The primary Stumpjumper debuted 43 years in the past in 1981, and that is the 15th full-suspension iteration of the bike. After three years of improvement, Specialised has taken presumably their most confirmed bike and made considerate refinements to make it even higher. The brand new Stumpy is an environment friendly pedaling path bike, however by way of its changes and intelligent suspension tech, it may possibly deal with much more than your common 145mm journey MTB.
Specialised Stumpjumper 15 – Body Options:
The Stumpjumper 15’s entrance and rear triangles are constructed from FACT 11m carbon fiber. One noticeable replace is how there is no such thing as a extra asymmetrical ‘sidearm’ help bridging from the seat mast to the highest tube. Specialised stated they had been very pleased with the earlier design, however realized they may transfer the fabric from the sidearm into the Stumpy 15’s beefed-up shock hyperlink and obtain the identical energy and stiffness with a cleaner look.
Sticking with Specialised’s long-standing FSR suspension linkage, the 2025 Stumpy has been bumped to 145mm of rear journey. All fashions include 150mm forks on body sizes S2-6 and 140mm forks on the smallest S1 measurement. The Ohlins Coil mannequin is one other exception, which has a 160mm fork on all body sizes.
Like many manufacturers lately, Specialised goes with MX wheels on smaller sizes (S1 and S2) and stocking all bigger sizes (S3 – S6) with 29” wheels. Nevertheless, the bigger body sizes are mullet suitable by swapping to aftermarket shock hyperlinks. The hyperlinks maintain the Stumpy’s geometry and suspension traits the identical between both wheel measurement.
One other key addition to the Stumpjumper 15 is its adjustable head tube angle. By swapping the headset cups, you possibly can select between impartial or +/- 1° cups. Between the cups and BB peak flip-chip, the steering angle can range from 65.5° to a really slack 63°.
Fitments and Body Safety:
When you like the brand new Stumpy, I hope you want wi-fi shifting too as a result of there is no such thing as a routing for a derailleur cable on this body! The routing for the brake hose and dropper submit cable is glossy and tidy. Straight entry holes on the top tube maintain the hose/cable from rattling or rubbing on the body.
As for body safety, the Stumpjumper 15 comes with chainstay and seatstay guards plus a mudflap behind the BB to maintain rocks out of your linkage. It additionally will get a decrease down tube protector, and a transparent protecting sticker protecting the underside of the down tube. Specialised additionally consists of Fox’s entrance fender on the Stumpy Professional and S-Works fashions.
Body fitments embrace 148mm Enhance rear axles, BSA 73mm threaded BBs, and SRAM UDH derailleur hangers. Specialised specs a number of dropper submit manufacturers on completely different Stumpy fashions, so take a look at their web site for the journey numbers. The frames settle for 34.9mm seat posts.
SWAT 4.0 Body Storage:
Specialised has redesigned its SWAT storage door and latch system, which now has a clear flush-mounted look. The latch now grabs straight onto the body. If that sounds questionable to you, relaxation assured Specialised extensively examined it to make sure mud, mud, snow, and many others, doesn’t hamper its operation or harm the bike in any respect.
The down tube gives ample area inside for journey necessities. My take a look at bike (S3 body) simply match a big c02 canister, inflator, plug device, spare plugs, a spare battery for the AXS shifter, and a multi-tool, with room for extra. Specialised provides a zippered device bag for in-frame storage.
I used to be comfortable to seek out the S3 body simply accepts a big water bottle, with ample room to entry it.
Genie Rear Shock:
The Stumpjumper 15 includes a new Fox Float X Genie rear shock, which is a patent-pending know-how developed by Specialised. Whereas the Genie shock was developed for this bike, the brand new Stumpjumper can run any rear shock together with coils. That’s partly why Specialised specs one mannequin with Ohlins coil suspension.
Now right here’s what’s particular concerning the Genie shock: It options an outer constructive air chamber and an inside constructive air chamber. They work collectively whilst you journey, because the outer chamber closes off if you hit about 70% journey. This causes the shock to basically shrink its air chamber and create a ramp-up impact to extend bottom-out resistance.
In the course of the preliminary stroke, the Genie’s two air chambers are each open and supply a big quantity of air, providing a flatter spring curve for the primary 70% of the stroke. This ensures delicate, coil-like bump administration all through smaller and mid-sized impacts.
While you attain 70% journey, a sleeve contained in the shock known as the Genie Band slides up and closes off the Genie Air Port holes resulting in the outer air chamber. The air quantity within the shock is diminished to the inside chamber solely, making a extremely progressive spring curve.
Controlling the primary 70% of the stroke, the outer air chamber’s spring price may be adjusted individually from the inside air chamber with as much as 4 clip-on quantity spacers. This permits riders to decide on between most bump sensitivity or a extra supportive journey really feel. Including or eradicating these quantity spacers is a reasonably simple job most riders might deal with and not using a store’s help. The inside air chamber’s bottom-out resistance may be independently tuned with eyelet quantity spacers.
Along with the distinctive elements of the Genie rear shock, it additionally comes outfitted with a two place swap (with a reasonably agency climb mode) and a 3 place open mode adjustment (on all however the Comp mannequin).
Suspension Traits:
Specialised designed the brand new Stumpjumper to capably deal with tough terrain and large impacts, but preserve the poppy journey and environment friendly pedaling of a shorter journey bike. The Stumpy goals to supply sensitivity to small and mid-sized bumps, the power to eat up sq. edged hits, and a bottomless really feel on massive drops.
By the numbers, Specialised says the Stumpjumper 15 gives 16.3% higher bump pressure administration and 57% higher traction than the Stumpjumper EVO (which means 57% much less traction loss time between impacts). As a result of rising price within the final 30% of the Genie shock’s stroke, Specialised studies 39% fewer extreme backside outs than a standard air spring.
The softer preliminary stroke of the Genie shock requires much less pressure to maneuver the rear wheel than the Specialised Enduro or Stumpy EVO. This implies the brand new Stumpy is extra keen to make use of preliminary/mid-travel to suck up impacts and supply a clean journey. The numbers present when the Genie-equipped Stumpy 15 is hit with a 1,080 Newton influence, the bike will use 100mm of journey to soak up it, whereas the Stumpy EVO will use 86mm of journey. This eagerness to make use of its preliminary and mid-stroke helps the Stumpjumper 15 obtain its feeling of getting extra journey than it really does.
In fact, pedaling effectivity is of key significance for a path bike. The Stumpy 15’s anti-squat was tuned to take a seat between the earlier Stumpjumper and Stumpy EVO.
Geometry:
The Stumpjumper 15 will probably be out there in 5 body sizes – S1 to S6. Specialised retains the top tube lengths and standover heights considerably shut throughout the scale vary so riders can select the attain/wheelbase that fits their type greatest. You’ll be able to decide to go shorter for nimbler dealing with, or longer for extra stability.
With the Stumpy’s adjustable headset angle and BB peak flip-chip, there are six completely different geo configurations doable. The swappable headset cups supply a impartial setting or +/– 1°. Mixed with the BB peak chip the Stumpy’s steering angles can range from 63° to 65.5°. That’s a superb vary for a contemporary do-it-all path bike.
The BB is pretty low in both setting at 337mm in Excessive place or 330mm in Low. Transferring from Excessive to Low additionally slacks the bike out by 0.5°.
Attain numbers are up-to-date however not loopy, and given the S sizing scheme, you’re not caught with a sure measurement based mostly in your peak or inseam. At 5’10” I discover myself in the course of the S3 and S4 frames. At 450mm the S3 (which I’m testing) is on the quick facet for me, however at 475mm the S4 can be prolonged. Each, nevertheless, are completely inside purpose for somebody my peak. As a shopper, I’d undoubtedly wish to take a look at journey each earlier than making a call.
Seat masts angles range barely between body sizes, however vary from 76.5° to 77.6° (in impartial/Excessive place). The Stumpy 15 sticks with shorter chainstays throughout the board. Specialised gives three completely different rear finish lengths starting from 430mm (S1) to 445mm (S5 and S6).
Construct Notes/Elements:
I observed one thing concerning the Stumpjumper’s construct specs; Specialised doesn’t need anybody pondering they must restrict themselves on this bike. For a aggressive bike within the path class (my Professional mannequin take a look at bike is underneath 32lbs), it’s received some beefy touches.
First of these can be the SRAM Maven brakes, with 200mm rotors entrance and 200/180mm rears (measurement dependent) for unimaginable stopping energy. Notice the Ohlins mannequin comes with TRP DH-R EVO brakes on 220/203mm rotors. Specialised additionally equips the Stumpys with huge bars, at 780mms on S1 and S2s and 800mms on all bigger sizes. The upper-end fashions’ SRAM XO and XX cranksets additionally embrace bash guards, however one factor not included is a sequence information.
The Stumpy 15 Professional and S-Works fashions roll on pinch flat-resistant Roval Traverse SL II wheels. These rims’ Flat High bead profile requires 85% extra pressure to pinch a tire vs. normal spherical bead rims. The entrance and rear rims are particular, and the wheels supply vertical compliance. The edges are additionally designed to ‘ankle’ side-to-side to enhance traction on uneven surfaces.
Specialised specs all the brand new Stumpys with their Butcher (entrance) and Eliminator (rear) tires. Grid Path casings and a couple of.3” widths come inventory.
Mannequin Lineup:
There will probably be 5 builds of the Stumpjumper 15 and an S-Works frameset out there. Go to Specialised’s web site for full construct specs on every mannequin.
- S-Works Stumpjumper 15 – $12,000
- Stumpjumper 15 Professional – $9,000
- Stumpjumper 15 Ohlins Coil – $8,500
- Stumpjumper Professional – $6,500
- Stumpjumper 15 Comp – $5,500
- S-Works Stumpjumper 15 Frameset – $3,500
I’ve been using the Stumpjumper 15 Professional for a month. You should definitely take a look at my overview article to see the way it carried out on-trail.
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