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Specialized Stumpjumper News | Best Trail Bikes

Specialized Stumpjumper News | Best Trail Bikes 2020-10-14Leave a comment

electrical bike Specialised Stumpjumper Information | Finest Path Bikes

I’m used to Specialised making nice bikes. And after they make a terrific bike, it’s normally a very (actually) nice bike. Examples embrace the Tarmac, Creo SL, Diverge, Epic (and Epic Evo), Enduro. The corporate typically units the benchmark for efficiency that everybody else tries to fulfill.

The previous Stumpjumper—the guts and soul of the model’s mountain bike line—felt like an odd miss from an organization that’s normally so dialed. That’s not as a result of it was horrible (it wasn’t) however as a result of it was solely okay when different firms supplied nice. The suspension was good, not implausible, and the geometry regarded dated from day one. Add to {that a} confounding mixture of fashions—brief journey, lengthy journey, Evo, 27.5-inch wheels, 29-inch wheels, numerous restricted editions—and it wound up being a considerably neglected bike.

As of as we speak, there’s a brand new Stumpjumper. With 130mm rear journey and 140mm within the entrance, it’s a extra historically path centered bike than the 150/160 Evo that launched final week. The brand new Stumpy is the lighter and higher climbing, with updated geometry, some acquainted options, and a few shocking modifications.

The New Stumpjumper

The brand new Stumpjumper is a 130mm (rear) 140mm (entrance) path bike on 29-inch wheels. This journey splits the distinction between the earlier 140/150mm “lengthy journey” Stumpjumper and the 120/130mm Stumpjumper ST. There aren’t any extra 27.5 fashions.

The brand new Stumpy lands in six fashions: two aluminum priced at $2,199 and $3,199, and 4 carbon promoting for $3,999, $4,699, $6,999 and $9,499.

It adopts Specialised’s Type Particular Sizing system and is available in six choices: S1, S2, S3, S4, S5, S6. You’ll be able to consider these as roughly equal to extra-small by means of double-extra-large, although the geometry lets riders dimension extra on most well-liked really feel than their peak. Measurement down for a extra playful bike, dimension up for extra stability.

the new stumpjumper's geometry

The brand new Stumpy’s geometry


The geometry is in keeping with present developments, and definitely longer and slacker than the earlier SJ. A brand new Stumpjumper in S3, in low, incorporates a 450mm attain, 65-degree head tube angle, 76 levels seat tube angle, 432mm chainstays, and 1200mm wheelbase. Numbers for a dimension medium within the earlier Stumpjumper 29 are 425mm attain, 66.5-degree head tube angle, 74.5-degree seat tube angle, 437mm chainstays, and a 1169mm wheelbase. One other geometry change: new bikes use 44mm offset forks (the previous-gen used 51mm offset). A flip-chip within the shock’s rear eyelet gives 0.5-degrees of angle adjustment and +/- 7mm of BB peak adjustment.

Carbon fashions carry over the SWAT in frame storage from the earlier era bike. Sadly, storage capability is similar, and the brand new bike doesn’t match the brand new Evo’s candy in-frame water storage bottle.

Different carry-over options embrace threaded BB, inner hose and housing routing, the asymmetrical “sidearm” strut from prime to seat tube, and the lumpy chainstay protector that silences chain slap, and a 1x particular design.

Weight was a spotlight for the brand new design, so along with pulling 100 grams out of the carbon body, all fashions get forks with 34mm chassis, inline shocks, and a couple of.3-inch broad tires entrance and rear. All fashions use SRAM 1×12 drivetrain.

Bye Bye FSR

In 1993, Specialised launched its first suspension bike: the FSR. Designed with the assistance of Horst Leitner at AMP Analysis, it was a four-bar design with a pivot within the chainstay between the principle pivot and the rear axle. This pivot turned often known as the “Horst Hyperlink” or “FSR Hyperlink.” And for over 20 years, Specialised full suspension bikes featured the Horst Hyperlink.

1994 specialized s works fsr

Specialised was extraordinarily aggressive about defending its FSR patents. Aggressive to the purpose of bullying. It was the supply of a lot disdain directed in the direction of Specialised then, and a few nonetheless harbor it as we speak. The FSR patent wars affected firms throughout the globe. Someone might write a novel about them: I actually have a couple of tales, and thru the years, I’ve heard many extra.

The purpose of this isn’t to bash Specialised for its previous actions or to argue about the benefits of one design versus one other. The purpose is Specialised was absolutely invested within the know-how and believed it gave their bikes such a bonus that they tried to make sure that solely Specialised bikes—and some smaller firms that obtained a license like Titus and Turner—had a Horst Hyperlink.

(A few of the FSR patents lately expired, which is why you’ve seen a large enhance within the variety of bikes utilizing the design.)

That’s why it’s such a tectonic shift that the brand new carbon Stumpjumper doesn’t have a Horst Hyperlink: Essentially the most well-known mountain bike mannequin not makes use of its signature suspension design. For many years, a design Specialised invested: its authorized workforce in court docket whereas its engineering groups frequently labored to refine the design as mountain bikes developed.

2021 specialized stumpjumper carbon rear triangle

No extra Horst Hyperlink for the Stumpjumper Carbon


The brand new carbon Stumpjumper employs a single pivot design with flex stays, a design that’s most likely older than FSR and definitely not new or distinctive. I’ll let the enginerds argue in regards to the theoretical kinematic professionals and cons of the varied designs on the market. I’ve been driving full suspension bikes since 1993 (I owned a first-generation FSR) and testing full suspension bikes since 1995. And if I’ve realized one factor about full suspension, it’s that even probably the most “superior” design will be made poorly and journey like crap and that effectively accomplished “easy” system can journey superbly. The small print matter greater than the system.

I requested Steve Saletnik, the Stumpjumper’s product supervisor if there have been any downsides—purposeful or perceived—to shifting away from the 27-year previous FSR design. Unsurprisingly he mentioned no, “The mix the workforce achieved with the Rider-First chassis, the focused flex within the seatstay that mimics a pivot, the kinematics, and the Rx [shock] tune all exceeded the targets we set out on, so shifting away from a Horst pivot was not a tough alternative for this bike (particularly with the related weight financial savings).

2021 specialized stumpjumper

Alloy Stumpjumper fashions nonetheless use the Horst Hyperlink as a result of aluminum can not flex like carbon


After all, I didn’t anticipate Saletnik to say, “Sure. Let me listing all of the drawbacks to the brand new model of our best-known mountain bike mannequin for you.” The FSR four-bar design had a rattling good three-decade run, however the business’s collective engineering data, applied sciences, and the very sport of driving a mountain bike has modified a lot in that point. I’m certain it was the topic of a lot inner debate, however ultimately, the workforce at Specialised felt they wanted to depart the Horst Hyperlink behind for the Stumpjumper to maneuver ahead.

And to be truthful, they’re not abandoning the Horst Hyperlink fully: it’s nonetheless discovered on the model’s longer-travel bikes: the Stumpjumper Evo, the Enduro, and the Demo downhill bike. And aluminum variations of the brand new 130/140mm Stumpjumper use the Horst Hyperlink for a easy cause: aluminum can’t be tuned to flex like carbon repeatedly.

The New Carbon Stumpjumper—Less complicated Equals Lighter

As I’ve famous in a couple of latest critiques, fashionable path bikes are heavy. It’s not unusual for a mid-travel 29er, even with a higher-end construct, to weigh 30 kilos or extra. That’s the results of the transfer to greater wheels, longer and slacker geometry, fashionable options like dropper posts and wider rims, and types placing extra deal with constructing a stable and dependable bike with glorious suspension efficiency.

However the want for lighter bikes is enduring and virtually common. One of many largest causes Specialised deserted its signature FSR suspension was to chop weight. By eradicating its signature chainstay pivot, Specialised claims they may make the rear triangle 55 grams lighter whereas additionally enhancing stiffness (lateral and torsional). Different refinements helped reduce one other 45 grams from the body, bringing chassis weights right down to a claimed 2420 grams (5.3 kilos). That’s able to construct weight: painted body with shock and every thing else.

the stumpjumper carbon frame

The Stumpjumper carbon body weighs a bit over five-pounds. You should purchase the body just for $2,799


That helps obtain some respectable full bike weights. Saletnik, the Stumpjumper’s product supervisor, offered the next reference weights: S-Works ($9,499) – 27.3 lb., Professional ($6,999) – 28.43 lb., Knowledgeable ($4,699) – 29.3 lb., Comp ($3,999) – 30.4 lb. The bikes in your native store’s flooring could also be completely different as a result of, as Saletnik famous, “These are based mostly on a pattern dimension of 1 bike, so some variance in manufacturing bikes is feasible.” Nonetheless, Saletnik acknowledged that these weights embrace tubes, which weigh about 300 grams. The bikes ought to be considerably lighter when transformed to tubeless.

I’ll admit to being underwhelmed once I first learn these weights. However the extra I poked round, the extra I spotted that they’re fairly good. The $6,900 Yeti SB115 I examined weighed 27.6 kilos—a Stumpjumper Professional transformed to tubeless will likely be near that. The Stumpjumper has extra journey (130/140mm vs. 115/130mm), extra up-to-date geometry, SWAT in body storage, the sweeter driving GRIP2 damper in its Fox 34 fork (the SB115 has the lighter FIT4), and an easier-to-service threaded BB.

The Secret Sauce—Shock Tune

Since it’s outstanding and straightforward for the world to see, the lever or levers that make up a rear suspension design are likely to get probably the most consideration. Although it’s hidden from view, shock tune is simply as vital and impactful because the rotation of the lever(s). What you are feeling once you journey a motorbike is the system: a mix of levers and shock tune. Lengthy gone are the times once you’d slap an off the shelf shock in a motorbike and name it good. Manufacturers now work with suspension suppliers on shock tune to get one of the best efficiency from a motorbike.

specialized stumpjumper flip chip

An adjustable rear shock eyelet supplies geometry adjustment.


However a couple of manufacturers, Specialised is one among them, go a step additional and have in-house suspension R & D groups that develop proprietary tunes and damper applied sciences past the inventory choices supplied by the suspension suppliers. Dig by means of Specialised’s full suspension archives, and you’ll find a number of noteworthy concepts to come back out of this workforce: in-house fork and shock designs, the ITCH Change, and the BRAIN amongst them. As they do for each Specialised full-suspension mannequin, this workforce developed the brand new Stumpjumper’s shock tune.

The aim with the brand new Stumpjumper was to make it pedal even higher than ever to enrich its lighter weights. The workforce settled on a digressive tune claimed to offer further low-speed damping for crisper pedaling and assist, however with considerably mild high-speed damping to maintain the suspension easy and supple on greater bumps.

2008 stumpjumper fsr pro frame with brain and in house designed shock

2008 Stumpjumper FSR Professional body with BRAIN and in-house designed shock.


Word that Specialised’s digressive compression tune is completely different from the regressive tune Trek makes use of on its 130/140mm Fuel EX path bike. I requested a suspension skilled to clarify the distinction. They mentioned, “Merely put, digressive is a comparatively flat drive curve after platform threshold peak. It has a threshold level that creates a platform after which maintains an identical drive curve all through the complete shock compression.

“Regressive additionally produces a platform threshold peak however then really drops in damping drive after the platform threshold peak. It then begins climbing as shock velocity builds throughout shock compression (terrain enter).”

The Stumpjumper does have a historical past with regressive damping. Previous fashions used a riff of the BRAIN inertia valve damper discovered on the Epic. Requested in the event that they thought of making use of the BRAIN to the Stumpjumper (once more), Likelihood Ferro of Specialised’s suspension R&D mentioned, “We weren’t in search of a kind of twin mode suspension that goes from agency to gentle like BRAIN. As a substitute we had been focusing on a extra seamless suspension really feel that provides us simply sufficient assist with out being overkill for tough terrain.”

compression damping in red starts high for initial support, then flattens to suck up bigger hits rebound damping in white starts low to keep the suspension sensitive, then ramps up to control return when the shock moves deeper in its travel

Compression damping (in pink) begins excessive for preliminary assist, then flattens to suck up greater hits. Rebound damping (in white) begins low to maintain the suspension delicate, then ramps as much as management return when the shock strikes deeper in its journey.


When the shock strikes the opposite route, it employs what Specialised calls a “customized progressive rebound tune.” It’s quick on small bumps to maintain the suspension vigorous and responsive however will increase shortly to manage the return on deeper hits. The declare is that this tune retains the suspension fluttering on smaller bumps, which helps preserve traction, however eliminates the catapult feeling on g-outs and different large impacts.

Then there’s the spring’s tune, which works hand-in-glove with the bike’s leverage fee. Specialised says the brand new Stumpjumper has a “very progressive leverage fee with a steep slope,” designed to assist it provide preliminary sensitivity, mid-stroke assist, and bottom-out resistance. No shock there: just about each model shoots for a similar factor.

The leverage fee works on a “bigger quantity [air] spring to offer a extra gradual spring ramp.” Specialised says this leads to a flat spring curve that enables the Stumpjumper to make use of extra journey over small and medium bumps, with a pointy development on the finish of the journey to tame greater hits. Once more, nothing earth-shattering right here.

2021 specialized stumpjumper leverage curve and spring curve

The Stumpjumper’s leverage curve (left) works with the shock to provide the spring curve (proper)


However then there’s nothing audaciously new in regards to the new Stumpjumper. Even so, in the event that they’ve accomplished a great job and minded the main points, it ought to journey superbly.

I’ll have a full report on the brand new Stumpjumper’s on-trail efficiency quickly. Hold your eyes peeled right here and over at our YouTube channel.

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