Specialized Stumpjumper ST Comp Carbon Review

When Specialized released the Stumpjumper in 1981 it was the first-ever mass-production mountain bike. Throughout its 39 year lifespan, it has seen many guises and often pioneered new standards and features not just for Specialized but often for the entire Mountain Bike industry. For 2020, Specialized has three bikes in the Stumpjumper range, all of which are available in both alloy and carbon, with 27.5- and 29-inch wheel options in each model. While following the same frame lines, the ST version we have here is the most conservative in terms of travel and geometry out of all the bikes in the range. This may make the ST seem the timidest sibling on paper but on the right terrain, its grin-inducing rippin’ and tearin’ attitude says otherwise.  

Design and geometry

The ST is the shortest travel bike in the Stumpjumper portfolio, providing 120mm rear wheel travel matched with a 130mm fork. The mainframe sports Specialized’s unique single-sided design and offset-shock mounting, which stems from the Demo8 downhill bike. Specialized state this is used to increase overall frame stiffness over the previous model without compromising on shock positioning or placement of the FSR linkage. The open-sided design makes removing and adjusting the shock a cinch, and the shift to conventional shock lengths and mounting systems is refreshing to see. All carbon Stumpjumper frames use the brand's premium M11 carbon construction all the way up to the flagship S-Works model so you know you’re getting quality right the way through the range. 

Along with this, smaller and larger sizes have different carbon layups to tune the frame feel. The theory being that taller riders on bigger bikes require a stiffer frame compared to smaller riders on smaller bikes, all of which makes total sense. Carved into the rider-tuned carbon downtube is Specialized’s SWAT compartment; a genius design feature that lets you securely stow all your trail essentials inside the frame through a bigger-than-ever door opening. The switch from a pressfit to a threaded bottom bracket shell will simplify maintenance and keep trail time high. There’s room for up to a 3-inch wide 29er tyre too, so you can go proper-plus on your pneumatics. 

The ST geometry is more compact and nimble than gnarly and long, which won’t suit everyone but it’s not like the Stumpjumper range is lacking any radness and sees the EVO model ticking the big hitters' category. The short wheelbase, steep head angle and low BB on the ST turned out to be the fun enhancing potion on certain trails though. 

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Components and build

The Comp model here is the entry-level bike in the carbon range and sees components to shadow this. The Sram NX Eagle groupset works well but comes with a weight penalty and negates some of the weight you save when upgrading from the top tier alloy bike to the first model in the carbon range. While the Fox 34 Rhythm fork and Float DPS performance shock operate on entry-level internals they feel great and their simple nature makes it hard to achieve a bad set up. The own-brand contact points and bar/stem combo are on the money too, but we did end up changing the stock 50mm stem for a shorter 35mm option to sharpen the steering response. Initially, the front end had a tendency to ‘flop’ from side to side when steering. This is down to the combination of both the longer stem and a longer 51mm offset fork, swapping to a shorter stem brings you closer to the steering axis resulting in a sharper, easier to control front end.

The in house, tubeless-ready Roval wheels ride sprightly for the price point however flex is noticeable when pushed hard. This is an ongoing theme with the Specialized tyres too, the Grid casing sidewalls fold too easily and the new GRIPTON rubber compound is too hard and holds the ST back when loading up turns. This is an easy fix though and the market is flooded with great options depending on your local trail conditions and speed/grip preferences. X-Fusion takes care of dropper duties with the Manic post and this performed flawlessly throughout testing. Sram Guide R brakes bring things to a stop with well-modulated feedback and larger - 200mm front, 180mm rear - rotors on the larger sizes to provide more power.

 Ride, handling and performance

The relatively basic spec makes for a refreshingly easy set-up, set the sag and rebound and you’re ready to hit the trails. The riding position feels incredibly natural right out of the gate, this is helped by the bottom bracket being slammed and situated 39mm below the wheel axles, this translates to a proper confidence-boosting in-the-bike feeling. Taller riders may struggle though as reach measurements are short and our size large (445mm reach) bike was comparable with most medium bikes from other brands.

While the suspension system feels good when climbing on technical terrain and the seated position is acceptable, the extra weight of the cheaper components slows the Stumpjumper down on ascents. The FSR suspension kinematic has less anti-squat than most, which means the rear shock has a tendency to bob under pedalling, but the climb lever is effective and easily accessible under the top tube.  Overall it’s not too bad considering the price but it does lack the urgency and kick that some lightweight, short-travel bikes have when powering uphill.

This however, is where things can get complicated. Out on the trail, the Stumpjumper has a split personality and will develop into a love or hate relationship depending on your riding style and where you find your fun. On rough tracks featuring square edge hits and fast repeated impacts it struggles. The compact sizing and steep angles feel unstable when speeds are ramped and the shock lacks mid-stroke support, translating into the rear end riding deeper in its travel more often than we wanted. If you’re attacking hard, this can result in all the trail feedback being absorbed by you as a rider, leaving hands and feet to take the brunt of the impacts. 

That meant we ended up running higher than normal shock pressures and less sag to aid support on rougher trails. While it is effective in regaining front to rear composure, it can take away the much needed initial sensitivity, producing more foot pain and greater rider fatigue. If your riding is rough and flying down beaten up tracks is a regular thing, it may be time to start looking at the 150mm travel Stumpjumper models. These use the same frame as the ST but with a different shock and shuttle, so you can actually switch from one to the other. 

This doesn’t mean we’re writing off the ST though, as there is a huge upside. On smoother trails featuring, big rollers, bucket turns, doubles and side hit jibs, the ST comes alive, giving a genuine fun-enhancement to flow trails. The low bottom bracket situates you in the perfect sweet spot for drilling berm apexes with a warp-speed-generation effect and the short 1192mm wheelbase brings BMX flickability off of trail lumps you never knew existed. This is the moreish side of the Stumpy that makes it hard to put down after a day of riding. If berm blasting is where you find your fun it genuinely thrilling and addictive to ride.

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Verdict

The Stumpjumper ST Comp Carbon has the potential to make you feel like a hero if your riding style slots into its shoes. If your riding is more fast-flow than techy-gnar, the ST is a brilliantly fun option well worth considering but for the latter, better options do exist. For do-it-all duties with better bump-absorbing traits, the longer travel 150mm Stumpjumper might be the answer, or if downhill is a priority the EVO model is one of the most progressive options currently available. 

There are other short-travel bikes that use their travel more effectively too, but the special smile growing fizz on flow trails is missing and that’s where the ST delivers massively.

You can buy the ST from a real bricks-and-mortar shop too and Specialized offer a trustworthy lifetime warranty and a try before you buy demo bike program which makes for a solid investment in the long term. Having lived with SWAT storage for a while we’ve become massive fans of genuinely packless, strapless riding and it’s easy suspension set up and threaded bottom bracket makes it super user-friendly. Probably the biggest take-home though was the fact we were regularly choosing to ride it over a pile of other far more expensive test bikes, especially when we upgraded the tyres.  

Test conditions

• Temperature: 12 to 25 degrees in dry and wet weather
• Trails: Machine built trails, man-made and natural
• Terrain: Blue, red and black graded trail centre and a mix of easy to difficult natural terrain

Tech spec: Specialized Stumpjumper ST Comp Carbon

• Price: £3,800 / US$4,520 / AU$5,900
• Head angle: 68 degrees
• Seat angle: 68.5 degrees
• Frame material: Carbon
• Size: Large
• Weight: 14.30kg
• Wheel size: 29-inch
• Suspension: Fox Rhythm 34 GRIP damper 130mm travel, Fox Float DPS Performance RX trail tune 120mm travel
• Drivetrain: Sram NX Eagle 12-speed groupset
• Brakes: Sram Guide R 200mm/180mm rotors
• Wheels: Roval Traverse 29 alloy wheels, Specialized Butcher GRID GRIPTON 29 x 2.3 front and Specialized Purgatory GRID GRIPTON 29x2.3 rear tyre
• Bar/stem: Specialized forged alloy 45mm stem, Specialized alloy 780mm handlebar
• Seatpost: X-Fusion Manic dropper seatpost
• Saddle: Specialized Phenom Comp saddle