Specialized Stumpjumper Comp Alloy review

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 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.

The S-sizing means you can pick a bigger frame for a more stable ride or a smaller one for flickability.

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).

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.

SRAM takes care of shifting and stopping with its NX Eagle 12-speed drivetrain – with 11-50t cassette – and G2 R four-piston brakes with a 200mm front rotor and 180mm rear.

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.

Comfort was further enhanced by the smooth but massively supportive suspension, which absorbs trail chatter well and creates plenty of traction on rougher terrain.

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.

It does have limits, but these are only reached once you start hitting much steeper or faster trails suited to enduro and downhill bikes.

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.