The latest iteration of the iconic Specialized Stumpjumper has been given the ‘longer, lower, slacker’ treatment and updated with Specialized’s S-Sizing, where seat tube lengths are kept short so you can choose a frame size based on reach instead. It looks like a brilliant step forward for the brand.
Specialized Stumpjumper Alloy Comp details
- No SWAT: Alloy Stumpjumpers don’t have the down tube SWAT (Storage, Water, Air, Tools) compartment of their pricier stablemates, but this bike gives you a similar parts spec to the carbon Stumpy Comp for £1,000 less.
- Hush-hush: The Specialized is seriously quiet on the descents thanks to its inbuilt chainstay protector and well-thought-out internal cable routing.
- Hydration station: There’s plenty of space inside the front triangle for a full-size water bottle, thanks to the cage bosses being mounted nice and low on the down tube.
Specialized Stumpjumper Alloy Comp frame, geometry and suspension details
While pricier Stumpys, such as the Expert, get a carbon fibre frame with a tweaked suspension design that relies on seatstay flex instead of a rear pivot, the Comp Alloy is aluminium and uses Spesh’s usual four-bar ‘FSR’ system with Horst-link pivot in front of the rear axle.
It forgoes the carbon bike’s down tube SWAT storage, but has the same geometry, 29in wheels and 130mm of rear travel, plus shares the single-sided ‘Sidearm’ strut that spans the top tube and seat tube shock mounts.
You get Boost axle spacing, a single bottle mount and ribbed chain-slap protection. The brake and gear lines are routed internally, and a 73mm threaded bottom bracket (BB) simplifies maintenance.
Thanks to a Horst-link pivot flip-chip, geometry is adjustable. My S4 test bike had a diminutive 425mm seat tube, paired with a roomy 475mm reach and 615mm effective top tube length (in the ‘low’ setting).
|Seat angle (degrees) low/high||77.7/78.2||77.7/78.2||77.5/77.9||77.2/77.7||77/77.5||76.9/77.3|
|Head angle (degrees) low/high||65/65.5||65/65.5||65/65.5||65/65.5||65/65.5||65/65.5|
|Chainstay (mm) low/high||444/440||444/440||444/440||444/440||454/450||454/450|
|Seat tube (mm) low/high||385/385||385/385||405/405||425/425||445/445||465/465|
|Top tube (mm)||545||563||586||615||643||676|
|Head tube (mm)||100||100||110||120||130||140|
|Fork offset (mm)||44||44||44||44||44||44|
|Trail (mm) low/high||126/122||126/122||126/122||126/122||126/122||126/122|
|Bottom bracket drop (mm) low/high||47/40||42/35||42/35||42/35||42/35||42/35|
|Bottom bracket height (mm) low/high||327/334||332/339||332/339||332/339||332/339||332/339|
|Wheelbase (mm) low/high||1168/1164||1188/1184||1212/1208||1241/1237||1280/1276||1315/1311|
|Standover (mm) low/high||742/742||742/742||750/750||753/753||777/777||784/784|
|Stack (mm) low/high||618/614||613/609||623/618||631/627||639/640||649/644|
|Reach (mm) low/high||410/416||430/435||450/455||475/480||500/505||530/535|
Combine these with the 1,241mm wheelbase, 444mm chainstays, 65-degree head angle and 77.2-degree seat tube angle, and the high-speed potential is clear.
Its 130mm of travel has been tuned to perform on any kind of trail thanks to its progression, where the first part of its travel is soft and supple and the latter portion stiffer to resist bottom outs.
Specialized Stumpjumper Alloy Comp specifications
With parts from a host of big names, the Comp Alloy is good value for money.
Up front is Fox’s 140mm travel 34 Rhythm fork with GRIP damper that features external rebound damping adjustment and a progressive compression lockout dial.
The FSR suspension is damped by Fox’s Float DPS Performance rear shock, also with external rebound adjustment and a three-position compression adjuster.
Specialized provides most of the rest of the kit, including the bar, stem and saddle, plus Roval wheels wrapped in tubeless-ready Butcher and Purgatory tyres. An X-Fusion Manic dropper post caps off the build.
Specialized Stumpjumper Alloy Comp ride impressions
Whether you’re pointing the Stumpy up or downhill, it feels remarkably calm and composed, with its geometry, suspension and components working in seamless harmony. This makes it a pleasure to ride all day long.
On seated climbs, the steep 77-degree seat tube angle puts your hips over the BB for comfortable pedalling.
The general seated position was well-suited to long days in the saddle, too. This meant I didn’t have too much weight through my hands and there was no front wheel lift or steering vagueness on steeper climbs.
I didn’t need to compensate for the geometry at all, and generating grip was intuitive and easy, not needing massive weight shifts or energy-sapping changes in body position.
It’s nice and progressive, so doesn’t sag deep into its travel on steep ascents and also resisted bottoming out as I rode over deeper and wider holes. This reduced the ‘nodding’ feeling bikes with softer or less supportive rear ends can suffer from.
There’s some pedalling bob with the shock in its ‘open’ position, but not enough to hinder progress.
Flicking the blue lever to ‘climb’ mode eliminates unwanted movement, but at the loss of some grip, so I left it in the open position for the duration of the test period.
On the downhills, the bike’s composure makes it a hoot to razz around manmade trail centre loops, off-piste singletrack and epic all-day cross-country routes alike.
The slack and long – for a trail bike – geometry means it is confidence-inspiring on the downs and combined with the powerful SRAM G2 brakes, I was able to push the Stumpy well beyond my expectations of what a 130mm-travel bike should be able to handle.
Its suspension was super poppy and worked well no matter how hard or fast I was riding, too. When cruising down a trail, it had plenty of small bump sensitivity to improve comfort and grip, but also offered brilliant amounts of support halfway through the travel.
This meant I could pump and accelerate through holes without the bike feeling soft and wallowing. Bottom-out resistance was also good, especially when riding harder and faster.
I found the bottleneck in performance wasn’t down to its geometry, but the flexy-when-pushed Fox 34 fork.
This tended to tuck or twist when loaded up in sharp turns with steep run-ins, and its simple GRIP damper struggled to provide enough mid-stroke support unless I ran higher spring rates than recommended.
Upgrading to a 150mm-travel Fox 36 would unlock a whole lot more potential and make this excellent generalist even more capable.
That’s not to say it performed badly, in fact, quite the opposite was true. It was really intuitive to ride thanks to the great relationship between hands and feet that made me feel like I was ‘in’ the bike rather than ‘on’ it.
The Specialized Butcher and Eliminator combination were great on trail centre style runs regardless of the weather, but did tend to come unstuck on boggier terrain, although that was expected given their tread pattern.
The Code G2 brakes performed well and offer good levels of stopping power and I was impressed with the comfort offered by the Specialized Bridge saddle and own-brand grips.
Specialized Stumpjumper Alloy Comp bottom line
Overall, the Stumpjumper Alloy Comp rides impressively well, even when compared to lighter, more expensive bikes with flashier specs.
It’s good value for money, too, and the seriously capable frame means that a few choice component upgrades down the line would help unlock new levels of performance.
How we tested
We put four do-it-all full-sus trail bikes, at the super competitive price point of £3,000, to the test on our local trails to find out which is the best you can buy right now.
Trail bikes are designed to handle everything from bridleway bashing to the odd uplift day, but categorising a trail bike by its geometry or suspension travel is becoming harder because bikes are getting lower, longer and slacker with more squish.
Generally, though, you should expect 130mm to 150mm of travel, plenty of standover room, a decent reach (the horizontal distance from bottom bracket to head tube, which affects how a bike feels when stood up on the pedals) and a stable head angle, between 64 and 66.5 degrees.
Also on test
|Price||EUR €2999.00GBP £2500.00USD $3500.00|
|Weight||14.96kg (S4) – without pedals|
|Available sizes||S1, S2, S3, S4, S5, S6|
|Tyres||Specialized Butcher GRID GRIPTON 29x2.3in (f), Specialized Purgatory GRID GRIPTON 29x2.3in (r)|
|Shifter||SRAM NX Eagle|
|Seatpost||X-Fusion Manic, 170mm|
|Saddle||Specialized Bridge Comp|
|Rear Shocks||Fox Float DPS Performance Rx Trail Tune|
|Rear derailleur||SRAM NX Eagle (1x12)|
|Bottom bracket||SRAM DUB|
|Frame||Aluminium alloy, 130mm (5.1in) travel|
|Fork||Fox 34 Float Rhythm, 130mm (5.1in) travel|
|Cranks||SRAM NX Eagle, 30t|
|Chain||SRAM NX Eagle|
|Cassette||SRAM NX Eagle, 11-50t|
|Brakes||SRAM G2 R, 200/180mm rotors|