun bike to ride. It’s a plus that it’s so tunable and versatile, making it a real jack of all trades and calling into question how many bikes you might need.
In this top-end guise, it’s hard to find fault with the spec, aside from maybe the rear tyre, but the jump in price from the Pro version is what gets me.
I’d say go for that one if you want a bike as good as this top-tier model while saving yourself some cash in the process.
SQUIRREL_13133715
Product
| Brand | specialized |
| Price | 19500.00 AUD,13000.00 EUR,10000.00 GBP,12000.00 USD |
| Weight | 13.5800, KILOGRAM (S3) - without pedals |
Features
| Fork | Fox Factory 36, 150mm travel |
| br_stem | Deity 35, 35mm |
| br_chain | SRAM XX SL Eagle Transmission Flat Top |
| br_frame | FACT 11m carbon, with carbon link, 145mm travel |
| Tyres | Specialized Butcher Gripton T9 Grid Trail 29x2.3in (fr) / Specialized Eliminator Gripton T7 Grid Trail 29x2.3in (r) tyres |
| br_brakes | SRAM Maven Ultimate (200mm rotors) |
| br_cranks | SRAM XX SL Eagle Transmission |
| br_saddle | Specialized Power Pro Mirror Ti |
| br_wheels | Roval Traverse SL II carbon rims on DT Swiss 240 hubs |
| br_shifter | SRAM XX SL Eagle Transmission |
| br_cassette | SRAM XX SL Eagle Transmission |
| br_seatpost | RockShox Reverb AXS, 170mm |
| br_gripsTape | Deity Lockjaw |
| br_handlebar | Roval Traverse SL Carbon, 800mm |
| br_rearShock | Fox Factory Float with Specialized GENIE technology |
| br_availableSizes | S1, S2, S3, S4, S5, S6 |
| br_rearDerailleur | SRAM XX SL Eagle Transmission |
