Specialized Stumpjumper ST Comp Carbon 29 Review

Should I Buy This Bike?

The Stumpjumper ST Comp Carbon 29 is a comfortable and easy-going trail bike that is aimed squarely at a less aggressive rider and less aggressive terrain. ST stands for short-travel, and with 120mm or rear and 130mm of front wheel travel, it's not intended to be a brawler or attack the gnarliest lines. Specialized makes bikes for the masses and the Stumpjumper ST Comp Carbon 29 is a good example of that. While many brands are going to extremes with their geometry, the Stumpjumper ST has more conservative numbers that should appeal to a broad range of riders. It's a matter of where and how you ride of course, as this short-travel rig excels on the uphills and thrives on smooth, fast descents and over small to mid-sized chop. It has a wide bandwidth, and nearly all riders, from the seasoned expert to those just starting out, will appreciate the ST Comp as long as it suits the trails you ride.

The Stumpjumper ST is also available with 27.5-inch wheels. The Stumpjumper ST 27.5 has 130mm of front and rear travel. This could be a viable option for shorter riders or those who prefer a slightly more responsive ride. This model is available in four build kits ranging from the aluminum, entry-level, version that sells for $1,850 to the top of the line, $9,500, S-Works model.

If you're looking for a short travel 29er that has a more well-rounded performance, the Ibis Ripley is worth a look. The Ripley just got a complete overhaul that has taken its performance to new heights. We were huge fans of the previous version for its unrivaled playfulness, and the new Ripley continues that trend with far more impressive downhill capabilities and even better climbing performance. We haven't ridden a better all-around short travel trail bike.

Are you looking to get a little rowdier? A mid-travel trail bike might be more up your alley. There are plenty of options, but the longer travel sibling of the ST Comp, known simply as the Stumpjumper, is a real crowd-pleaser with similar conservative geometry and easy-going trail manners. With 140mm of rear and 150mm of front wheel travel, the Stumpjumper Comp Carbon is the same price with a nearly identical build, but with more squish and wider tires that make it more capable when the going gets rough.

Don't want to spend that much? The Giant Trance 29 2 is an affordable short travel trail shredder. At just $2,900, this 29er has an aluminum frame with 115mm of rear travel paired with a 130mm fork. It boasts a slightly more modern geometry that makes it a versatile trail weapon that is a bit more confidence-inspiring on the descents than the Stumpy ST. It comes very nicely equipped for the price and we feel it is an outstanding value. It comes in either aluminum or carbon fiber with four carbon builds ranging from $3,350 up to $10,500.

Frame Design

The Stumpjumper ST frame is built around Specialized's patented Future Shock Rear (FSR) suspension design. This design has the rear shock attached to the bike's top tube and to the rocker link at the seat stays with a yoke that splits around the seat tube. The FSR suspension design is a four-bar system, more specifically a Horst Link, that provides great small bump sensitivity and a very balanced stroke through the bike's 120mm of rear-wheel travel.

All of the new Stumpjumper models feature a new asymmetrical frame design that has a single-sided arm that connects between the top tube and the seat tube parallel to the rear shock. This asymmetrical design was first used by Specialized on their downhill bike and is now seen across the entire Stumpjumper range. The single-sided design is intended to reduce weight while enhancing stiffness throughout the front triangle, and beyond looking different, it seems to work as intended.

The Stumpjumper ST has a “flip chip” which allows the user to easily adjust the geometry slightly to their preferences. By flipping the chip, you can switch between “high” and “low” settings which Specialized claims changes the bottom bracket height by 6mm and the head tube angle by half a degree.

In the bike's low setting, we measured a 67.25-degree head tube angle, a 75.0-degree seat tube angle, and a 330mm bottom bracket height. In the high setting, these measurements changed to a 67.7-degree head tube angle, a 75.4-degree seat tube angle, and a 337mm bottom bracket height.

In either setting, we measured the effective top tube length at 624mm with a reach of 460mm, 438mm chainstays, and a moderately long wheelbase of 1194mm.

Specialized's SWAT (Storage, Water, Air, Tools) system is integrated into the frame design with a slick door on the downtube that allows you to store whatever you choose in the empty space within your frame. Testers who'd never used the SWAT feature before were really impressed with its usefulness and functionality. The new Stumpjumper frames also feature full internal sleeves to simplify the cable routing process, as well as a new, integrated, chainstay protector that Specialized claims to virtually eliminate chain slap noise.

Design Highlights

• Asymmetrical FACT 11m carbon fiber frame

• 29-inch wheels only

• 120mm of FSR rear suspension

• Designed around 130mm travel fork

• Also available in a 27.5-inch version featuring 130mm of wheel travel.

• SWAT storage compartment

• "Easy" enclosed internal cable routing

• Chain silencer to reduce chain-slap noise

• Carbon and Aluminum versions with build options ranging in price from $1850-$9500

• Available in Men's and Women's versions

• Available in sizes S-XL

Downhill Performance

The Stumpjumper ST is a surprisingly capable descender that really shines on smooth flowing trails and in straighter lines at speed over the rough stuff. The bike's 120mm of FSR rear suspension is supple to start with a more supportive mid-stroke that handles small and mid-sized hits well. When it comes to bigger hits, the 120mm of travel is noticeable as you blow through it quite often, but this short travel rig is intended for less aggressive trail riding. The Stumpjumper ST has almost the same exact component spec as its mid-travel sibling, the Stumpjumper Comp Carbon 29.

Specialized's FSR suspension design impressed our testers with its especially balanced feel through its stroke. Small bump sensitivity is great with a supportive mid-stroke that handles high-frequency hits through chunder quite well, especially at higher speeds. Smooth, fast, and flowing descents are where this bike really shines, with an energetic and lively demeanor that begs to be taken up to speed. The spec of 2.3-inch Specialized Butcher and Purgatory tires, front and rear respectively, speak to the less aggressive intentions of the ST Comp. These tires are excellent but don't quite inspire the confidence or deliver the traction of the wider tires we are becoming more accustomed to in loose or more aggressive terrain.

In steeper and more technical sections of trail, the Stumpjumper ST could hold its own. That said, it felt more comfortable in the fall line with a bit of speed. It was confident skipping over small to moderately sized chop, particularly in a straighter line. When the trail got really rough, the bike's short-travel becomes more apparent, and the margin for error decreases requiring a more skilled pilot. Riders seeking a brawling big hit attitude would be better off looking into longer travel trail bikes like the Ibis Ripmo or the Santa Cruz Hightower.

At lower speeds on tight technical descents, it was less impressive; it felt notably uncertain in these situations due to the moderately long wheelbase, taller front end, and skinnier tires. For straighter and fasters trails, the Stumpjumper ST is excellent, but if your daily rides are especially tight and twisty, you might be better off looking elsewhere.

We rode the Stumpjumper ST in both the “high” and “low” settings. As expected, the high setting delivered razor-sharp handling with a touch steeper head tube angle, while the low setting inspired a little more downhill confidence with a slightly lower bottom bracket and slacker head tube. The differences were marginal, but testers found they preferred the low setting as it improved the bike's downhill abilities without compromising much in the climbing department. Either way, testers found the bike to handle well riding downhill in all but slow and tight technical terrain. It responds especially well on smooth flowing trails and carries speed through turns and skipping over rougher sections of trail. Unlike the Ibis Ripley which sought the fun line, playful wasn't a word used by testers to describe the handling characteristics of the Stumpjumper ST as it tended to have a calmer and more planted demeanor.

The ST Comp Carbon is the least expensive carbon-framed model of the Stumpjumper ST, and the component specification reflects that. That said, there are several parts attached to this bike that impressed us. The cockpit setup is one of the most notable elements of the build, with a short 45mm stem and a 780mm handlebar that provide confident and precise steering. The 150mm X-Fusion Manic dropper seat post was a pleasant surprise with a great 1x style remote lever and reliable performance throughout our testing. The handlebar setup is clean with no clutter and comfortable Specialized lock-on grips. Braking is controlled by Shimano SLX brakes with a big 200mm front rotor which testers found to handle the task well. The 2.3-inch Specialized Butcher front and Purgatory rear tires are excellent and make sense given the less aggressive intentions of the Stumpjumper ST, although testers found them to provide less cushion, traction, and confidence of wider options. The Fox Rhythm 34 Performance fork is one of our least favorite aspects of the build, lacking the stiffness and tuneability of higher performance forks.

Climbing Performance

The Stumpjumper ST is a spirited and efficient climber that accelerates quickly and carries speed impressively well. The bike's climbing abilities are not dependent on the use of the shock's climbing switch, although it does help to improve efficiency over extended periods, its active rear suspension helps maintain traction. Its geometry puts the rider in a comfortable climbing position with a notably efficient transfer of power to the drivetrain. Overall, the climbing performance is impressive, although it falters in tight uphill switchbacks and low speed uphill rock gardens.

All of our testers agreed that the Stumpjumper ST felt fast on the climbs, especially long climbs where you settle in and crank for an extended period. The Stumpjumper ST's FSR rear suspension design is quite active, although it performs quite well with the shock in the “open” position. For extended periods of climbing, testers found that switching the rear shock to the “trail” position provided a more supportive pedaling platform while still allowing the rear suspension to be active to help maintain traction over rocks and loose dirt. The “firm” position of the rear shock is rarely needed, except on paved or smooth dirt roads where it helps to maximize efficiency.

In general, we found the geometry of the Stumpjumper ST to provide a comfortable climbing position. The reach is moderate by today's standards and doesn't stretch you out too far, with a nice wide handlebar and spacious cockpit. The seat tube angle is right around the sweet spot, at 75.0/75.4 degrees, and puts your weight right over the bottom bracket for maximum pedaling efficiency. With the bike's bottom bracket height of 330/337mm, pedal strikes were not super frequent, but attention must be paid while pedaling through rocky sections, though Specialized has spec'd slightly shorter 170mm cranks on all sizes of the ST Comp. One of the highlights of the build is the spec of a Specialized Phenom Comp saddle which is especially comfortable for those long seated climbs.

The Stumpjumper ST has a smooth, composed, and fast feel when climbing. Most bikes in this travel range share a similar feeling on the ascent, but the ST Comp felt faster than most, especially on smoother and less technical sections where it carries speed well. We found the climbing performance to be less impressive in tight uphill switchbacks and low-speed technical sections where the bike's tall front end and moderately long wheelbase made it a little unwieldy. Setting up well in advance for uphill corners, perfect line selection, and maintaining momentum through technical climbs are necessary on the ST Comp. The 2.3-inch Specialized Purgatory rear tire generally offers plenty of uphill traction, although we found the narrower width of the tire to dig into loose dirt or sand when climbing more than wider tires.

Specialized spec'd a Shimano XT 11-speed rear derailleur, SLX shifter, SLX cassette to handle the drivetrain duties on the ST Comp. While we are typically partial to 12-speed drivetrains, we must admit that the shifting is precise and the range offered by the 11-46 tooth cassette and 30-tooth chainring is adequate for most riders most of the time.

Photo Tour

Value

In this day and age, we feel the Stumpjumper ST Comp's relatively well-rounded performance, functional component specification, and $4220 price tag represents a good value. This bike's practical geometry works well and is well suited to a large portion of the riders out there. It looks good, has great mild trail manners, with a component spec that simply gets the job done. If you're looking for an XC-oriented short travel trail bike with a carbon frame, we think the Stumpjumper ST Comp is a nice choice at a reasonable price.

Conclusion