Specialized’s 2021 Stumpjumper Evo promises tantalising trail-domination

Specialized’s 2021 Stumpjumper Evo gets refined geometry with plenty of adjustability, six size options, four models and prices starting from £3,900 for the Comp and rising to £9,250 for the S-Works Carbon bike.

The new model is only offered in 29in wheels, unlike the outgoing Evo that could be bought with 27.5in or 29in hoops. However, there is a factory mullet option with a 29in front wheel and 27.5in rear, dubbed the LTD Carbon, which is fitted with a coil-sprung RockShox rear shock and ZEB fork.

Specialized assures us that its smallest S1 size bike with 29in wheels has a lower standover height and shorter seat tube length than the outgoing 650b S2. It now has 150mm of rear wheel travel.

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Other updates include increased SWAT – Specialized’s internal storage system – volume with an integrated water bottle and a SWAT steerer tube-hidden tool.

The bike’s also got adjustable geometry, thanks to a flip-chip on the Horst-link pivot, and replaceable headset cups.

Back in 2018, when the first Stumpjumper Evo was launched, it unchained the trail bike, offering a pedal-friendly mid-travel trail bike with truly progressive geometry. Unsurprisingly, the Stumpy Evo was well-received thanks to its truly modern take on traditional trail riding.

In 2019, a carbon version of the Stumpy Evo was launched and although it was only available in two sizes, it marked a continued dedication from the Big S to the Evo bike.

And that’s where the latest Stumpjumper Evo picks up the story; now a fully-fledged model of its own with a host of sizes and specs to choose from.

2021 Specialized Stumpjumper Evo frame details

Touted as the “ultimate trail bike”, Specialized says it's designed the Stumpy Evo to address the needs of the discerning modern trail rider head on. Its big-hitting trail bikes hope to do this in a few ways, one of which is the frame and its design elements.

The frame’s FACT 11M carbon construction is claimed to hit a Goldilocks sweet-spot between too stiff and too flexy, achieved by the Sidearm strut that asymmetrically – on the right-hand side – spans between the shock’s mounting point on the top tube and the linkage rocker pivot’s anchor on the seat tube.

Specialized says the Sidearm reduces twist and has been tuned to give the Stumpy Evo its feel, which it claims “unifies the frame from front to rear”.

The frames have also been built with specific riders' weights in mind to tune the feel, so someone who weighs 120kg riding an S6 will experience the same ride qualities as a 50kg rider on an S1.

Specialized calls this tech “Rider-First Engineered” and the information used to decide how much frame material is needed in its construction in specific areas is generated from hours of data acquisition, measuring forces through the frame backed up by hours of testing and riding.

The capacity of Specialized’s on-board down tube storage solution, dubbed SWAT, has increased in size by 15 per cent compared to the old Stumpy Evo. Included with the bike is a 625ml flexible and shaped SWAT bottle that can be stashed inside the down tube, increasing on-board water capacity because there's also an external bottle cage.

If you’re not as thirsty as some, the SWAT bladder can be removed and replaced by tools, food or clothing.

Because the Stumpjumper Evo is a trail bike, weight is also a consideration. Specialized says its S4 frame – including shock and all hardware – weighs 2,750g.

We weren’t able to weigh a frameset, but our full-build Stumpjumper Evo S-Works model without pedals in S4 weighs 13.92kg.

There’s an integrated chainstay protector with moulded ridges designed to help quieten chainslap. The frame also has an integrated down tube protector and internally-routed cables from front to back, with internal cable guides to make routing easy.

2021 Specialized Stumpjumper Evo suspension

With 150mm of rear wheel travel, Specialized claims the Stumpy Evo’s got great bottom-out resistance while being mega compliant over smaller bumps, and somehow managing to pedal well and eat speed-sapping hits for breakfast.

It's done this by using a relatively progressive suspension leverage rate with an almost perfectly linear increase in progression, getting harder as the bike compresses through its travel.

Specialized is confident its leverage rate is progressive enough for the typically linear spring rate of a coil shock, as specced to its LTD mullet Evo.

The bike’s axle path has been tuned to have a small portion of rearward travel – from between full extension to 42mm into its travel. This, it hopes, should help the bike handle square-edged hits without losing as much speed as bikes with vertical or entirely forward axle paths.

2021 Specialized Stumpjumper Evo geometry and sizing

The Stumpjumper Evo is now offered in six sizes rather than just the two options seen on the older model. The sizing is based around riding style (hence the ‘S’) rather than inseam measurements because the bike’s standover heights and seat tube lengths from S1 to S6 only grow by 37mm and 80mm respectively. The Evo, therefore, is a low but long bike.

The S1 size is equivalent to an extra-small bike, while the S6 is the equivalent to an extra-extra-large bike, but Specialized says that depending on how you like your bike to ride, whether that’s flicky and twitchy or stable and calm, you should be able to select a size above or below your equivalent one.

Its chainstay length is also size and setting dependant. The S1 to S4 frames have a shorter 438mm/443mm chainstay, while the S5 and S6 bikes have a 443mm/453mm chainstay length.

The Stumpjumper Evo’s geometry is adjustable, too.

Thanks to a flip chip on the Horst-link pivot, it’s possible to swap the bottom bracket (BB) between high and low settings that changes its height from 331mm up to 343mm, depending on which headset cup is fitted.

Swapping the BB height flip chip also changes the chainstay length from 438mm to 443mm for the S1 to S4 bikes and 448mm to 453mm for the S5 and S6 bikes.

Two separate headset cups – a slack or steep one that’s turned through 180 degrees to create the different settings and a neutral cup – give a range of head angles from 65.5 degrees to 63 degrees in its slackest setting.

There are six possible combinations of bottom bracket height adjustment and head angle adjustment, meaning the bike has six different geometry settings. The bike is set up in the factory setting when delivered, which uses the high bottom bracket and middle headset cup.

Standout figures for the S4 – the size large equivalent – in the factory setting include a 475mm reach, a 64.5-degree head-tube angle, 1,247mm wheelbase and 438mm chainstay. The effective seat-tube angle sits at 76.9 degrees.

For comparison, in its lowest and slackest setting, the S4’s reach is 468mm, the head angle is 63 degrees, the wheelbase is 1,261mm and the seat-tube angle 76.6 degrees.

2021 Specialized Stumpjumper Evo models and specifications

The 2021 Stumpjumper Evo is available in four levels.

The most affordable Comp Carbon, priced at £3,900, is specced with Fox’s 36 Float Rhythm fork, a DPX2 Performance rear shock and Shimano’s SLX 12-speed drivetrain, while the £9,250 S-Works Carbon model is specced with SRAM XX1 Eagle AXS and a Fox Factory 36 fork and DPX2 rear shock.

2021 Specialized Stumpjumper Evo S-Works Carbon

• Frame: FACT 11M carbon fibre, SWAT integration, geometry adjustment, 150mm travel
• Shock: Fox Float DPX2 Factory EVOL, Kashima coating, 3 position adjustment with open mode low-speed compression adjuster
• Fork: Fox Float 36 Factory, GRIP2, Kashima coating, 44mm offset, 160mm travel
• Groupset: SRAM XX1 Eagle AXS
• Brakes: SRAM Code RSC
• Wheels: Roval Traverse SL carbon, 30mm internal width on Roval Traverse SL hubs
• Tyres: Butcher GRID Trail, GRIPTON compound 2.3x29in (f), Eliminator GRID Trail, GRIPTON 2.3x29in
• Bar/stem: Roval Traverse SL Carbon / Deity Copperhead
• Seatpost: RockShox Reverb AXS
• Saddle: Specialized Bridge
• Price: £9,250

2021 Specialized Stumpjumper Evo LTD Carbon mixed wheels

• Frame: FACT 11M carbon fibre, SWAT integration, geometry adjustment, 150mm travel
• Shock: RockShox SuperDeluxe+ coil
• Fork: RockShox Zeb Select+, DebonAir, Charger 2.1 RC, 160mm travel
• Groupset: SRAM X01/GX Eagle mix
• Brakes: SRAM Code RS
• Wheels: TBC
• Tyres: Butcher GRID Trail, GRIPTON compound 2.3x29in (f), Eliminator GRID Trail, GRIPTON 2.3x27.5in
• Bar/stem: Specialized Trail / Deity Copperhead
• Seatpost: OneUp Dropper V2
• Saddle: Specialized Bridge
• Price: £6,000

2021 Specialized Stumpjumper Evo Expert Carbon

• Frame: FACT 11M carbon fibre, SWAT integration, geometry adjustment, 150mm travel
• Shock: Fox Float DPX2 Performance Elite EVOL, 3 position adjustment with open mode low-speed compression adjuster
• Fork: Fox Float 36 Performance Elite, GRIP2, 44mm offset, 160mm travel
• Groupset: SRAM X01/GX Eagle mix
• Brakes: SRAM Code RS
• Wheels: Roval Traverse 29 Alloy rims on Roval hubs
• Tyres: Butcher GRID Trail, GRIPTON compound 2.3x29in (f), Eliminator GRID Trail, GRIPTON 2.3x29in
• Bar/stem: Specialized Trail / Specialized Trail Alloy
• Seatpost: X-Fusion Manic
• Saddle: Specialized Bridge
• Price: £5,000

2021 Specialized Stumpjumper Evo Comp Carbon

• Frame: FACT 11M carbon fibre, SWAT integration, geometry adjustment, 150mm travel
• Shock: Fox Float DPX2 Performance EVOL, 3 position adjustment
• Fork: Fox Float 36 Rhythm, GRIP, 44mm offset, 160mm travel
• Groupset: Shimano SLX 12-speed
• Brakes: Shimano SLX
• Wheels: Roval 29 rims on Shimano hubs
• Tyres: Butcher GRID Trail, GRIPTON compound 2.3x29in (f), Eliminator GRID Trail, GRIPTON 2.3x29in
• Bar/stem: Specialized Alloy / Specialized Trail Alloy
• Seatpost:X-Fusion Manic
• Saddle: Specialized Bridge
• Price: £3,900