First Ride Review: 2019 Specialized Stumpjumper Expert Carbon 29
I’d be lying if I told you that Specialized has just unveiled its most advanced and refined Stumpjumper yet. Because there are actually three new Stumjumper models for 2019. And they’re all rather snazzy.
This year we’re going to see two additional models of Stumpjumper join the range. There’s the new short travel Stumpjumper ST, which replaces the outgoing Camber. Then there’s the return of the Stumpjumper EVO, with its turbo-charged parts spec and unique mainframe that offers much slacker and longer geometry for going full-rad. (For more information on these two bikes and the wider Stumpy range, check out the full news story here).
The bike in the middle of those two is the good ol’ Stumpjumper we all know and love. Except, well, everything’s kinda different.
A month ago I was invited out to Ainsa in Spain to be one of the first to see, touch and ride the new 2019 Stumpjumper triplets. Located in the foothills of the Pyrenees, Ainsa sits within the Zonezero region (pronounced as “thona-thero” in your best Spanish accent). The name may be familiar to some, as Ainsa has played host to a round of the Enduro World Series before, and is due to host another round in September of this year. I was informed that there’s approximately 1200km of trails in the Zonezero region, with 20% of those being dedicated singletrack, much of which is built and maintained by volunteer groups. There’s plenty of elevation at those trailbuilders’ disposal, and with the rocky trails surrounded by snow-capped mountains, and evidence of old castle ruins and church buildings found around every corner, the riding here has a distinct backcountry feel. Ideal territory for a long travel trail bike.
For extra effect, the three-day launch of the 2019 Stumpjumper was juxtaposed against the backdrop of a beautiful 500-year old monastery. A contrast of very old and very new.
Specialized let us pick and choose what bikes we wanted to test, and with each platform being available in two wheelsizes and multiple build levels, there was no shortage of choice. While I did get saddle time aboard most of the new models during the launch, it was the regular (or ‘long travel’) Stumpjumper 29 that I spent the most time riding, and it’s the bike I’m going to go into a little more detail here.
Replacing the previous Stumpjumper that was released back in 2015, the new version aims to carry on the Stumpy’s popularity as a do-it-all trail bike, while bringing the geometry up to date and stepping up the bike’s descending prowess – something that Specialized wanted to improve over the previous version.
The new Stumpy is available in both 29in and 27.5in wheelsize options and comes standard with 2.6in tyres and a 150mm travel fork. The frames and geometry are pretty similar, though the 27.5in model features 150mm of rear travel, while the 29er gets 140mm. There are no 6Fattie models for 2019, but each frame has clearance for plus tyres built into it. For the Stumpy 27.5, you can go up to a 27.5×3.0in tyre, and the 29er Stumpy has clearance for mahoosive 29×2.8in tyres if you really want to go there.
Starting at £1700, there will be two alloy Stumpjumpers and several carbon options that top out at £8000 for the SWORKS model. Sizes range from Small through to X-Large, though there’ll also be an X-Small size in the women’s specific builds (same frame, but with specific components and suspension tune).
The model I rode is the Stumpjumper Expert Carbon 29, which retails for £5000 and is currently available from Specialized dealers as of today.
That Sidearm Frame
One of the biggest areas of focus during the Stumpjumper’s three-year development was chassis stiffness. Jason McDonald, one of Specialized’s MTB Design Engineers that led the project and was joining us for the three days of riding, explained that he and the team weren’t convinced the old frames were stiff enough. Up until recently though, all frames (road and mountain bike) were tested in-house using the same test rig. So McDonald and the team developed their own mountain-bike specific test rig to quantify what testers were feeling out on the trail.
Along with welded alloy mules, carbon prototypes were developed in Specialized’s facility in Morgan Hill, California, and were modified through testing by adding extra layers of carbon in certain areas to gradually increase stiffness. The goal was to see how far they could push things before they ended up with a frame that was too rigid, because at some point you can have a frame that has so much material that it becomes unnecessarily heavy, and also uncomfortably stiff to ride. Through lab and on-trail testing, McDonald and the team have settled on what they believe to be the sweet spot.
Part of that development period involved testing various asymmetric frame designs, and it is the distinctive Sidearm design immediately smacks you in the face when you first see the Stumpjumper in the flesh. Inspired by the Demo downhill bike, the Sidearm construction isn’t just for looks – it physically braces the front triangle to improve rigidity, and also beefs up the junction for the main suspension linkage. The shock is offset to the non-drive side where it is partially hidden by the Sidearm brace.
For 2019 every carbon Stumpy model features a full carbon frame (no hybrid frames with alloy rear ends), and they’re all constructed from the same FACT 11m carbon fibre. Depending on the size, the frames have dropped 150-250g of weight over the old Stumpy – except for the new all-carbon Comp frame, which has dropped a substantial 500g over the previous alloy/carbon hybrid frame. Despite the convenient weight drop, Specialized firmly states that stiffness was the main priority with the new frame. Out back you’ll see a wider main pivot and the addition of a seatstay bridge, which increases rigidity through the back end.
Also beefed up on the new Stumpy is the use of a shorter and stouter 34.9mm diameter seat tube. This has increased both frame stiffness and standover clearance, but just like the Enduro, the Stumpy will now readily take a longer travel dropper post without limiting the saddle height range. In fact, even with the new 160mm travel Command IRcc dropper, Specialized states the min/max saddle heights are the same for each frame size as they were with the old Stumpy.
Practicality Not Proprietary
Aside from the move to a chubbier seatpost, the Stumpy has shed much of the proprietary tech from the old model. No longer will you find a press-fit bottom bracket, with a threaded shell taking place of the PF30 of old. The rear shock is now a standard metric size, so you can pretty much wang any metric shock you’d like in there, including a coil shock. The hubs remain Boost-width, and the headset uses direct drop-in cartridge bearings.
Practicality extends to the internal cable routing, which now has internal nylon guide tubes throughout to save you having to fish around with magnets and picks. Even the SWAT compartment has been refined with more storage volume and a lower profile trapdoor.
While it’s only a small detail, Specialized has gone all sciencey on the design of the chainstay protector in an effort to reduce noise and chainslap. A speciality ‘high speed shaker machine’ was built so the engineers could shoot high-speed video to evaluate chain movement while the bike was bouncing around inside. In super slow-motion, they could see the wave that the upper chain would create every time the rear wheel encountered a bump, with the wavy chain then accelerating before slapping against the frame. To break up the wave, they developed different shaped protectors and experimented with soft mastic-style materials to see how much they could quieten down the noise. The end result is a thick, bolt-on protector that has three nubs moulded into it at specified points. Like the downtube armour, this protector can be removed and replaced if it ends up being damaged.
Specialized has retained the overall shape of its iconic FSR suspension design for the new Stumpy, though considerable experimentation was carried out in order to assess alternate leverage curves by using different linkages and rear shocks.
The ultimate goal was to get the rear suspension feeling as coil-like as possible, with more reliance on the spring itself to help boost the bike’s mid-stroke support. Instead of looking to shock damping to provide pedalling efficiency, Specialized developed the Stumpy’s kinematics to give it a more supple starting stroke and a firmer mid-stroke than the old bike, but with the same bottom-out force. In short, it’s designed the kinematics around the latest air shocks, and not the other way around.
Because of this, Specialized has lightened the damping across the board for each shock found on each model. This is what the ‘Rx Trail Tune’ refers to, with every shock going through the dyno before being tuned accordingly. This can involve anything as complex as a custom air can with a different sized negative chamber and a full damper re-valve, or the shock may be entirely off the shelf with no changes required. The RockShox Deluxe RT3 on the Stumpjumper Expert Carbon falls into the latter category, though it has had its air chambers modified with volume spacers to get the correct spring rate for the 140mm of rear travel.
Oh and if you’ve had a look at the new Stumpy range and wondered why there are no Öhlins forks or shocks, Specialized informed us that it is still continuing to work with the Swedish suspension manufacturer. For the 2019 Stumpjumper bikes though, it’s all Fox and RockShox.
Geometry – A Sum Of Its Parts
The geometry changes to the entire 2019 Stumpjumper line can be summarised thusly; they’re a little slacker in the head angle, shorter in the seat tube, and they have increased top tube lengths that are matched by shorter stems. Overall it’s a gentle modernisation of the Stumpjumper’s existing geometry, rather than being a radical departure of what’s already worked for Specialized up until now.
On the Stumpjumper 29er, the head angle has been kicked back by half a degree to 66.5°, and the reach on the medium test bike has grown from 413mm to 425mm. Those two changes combine to increase the front centre measurement (the distance between the BB and the front hub) by 20mm, and therefore the entire wheelbase has grown by the same amount. The chainstay length remains modest at 437mm, even with the huge increase in tyre clearance. Likewise the BB drop of 33mm is unchanged over the previous Stumpy 29.
I’ll go into the geometry in more detail later, but one thing I can say right now to anyone wrinkling their nose at the less-than-radical numbers – this bike is the perfect example that ride quality is made up of the sum of is parts, rather than being dictated by just one or two numbers on a screen. It rides incredibly well. But if you really must have enormously slacker-than-thou geometry, you’re exactly who Specialized had in mind when it created the Stumpjumper EVO, which features a 63.5° head angle and a reach range of 445-490mm. So go check that one out radboy.
While we’re on geometry though, there is adjustability built into the Stumpy’s chassis. Two steel inserts sit inside the shock yoke that captures the lower shock eyelet, and these can be flipped between high and low settings. The bike comes setup in the low setting and changing to the high setting will lift the BB by 6mm and steepen the head angle by half a degree. Part of this adjustability is due to the wheelsize flexibility of the Stumpy chassis, so you can adapt the BB height whether you’re running 2.3in or 3.0in wide tyres.
I won’t dwell too much on the build kit – the full spec list is down the bottom of this page for those who want to read it in detail. Across the board however, you’ll find all 2019 Stumpy models spec’d with 1x drivetrains and shorter 170mm crank arms, 780mm wide bars and a 40mm long stem (50mm on L & XL frame sizes). There’s a Butcher tyre up front and a Purgatory out back, both of which are equipped with Specialized’s reinforced GRID casing, a Gripton rubber compound, and a slightly optimistic 2.6in width that appears closer to other brand’s 2.4in and 2.5in tyres, though I didn’t get the chance to measure.
The Expert Carbon 29 here is adorned with a SRAM GX Eagle 1×12 drivetrain and Guide R brakes with a 200mm rotor up front for more stopping power. Wheels come from Roval in the form of Traverse Carbon 29s, which get 30mm wide hookless carbon rims and are now spec’d with 28x spokes front and rear (rather than the 24/28 spoke count used on last year’s wheels).
I was able to weigh my test bike, which came in at 13.21kg (29.1lbs) without pedals, but including the SWAT bottle cage and multi-tool.
Riding The 2019 Stumpjumper 29
Although I’ve just taken you through most of the key geometry and frame features of the new Stumpy, I should point out that our experience on the launch was not the same. Rather than a huge powerpoint presentation filled with videos, suspension graphs and stiffness charts, the Specialized team gave us a brief 40 minute chat about some of the prototyping they did for the new bikes and explained some of the goals that they set out to achieve. Then we just put our riding kit and got setup on the bikes to go riding. There were no geometry charts, and no discussion about spec – we didn’t even know what suspension travel the bikes had.
I actually quite liked this, and even as I was getting setup on the Expert Carbon 29 test bike, I deliberately avoided looking at the little stickers on the back of the Pike fork that would divulge such information like travel and offset. With three days ahead of us on the launch, there’d be plenty of time to chat about those specifics. But first, I wanted to ride the bike without any preconceptions.
For suspension setup, I set the rear shock up at 30% sag as recommended, and positioned the rebound damping exactly halfway at five out of ten clicks. Inside the rear shock are three Bottomless Tokens as stock, though I didn’t feel the need to change volume – the rear suspension is absolutely sublime out of the box. The fork was a different story though, as the O-ring made it clear I was still a good way off full travel after the first day of riding. I removed the single Bottomless Token, set the air pressure at 73psi to support my 72kg riding weight, and enjoyed a plusher and more linear feel to the travel for the second day’s riding. I set the rebound damping one click faster than halfway to give the front end a little more pop.
Not knowing the reach measurement, I would have sworn during those two days of riding that it was more than 425mm. The Stumpy feels generous in its cockpit size, with the 780mm riser bars giving the Goldilocks feel for my hand position. Even though the new shorter seat tubes mean you can size up if you wish, the Medium fit me so well that I wouldn’t be keen to give that up just for the sake of one theoretical number.
The stock Specialized saddle is comfy enough and I really like the new textured dropper post lever on the Command IRcc dropper post. Even when the heavens opened up on the second day of riding and we found ourselves trudging through cake-batter type mud (Spain – who would have thought?), I still had great feel and traction on the dropper paddle.
The post itself has a smooth and light action, with a less aggressive top-out than the current Command dropper post. However, my post developed an issue with the internal top-out bumper, which meant on the second day of riding the post was reluctant to push right to the top. Hopefully this is sorted for production bikes, as the existing Command dropper has been one of my favourite and most reliable dropper post choices for a while now. Though the new one shares a similar mechanical locking system, having that full 160mm of drop makes a huge difference to the bike’s descending confidence.
As for the Stumpy’s handling, the overall feel is one of balance and ease of use. It doesn’t feel big, but it motors along at pace over rough terrain with a tonne of stability. The longer front centre does help to push the front wheel out further ahead of you for increasing your footprint on the trail, though combined with the slightly steeper seat angle, your centre of gravity feels almost exactly in between the two wheels like a mid-engine sports car. In tighter trail scenarios, this balanced weight distribution gives you excellent awareness of the bike’s extremities, rather than wondering if the rear wheel is going to make the corner or not. The only issue I encountered was on sharper uphill switchbacks, where the tall-ish front end becomes more challenging to manage. Some experimentation with bar position and height could help offset this though.
On faster and wide-open descents however, the Stumpy feels confident, planted and easy to shift your weight around on depending on where traction is required. Despite riding on unfamiliar trails that were regularly loose, rocky and quite steep in sections, I had no troubles trusting the Stumpy to pull me through and out the other side.
This is the result of a few factors. Firstly, the suspension is excellent, and in my opinion, is one of the Stumpy’s best attributes. The new FSR platform has good small-bump sensitivity, but it’s the consistency of the spring rate through the first ¾ of the travel that offers such a predictable feel. It pedals efficiently providing you stay seated on the saddle, and there was no point where I found it necessary to use anything but the Open compression position on the Deluxe RCT3 shock.
The bike is certainly responsive, with good feedback through the pedals that gives the Stumpy a nice platform to push off of. It never feels doughy or dead, and that’s a testament to the work that’s gone into developing the frame’s kinematics in tandem with the shock spring and damper tune. To sum up the rear suspension performance, it just does what it’s meant to without you really having to think about it.
The 2.6in Specialized tyres must also be commended for their thoroughly impressive traction, with the new Gripton-equipped Butcher in particular having saved my bacon on several occasions. In fact, I can’t remember one moment where it actually broke traction. Combined with the supple DebonAir-equipped Pike fork, the front end of the Stumpy feels supremely confident for a long travel trail bike. I can see why Jared Graves will be racing this bike rather than a Stumpjumper EVO for the remainder of the 2018 EWS season.
I can’t say I found many situations to fault the Stumpy 29. The shifting on the GX Eagle drivetrain was a little off, and we saw a couple of journo’s rip open Eagle derailleur cages during the three days of riding. My assessment was that the chains on our test bikes were set up too long from the factory, as Eagle tends to be sensitive to chain length as well as B-tension.
Everything else worked without fault though, and I must say that I had a hard time trying to discover the limits of the bike. Even while chasing riders much faster and more talented than me, I could only get off the brakes and go quicker on the Stumpy – not once did I feel like I was pushing beyond its comfort zone, even though I was pushing outside of mine. Testament to the bike’s confidence-inspiring demeanor was the fact that I was taking off of bigger jumps and hitting much taller drop-offs than I would have attempted on my own. And I was having an absolute ball doing it too.
Though I ‘only’ racked up 75km worth of riding aboard the 29er Stumpy, getting the chance to ride it on completely new trails while being surrounded by faster and more talented riders was a great way to explore the limits of both the bike and my own riding skills. The Stumpy carried me through commendably, with its excellent suspension package, balanced weight distribution, and sticky tyres keeping me upright on a number of occasions where I should have been anything but.
While I’m keen to get both the regular Stumpy and short travel version in for a much longer term test on British soil, my early impression of this bike is one of balance and synergy. Not one component, geometry number or frame feature stands out from the rest. Instead, they all come together into one impressive package that is up there as one of the best all-round trail bikes I’ve ridden.
2019 Specialized Stumpjumper Expert 29
- Frame // FACT 11m Carbon Fibre, 140mm Travel
- Fork // RockShox Pike RC, DebonAir, 150mm Travel, 51mm Offset
- Shock // RockShox Deluxe RT3, RX Trail Tune, 210x50mm
- Hubs // Roval Traverse Carbon, 110x15mm Front & 148x12mm Rear
- Rims // Roval Traverse Carbon, 30mm Internal Rim Width, Tubeless Ready
- Tyres // Specialized Butcher GRID 2.6in Front & Purgatory GRID Rear
- Crankset // Truvativ Descendent, 30t X-Sync 2 Chainring, 170mm Arm Length
- Rear Mech // SRAM GX Eagle, 12-Speed
- Shifters // SRAM GX Eagle, 12-Speed
- Cassette // SRAM XG-1275 Eagle, 10-50t, 12-Speed
- Brakes // SRAM Guide R, 200mm Front & 180mm Rear Rotors
- Stem // Specialized Trail, Forged Alloy, 31.8mm Diameter, 40mm Length
- Bars // Specialized Trail, 7050 Alloy, 31.8mm Diameter, 27mm Rise, 780mm Wide
- Grips // Specialized Sip Grip Half-Waffle Lock-On
- Seatpost // Specialized Control IRcc, 34.9mm Diameter, 160mm Travel
- Saddle // Specialized Body Geometry Phenom Comp, 143mm Width
- Size Tested // Medium
- Sizes Available // Small, Medium, Large, X-Large
- Actual Weight // 13.21kg (29.06 lbs)
- RRP // £5,000
|Product:||Stumpjumper Expert Carbon 29|
|Tested:||by Wil Barrett for 3 days|