Specialized Stumpjumper 15 Review

The Specialized Stumpjumper 15 eliminates everything unnecessary for having fun on the trail. Our test reveals where the pursuit of reduction leads.

Instead of pushing the innovation envelope, the team in Morgan Hill, home of Specialized, is taking a step back. With the Stumpjumper 15, the Americans are not only phasing out the Evo versions with more travel but are also returning to a very classic four-bar linkage rear suspension with the new Stumpy.

So now, there is only one Stumpjumper platform rather than two as in the past. Except for a special model with an Öhlins suspension, every Stumpjumper now features 150mm of travel up front and 145mm at the rear. The single-pivot rear with flex stays from the predecessor (which only had 130mm of rear travel) has now been axed in this travel class. By returning to the classic FSR suspension, Specialized relies on a 100% predictable and time-tested rear suspension design that strikes the best balance between lightweight construction and functionality. The asymmetric frame design of the old Stumpy is also a thing of the past.

The geometry values are not completely identical to the previous model, but they are very close. With an adjustable head angle via the headset and a flip-chip in the chainstays to adjust the bottom bracket height, Specialized offers customization options to suit every preference. In the slackest setting, the head angle reaches 63°. In our test, we found the middle setup with a low bottom bracket to be the best.

The actual tip, if you prefer a more playful handling, is to choose a frame size smaller. Because the bike is available in 6 frame sizes. And the seat tube differs in the 6 frame sizes by just 8 centimeters. Generally, you can achieve any seat height in at least two, often even three frame sizes. We had the bike in size S3, which corresponds to an M. But for the test, we also rode an S4 bike, which worked well too, but was less playful.

Anyone who orders a different rear triangle from Specialized can swap the 29er rear wheel for a 27.5 wheel. From the factory, only the smallest Stumpy rolls on a mullet setup.

You really have to look at the details to find the evolutionary steps from the predecessor in this bike. With a frame weight of 2260 grams, the frame, despite the Horst Link suspension, is only 200 grams heavier than its predecessor (with only 130 mm of rear travel). Compared to the old Stumpjumper Evo, the frame is almost 400 grams lighter.

Although the new Stumpjumper comes stock, except for the version with Öhlins suspension, with only 150 mm in the front and 145 mm of rear travel, a comparison to the old Evo version with 160 mm of front travel is practically inevitable.

Specialized’s aggressive marketing images make it clear: The Stumpy is more than a trail bike. And considering these images, a frame weight of 2200 grams is remarkably low. For comparison: The Canyon Spectral CF weighed 600 grams more on our scale with 5 mm less rear travel. A complete weight of 13.7 kg (Pro version, without pedals, tubeless tires) is outstanding for a bike in this class.

Specialized shows that lightweight construction does not come at the expense of durability by offering a lifetime warranty. The lifetime frame warranty now also extends to the suspension bearings. This has always been a promise with which Santa Cruz in particular could score points. And such a promise is only made if the risk behind it is considered very low.

When it comes to cable routing, they go radical and reveal a little secret. The carbon Stumpy has no provision for a mechanical shift cable. So, it must be ridden with a wireless drivetrain. And since it’s unlikely that Specialized will rely solely on SRAM for shifting components in the coming years, a wireless electronic drivetrain from Shimano will probably be available soon. The product managers at Morgan Hill clearly know more than we do.

The remaining cables for the dropper post and brake enter the frame traditionally at the side of the head tube and are guided through the frame by integrated channels to their destinations. This is how it should be. This attention to detail is what Specialized puts into their bikes.

The long-overdue step to make the SWAT storage door finally waterproof has also been achieved. Specialized accomplishes this with a new closure that features a rubberized seal. This effectively prevents deterioration inside the down tube.

The installed Bike Yoke Revive Max with a 34.9 mm diameter is not only known for its absolutely robust construction but can also be bled on the trail with just a mini-tool. The thicker diameter, which more and more manufacturers are now adopting, makes the dropper post not only stiffer overall but also more resistant to wear. Anyone who has pressed down on a Bike Yoke post can feel the difference compared to most other manufacturers.

We tested the new Stumpy 15 in the Pro version and were amazed. Weighing in at 13.7 kilos without pedals, the weight is truly impressive and makes it fully tour-worthy. For comparison: The bike is almost a kilo lighter than Canyon’s Spectral top model or significantly lighter than the Trek Fuel EX. The Stumpjumper is a bike that is fun to ride uphill. The climbing position is slightly more upright than most All-Mountains and has also proven to be quite comfortable on longer rides.

What’s noticeable when pedaling uphill is that the rear suspension is incredibly sensitive. The slight movement of the shock while climbing is so minimal that we didn’t use the shock’s platform function. With the new Genie damper system, responsible for its sensitive response, Specialized is once again paving its own path. The frame can also be used with any other conventional shock, but it is always shipped from the factory with the new Genie damper.

Behind the bulky design of the new Genie shocks lies an exceptionally large air volume, achieved through a second air chamber. Specialized, in collaboration with Fox, adds an extra air chamber around the regular air chamber of a Float shock.

The larger the air chamber, the more sensitive the suspension element can work. You can think of it like pressing a large exercise ball with your hand compared to a small one. The Stumpy here, with its Genie shock, is definitely more like the exercise ball and can finely tune over all bumps, especially the smallest ones. This allows the rear wheel to maintain more ground contact and therefore build more grip.

In the last third of the travel, a piston separates the outer air chamber, radically changing the air volume and thus the suspension characteristics. With the smaller air chamber towards the end of the travel, the progression in the shock increases significantly. And indeed, you can barely bottom out the shock on the trail.

With the Genius technology, Specialized has created a dual-phase shock absorber that works super sensitively and still offers very good bottom-out protection towards the end. The concept works well on the trail. However, one should not confuse this damping concept with the function of an external reservoir.

Because the second air chamber initially has nothing to do with the oil volume of the shock absorber. If you hammer the Stumpy down long descents towards the valley, the shock absorber develops a bit more temperature than one with a reservoir. If you regularly descend over 300 meters at a stretch and place a high value on consistent performance, you can also install any normal shock absorber with a reservoir in the Specialized.

What stands out positively on the downhill is that Sram’s promise with the Maven to finally deliver enough braking power actually holds true. The brakes are absolute stoppers, which can be modulated very well with minimal hand effort.

If there’s a criticism to be found on the downhill, it would most likely be about the tires used. While they offer good grip, the trail version has a relatively soft casing. Although we didn’t get any flats despite a few pinch flats during our test, we would have liked the tire to sit more firmly on the rim.

Other than that, there’s really nothing to complain about on the trail. Despite having just 150 mm of travel, the bike rides like a board, and what’s particularly pleasant is that nothing rattles even in rough sections. That’s how it should be. In the setting with a neutral head angle (64.5 degrees), the bike is already on the stable side. Such traction and confidence on the downhill is not something you would normally expect from such a light bike. But the Stumpy impresses with direct handling and confident riding even on gnarly trails.

With an entry-level model starting at 6500 €, the new Stumpys are not cheap. For comparison: With Canyon, you can almost get the top model of the Spectral CF for the same amount of money. Our test bike in the Pro version costs 9500 € MSRP. The presentation of the more affordable aluminum models is still pending. With our comparison function, all models can be easily compared with all bikes from our extensive market overview. Simply click on the arrow icon and go to the comparison.