Specialized have released the full carbon 2021 Stumpjumper EVO in no fewer than six style-specific sizes, each with six geometry settings. This is not going to be the bike for people who don’t like making decisions; there are too many to make! However, for those who love a bit of pre-ride and mid-ride fettling, the ability to tailor the bike to suit the mood of the ride, or match the terrain of the day, this is an exciting possibility. Let us talk you through it.
2021 Specialized Stumpjumper EVO
The “Ultimate Trail Bike” is what Specialized are calling it. Why? Because of its insane adjustability, you should be able to set this bike up to ride any trail well. Before we get into the plethora geometrical iterations of the bike, let’s take a look at its out-of-the-box configuration.
The Factory Setting for the 2021 Stumpjumper EVO is based around a 29″ front wheel paired with a 29″ rear wheel. More on alternate arrangements later… Upfront, this trail bike gets a 160mm travel fork paired with 150mm rear wheel travel.
Six sizes are on offer from S1 to S6, equivalent to the “old-style” XS-XXL frame sizing nomenclature. Chainstay length measures in at 438mm for S1-S4, jumping up to 448mm for S5 and S6. Reach stretches from a compact 408mm for S1 right up to a very generous 528mm for S6.
Why so many sizing options? Specialized want riders to chose their size based on their riding style, not their inseam length alone. That means choosing a bike with the most appropriate reach to chainstay ratio for the type of riding you love best; be it off-the-brakes straight line bombing through the rough, or slow-speed technical trail riding requiring a little more finesse.
Take S3, for example – the medium frame, effectively. This may be your typical frame size choice, based on your overall height and inseam length. Specialized would encourage you to consider downsizing to the S2 if you want a quicker more nimble ride feel. On the other hand, if you want something a bit more stable at speed, opt for the S4 with its front-centre measurement.
Broadly speaking, at the smaller end, the shorter reach and wheelbase produce a more maneuverable bike. At the larger end, a longer chainstay, reach and wheelbase should make the bike feel more predictable and stable at speed.
Six Geometry Settings
Once you’ve chosen a size to suit your riding style, the geometry configuration for your new bike is (almost) endless. The 2021 Stumpjumper EVO let’s you choose from three possible head angles with the use of unique eccentric headset cups; slack, middle and steep. And two possible BB heights; low and high. That’s six different configurations, before we even consider mullet-ability.
The head angle can be tuned from its steepest at 65.5°, to its slackest at 63°. That is seriously slack for a 150mm trail bike. At the BB, drop it 7mm from 343mm to 436mm with the headset cup in steep mode. To get the biggest change to the BB height, drop it 7mm while switching the headset cup to slack mode, giving you a net drop of 13mm for S3.
Out-of -the-box, the EVO’s factory setting has the “high” BB setting with the headset cup set to middle. For S3 (or medium) that gives a BB drop of 35mm and a head angle of 64.5°.
The 2021 Stumpjumper EVO can also take a 27.5″ rear wheel, so you can run it mullet style. Take advantage of a fast-rolling wheel up front for trucking through the rough, paired with a more compact, nimble 27.5″ wheel at the rear. You’ll need a different, aftermarket shock link to run the mixed wheel size.
For the full information on the six geometrical configurations of the 2021 Specialized Stumpjumper, head to the Specialized website – they have six different geometry charts ready for you to pore over.
Stumpjumper EVO Suspension Tech
To give us an idea of the suspension qualities of the new Stumpjumper EVO, Specialized have given us its rear axle path and leverage curve, as compared to those of the Specialized Enduro bike.
As with the Enduro, the rear axle travels rearward throughout the first portion of the stroke, approaching around 3mm of rearward horizontal travel. It travels backwards ever so slightly further than the rear wheel of the Enduro, until they both hit ~40mm of rear wheel travel. The arc carved from there onward results in forward travel of the wheel of ~13mm to at the full 150mm travel.
This arc would translate to elongation of the bike’s rear end between its unloaded state and the SAG point, becoming a shortening of the rear end thereafter, and a resulting shorter wheelbase.
The new EVO’s leverage rate is derived from the Enduro’s progressive curve. Specialized say this is key to delivering small bump sensitivity, mid-stroke support, and compliant but controlled full travel. The graph shows a pronounced ramping up between 130mm and 150mm of rear wheel travel.
Specialized say this leverage rate makes it easier to tune the shock to match the kinematics.
The new Stumpjumper EVO utilizes a “sidearm” chassis. That’s an asymmetric strut that flows along the right hand side of the shock between the top tube and seat tube. Specialized say it’s an integral part of the EVO frame, minimizing twist to create a strong chassis.
They are very keen to communicate that while this carbon frame is stiff, they were certainly not out to create the stiffest chassis in the world, appreciating that a bit of compliance goes a long way to achieving a good ride feel.
The new Stumpjumper EVO gets the Specialized SWAT treatment with a storage space sat underneath the bottle cage. It’s 15% larger than what you’ll find on other Specialized bikes that feature SWAT. You should be able to get 22oz (625ml) of water in there using Specialized’s specially designed bladder (included).
Specialized claim a production painted S4 frame in its “ready to build” assembly weighs 2750g. That includes a Fox DPX2 Factory shock, all assembly hardware, link, carbon extension, molded downtube and chainstay protectors, axle and seat clamp.
Speaking of frame protection, the new Stumpy EVO gets a proprietary Specialized chain stay protector to keep the bike quiet when chain slap inevitably occurs. We note that it doesn’t quite run the full length of the chainstay leaving the area near the chainring looking a little vulnerable. We can’t tell whether the underside of the driveside seat stay also has frame protection.
Pricing & Availability
The 2021 Specialized Stumpjumper EVO is available at five price points from $4,099 for the entry-level EVO Comp build, up to an eye watering maximum of $9,899 for the top-end S-WORKS.
The Comp features a Fox Float DPX2 Performance shock, a Fox Float 36 Rythm fork with GRIP damper, Shimano SLX 4-piston brakes and 12 speed drivetrain.
The all-singing all-dancing S-WORKS build gets the DPX2 Factory shock, Fox 36 Factory fork with GRIP2 damper, SRAM Code RSC DH-spec stoppers, an electronic shifting SRAM AXS Eagle drivetrain with XX1 low-friction chain and Roval Traverse Carbon wheelset.
You can also pick up the S-WORKS EVO Frame alone for $2,999. For full info on pricing and availability, head to the Specialized website.