Specialized Stumpjumper 2021: First Look & Review

Words by David Hicks

on 13/10/2020 17:00:00

Sepcialized Stumpjumper 2021

The Specialized Stumpjumper needs no introduction - it has been a mainstay of mountain biking for almost forty years, and continues to keep on top of the latest trends as one of the most popular and desired bikes around for trail junkies. For 2021, the Stumpjumper's story is one of evolution rather than revolution, but those tweaks and updates to an already stellar platform put it right at the front of the pack when it comes to finding the ultimate all-round trail bike.

Last updated a few years ago with its striking sidearm frame design, the new Stumpjumper looks - visually, at least - pretty similar to its predecessor. But dig a little deeper and there's a slew of smart tech, refined kinematics, and flexible sizing & geometry with features drawn from both the Epic EVO and the newly-updated Stumpjumper EVO all bundled up in a 140mm front, 130mm rear travel, 29er trail bike.

The result of these changes is a singletrack flow finder that thrives in varied terrain and unlocks your potential on the trail, with the ability to climb like no full suspension trail bike before it - and shred the descent too.

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The backbone of the ride

The frame, the backbone of any bike, gets all the serious treatment when it comes to updates for the new Stumpjumper, and the carbon models in particular see the biggest changes. Take a closer look at the rear end of the back and you'll see something's missing - that's right, there's no pivot where the chainstay and seatstay meet on the new Stumpy.

Specialized realised that there was no mechanical pivot around the rear dropout, and by removing the pivot altogether they could ditch 55g of hardware and, thanks to some carbon wizardry, improve lateral chassis stiffness and precisely match the suspension kinematics to chassis stiffness. The result? The lightest, most efficient, control-enhacing suspension solution for a mid-travel trail bike that Specialized have ever made.

Specialized Stumpjumper 2021 carbon frame

With the rear pivot removed, the seatstays and chainstays have undergone a redesign with new shaping and a change in layup to create a flex zone along the seatstay. This section, above the brake mount, serves up 130mm of travel without the need for any rear end pivot hardware and stiffens up the rear end, improving responsiveness making sure none of that power is wasted when it comes to pedalling uphill.

Elsewhere, the frame has been gone over with a fine tooth comb to make sure there's no lazy carbon fibre kicking around where it isn't needed. This has meant any unnecessary material has been removed, with tube shapes optimised for stiffness and weight - and it's the sidearm frame design which has been the big beneficiary.

Specialized Stumpjumper 2021 First Ride Review

The new frame sees the top tube and shock mount section designed together to make the best use of the material available, while the sidearm strut itself supports the shock link pivot to boost stiffness with a more direct connection between the front and rear ends of the frame.

Throw in some super smart carbon fibre technology and some more optimised layups, and the carbon frame weighs in at 2,240g; over 100g lighter than the previous Stumpjumper chassis.

While the carbon frames get top billing, Specialized have given their alloy models an overhaul too, and although they don't have the compliance for the Flexstay setup, they get the same great geometry, suspension tune, ride quality and S-Sizing as their carbon siblings.

Capable control

In search of the perfect all rounder, Specialized have also given the new Stumpy's suspension kinematics a fine tune. By tweaking kinematics, leverage curves, damping and spring rates, the new Stumpjumper is designed to deliver a highly controlled, responsive and precise ride that handles bump forces like a bike with much more travel.

So what does that mean in practice? With a progressive leverage rate and steep slope, you'll be using the travel where you need it, depending on the terrain - that means that you'll have a solid platform to pedal against through the mid-stroke but the bike will take bigger hits in its stride.

Specialized Stumpjumper 2021 first look

Here, the spring rate helps. Specialized have used a larger volume spring for a more gradual spring ramp which enables more usable travel in your day-to-day trail conditions, while still saving progression for those bottom-out hits. Compression and rebound damping have been refined too, to help achieve excellent pedaling performance without sacrificing bump performance.

The result of all the Rx Tune is a bike that feels lively and snappy to ride for the first two-thirds of travel but, thanks to the increasing spring rate, still has excellent management of bottoming out on big hits. The progressive damping catches those big impacts too, but because the rebound damping is lighter through the midstroke, it comes back quickly ready to handle the next impact.

Find your size

Last but certainly not least, this feast of trail goodness is topped with a healthy dollop of shred-friendly geometry and adjustability to add an extra layer of control and efficiency. With a low bottom bracket, slack 65 degree headtube and reduced fork offset, the Stumpy stays steady in the rough. At 76.5 degrees the seat tube angle is steep to optimise power transfer when climbing, while the short chainstays keep things flickable.

To match your bike to your style and terrain, the Stumpjumper has two forms of adjustment. A Flip Chip at the rear shock eye lets you drop the bottom bracket height by 7mm, and an adjustable headset cover - just like on the new Stumpy EVO - lets you adjust the headtube angle by half a degree.

The new Stumpjumper also switches to Specialized's S-Sizing which you might be familiar with from the Enduro and Stumpy EVO. Rather than basing your bike size on your inside leg, S-Sizing is based on what matters - your size and style.

With six sizes, all with similar headtube lengths and standover you can choose the size that best suits your riding. If you're looking for a more nimble bike, look for the lower S-Size numbers with a shorter reach and front center measurement. On the other hand, the larger S-Size numbers deliver more stability and a roomier ride.

First Ride Review

Luke, from Rutland Cycling's buying team, took the new Stumpy for a spin and shared his first impressions of the new ride.

On the face of it, I looked at the new Stumpjumper and thought �what's changed?� After closer inspection and putting it through its paces on the trails of Glentress, everything clicked.

For the test, I was riding an S4 size bike which would equate to a Large. The beauty with Specialized's �S� sizing is that depending on my riding style, I could size up or down, without having to worry about my inside leg measurement.

If I wanted a poppier, more playful bike, I could opt for the S3, or for something a little longer and more planted, I could even size up to the S5. The S4 however gave me a perfect mixture of the two; playful characteristics on the trail, but still confidence inspiring. For reference, I'm 6ft and would generally ride a large frame size.

Specialized Stumpjumper First Ride Review at Glentress

The location - Glentress Scotland; The conditions - wet, wet, wet. When I rocked up at the trail centre, the riding conditions weren't looking great, there had been heavy rain overnight and it wasn't looking like it was going to stop throughout our day of riding.

It was a long old climb to the top, with some technical 'black' climbs along the way. The thought of a steep rocky climb in the dry is enough to put some nervous thoughts in my head, but in the wet it was even more daunting. That being said, the bike ploughed through, nice and light thanks to the FACT 11m frame, fast rolling thanks to the 29� wheels, and the suspension was absolutely spot on, getting me to the top with relative ease.

Once at the top after a short rest to refuel, we descended on the black trail which merges into the red. I was wondering how a 140/130mm trail bike would take the rocky natural descents of the black trail, but the bike didn't once feel out of it's comfort zone, gliding over rocks/roots at some considerable speed.

It's not often that you get on a demo bike and It feels like one of your own, but this was definitely the case with the 2021 Stumpjumper. I would normally ride a 160mm 650b Enduro Bike, so moving to a shorter travel 29er was a new one for me. That being said, I would now choose a 29� wheeled bike every time, and I can definitely see why Specialized are pushing that platform. The bike definitely 'felt like home' throughout my day of riding and left me wanting more and more, the miserable weather had gone to the back of my mind and I just wanted to keep ripping.

So who is this bike for? I came away with a definite thought in my head of this bike being the ultimate trail bike. It didn't feel uncomfortable on technical trails, I can't see it having any issues at bikeparks, and is ideal for most of the trail centres around my local area.

Most people don't have the luxury of having a trail bike, enduro bike, and a downhill bike in their garage and if I had to pick one bike to do everything, it would have to be the Stumpjumper.

Stumpjumper EVO

Looking to get a little rowdier? The Stumpjumper EVO could be the bike for you. Building on the standard Stumpy's baseline, the EVO is designed specifically for those gnarlier trails. Find out more about it in our First Look blog and video here.

Specialized Stumpjumper 2021 Range

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