2015 Specialized Stumpjumper FSR Comp Carbon 6Fattie

2015/16 Specialized Stumpjumper FSR Comp Carbon 6Fattie

Size Tested: Medium

Geometry: Here

Build Overview:

  • Fork: Fox 34 Plus Performance
  • Shock: Fox Float Performance DPS
  • Seat Post: Specialized Command Post IRcc, 125mm drop, 12 position adjustable
  • Drivetrain: SRAM GX
  • Brakes: Shimano Deore

Wheels: 27.5+

Travel: 150 mm front, 130 mm rear

Blister’s Measured Weight: 31 lbs with flat pedals

MSRP: $4,300

Reviewer: 5’8”, 160 lbs

Test Location: Park City, Utah

Test Duration: 30 days

Tom Collier reviews the Specialized Stumpjumper FSR Comp Carbon 6Fattie for Blister Gear Review.
Specialized Stumpjumper FSR Comp Carbon 6Fattie


Specialized has been making their do-it-all Stumpjumper bikes for decades. But this time around, the line is their most diverse and featured yet. 15/16 Stumpjumpers feature Autosag, SWAT storage, and 27.5, 29, or 27.5 Plus tires. No matter your wheel size of choice, Specialized has a Stumpjumper for you.

The Specialized Stumpjumper FSR Comp Carbon 6Fattie (henceforth in this review referred to as the Stumpjumper) is an interesting and challenging bike to review, since it offers quite a bit of new technology (including 27.5×3” tires and an inspiring ride quality), but at the same time, it has a number of flaws. That combination makes for a lengthy review, so bear with me.

Tom Collier reviews the Specialized Stumpjumper FSR Comp Carbon 6Fattie for Blister Gear Review.
Tom Collier on the Specialized Stumpjumper FSR Comp Carbon 6Fattie, Park City, UT.

My first foray into Plus-tired bikes came this summer at Scott’s product launch. I enjoyed my time on those bikes, but it wasn’t long enough to conclusively answer some of my questions about Plus-tired bikes, or see whether I could (or should) shoehorn one into my quiver. Getting on the Stumpjumper offered an opportunity to tackle those questions and see how Specialized’s offering stacked up against Scott’s.

The questions, in particular, that were lingering for me: (1) Are Plus-tired bikes a novelty, or are they practical for all-around use? (2) Are they capable enough to supplant a bike like my Santa Cruz Nomad? (3) Do I need one?

The Build

The Stumpjumper’s drivetrain is all SRAM GX. The brakes are Shimano Deore. The dropper post, bars, stem saddle, and hubs are all Specialized’s house brand.

The GX drivetrain performed exactly as my first GX drivetrain did, which is to say, well.

The Shimano brakes were okay at best. The extra inertia from the larger wheels and tires might have made them feel weaker than usual, but I’m going to put most of the blame on the Resin Ice-Tech brake pads.

All of the Specialized components are decent, and the highlight is definitely the dropper post lever. It is very similar in feeling to a SRAM shift lever, and definitely more solid feeling than the KS Southpaw lever. This is the best dropper lever I’ve used, hands down. I now want one for my KS and Thomson posts–though turns out, it isn’t compatible with the Thomson, but works beautifully with my KS post.

However, the dropper itself tops out hard. Luckily it wasn’t too much of a problem, and I never had the seat actually hit me. The post is very easy to push down, but there is lots of play in the post.

The bars are 750 mm wide, with a bend very similar to Easton’s. I got along really well with those dimensions. Anyone bigger than me will probably opt for wider bars.

The Specialized Body Geometry Henge Comp Saddle felt great during a driveway test, but after about 20 minutes into a ride, it would always became uncomfortable for me. Of course, your mileage may vary depending on the shape of your rear.

The Specialized hubs are pretty standard items with standard engagement. Not quick, not terribly slow, 15 degrees between points of engagement. The rims have a 29mm internal width and a hookless design. I found it easy to mount a tubeless tire on them, and had no issues with burping.

The small, 28t chainring is definitely geared toward slower riding and steep climbs. It makes it fun to sit and crawl up super steep climbs.

The Fox 34 Plus Performance fork is extremely wide–to my eyes, wider than necessary to clear the tire. It looks somewhat ungainly, but it does offer copious tire clearance. Otherwise, in terms of the damper and spring, it is the same as the standard Fox 34. I found it to be adequately stiff, but with the 3” tires, tire-casing flex was much more noticeable than fork flex. Most notable this year is the departure from referring to the fork’s three compression settings as “Climb,” “Trail,” and “Descend” and instead calling them “Firm,” “Medium,” and “Open.”

Tom Collier reviews the Specialized Stumpjumper FSR Comp Carbon 6Fattie for Blister Gear Review.
Fox 34 Plus Performance fork

The fork took a bit of time to break in, but then felt very good. The 51 mm offset is great. Combined with the 28.5” outside diameter tires, the handling ends up being surprisingly quick and responsive. It feels quicker than a 29er fork with a 51 mm offset, or a 27.5 fork with a 44 mm offset. I think this is one of the features that many other reviewers have reacted to positively on these plus sized bikes.

The front tire is a Specialized 6Fattie Purgatory Control with a 60TPI, tubeless-ready casing and a folding bead. It measures 3” wide and weighs 980 grams. The rear tire is a Specialized 6Fattie Ground Control tire with the same casing and width. It weighs 1045 grams.

NEXT: Sizing, Geometry, Etc.

5 comments on “2015 Specialized Stumpjumper FSR Comp Carbon 6Fattie”

  1. Sort of minor question…. the Specialized dropper lever is not compatible with a thomson? I’ve used one with mine for a year. Definitely a bit of a pull but works fine.

    • I know Thomson changed their setup at some point last year and flipped around how the cable is oriented. The post I have requires the swaged cable end to attach at the bottom of the post. The Specialized lever requires that the swaged end terminates at the lever. If you are determined, you could swage a second end onto the cable and make it work, but short of that it isn’t easily compatible.

  2. Great review. Love the depth. Every Specialized I’ve owned has been expensive — from pedal replacement costs due to their ridiculously low bottom brackets. No easy fix for taller guys, either.

    OTOH, it’s much easier to add a volume reducer to a Fox shock to reduce bottoming than it is to remove a non-existent one due to excessive ramp up. I like S’s approach in this regard.

    • Thanks Tom. I agree that it is easier to add a reducer than remove a non-existent one. I hope to add one to this bike to try it out. I’m not sure whether or not I’ll be able to get enough ramp though. It is very deficient and the shock already has a stroke reducer in it so I’m not sure how much I’ll be able to fit in there in terms of spacers.

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