Cortex GX Eagle AXS

Short travel 29er

£3,949.00

Fast and agile, Cortex is a trail riding, down-country, all terrain mountain bike for seriously epic days out. It ...

Cortex GX Eagle AXS

Photos for illustration purposes. Please check the bike spec for detailed component listings.

Cortex GX Eagle AXS

Short travel 29er

£3,949

Fast and agile short travel full suspension 29er mountain bike with SRAM GX Eagle AXS for precision wireless shifting, Rockshox Pike Ultimate fork and Deluxe Select+ rear shock.

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Buy Now. Be riding in 5 days.

Cortex GX Eagle AXS

Short travel 29er

£3,949

Fast and agile short travel full suspension 29er mountain bike with SRAM GX Eagle AXS for precision wireless shifting, Rockshox Pike Ultimate fork and Deluxe Select+ rear shock.

Buy Now. Be riding in 5 days.

  • Please select

  • Customise

    Every Sonder bike is built to order so tell us exactly how you want it. Make any changes you want from the standard build and when you’re done, just hit “Add to bag” at the bottom of the page.

    Accessories

  • Handlebar

    • Sonder Aspect Riser 780mm

    • Sonder Aspect Riser [OEM]

      In general riser bars tend to be wider than flat bars and may have slightly more flex to give a more forgiving ride. As you go into descents and your arms drop below your knees the additional height gained on your front end will help you take control of the steep descents.

      That said you can get all bar types in a range of widths and stiffnesses and front end height can be adjusted with spacers like our Sonder Rings, so sometimes you just have to ignore the mumbojumbo and make your call on style and personal preference and there is nothing wrong with that.

    • Sonder Aspect Flat 720mm

      +£0

    • Sonder Aspect Flat [OEM]

      Flat bars help you keep the front end of your bike low, allowing you to get the weight over your front wheel when climbing and giving you more control in cornering.

      Our flats have a 5˚ rise so technically we should call them flatish, but if you really need them to be totally flat just rotate in the stem clamp!

    Saddle

    • Sonder Abode Black / 138

    • Sonder Abode [OEM]

      High density foam padding over a plastic base provides comfort and longevity. A v-shaped split at the rear of the saddle allows flex as you are riding, increasing shock absorbancy and reducing pressure on the spot between your sit bones.

      Scooped up at the back with a slight rise towards the nose the longitudinal profile provides a cupped, craddled seating position, a timeless, proven design for distance on and off the road or climbing in the mountains.

      Stainless steel rails give 50 mm of forward and back adjustment to help you find your sweet spot.

      All our Sonder bikes come with Abode fitted as standard.

    • Sonder Abode Black / 158

    • Sonder Abode [OEM]

      High density foam padding over a plastic base provides comfort and longevity. A v-shaped split at the rear of the saddle allows flex as you are riding, increasing shock absorbancy and reducing pressure on the spot between your sit bones.

      Scooped up at the back with a slight rise towards the nose the longitudinal profile provides a cupped, craddled seating position, a timeless, proven design for distance on and off the road or climbing in the mountains.

      Stainless steel rails give 50 mm of forward and back adjustment to help you find your sweet spot.

      All our Sonder bikes come with Abode fitted as standard.

    • Sonder Zone 133 / Black

      +£29.99

    • Sonder Zone [OEM]

      The Zone is designed for maximum pedalling efficiency and comfort on longer rides, whether on road or off it.

      • Chromoly rails with suspension system
      • Cut-out shape relieves pressure
      • High density foam seat for comfort

      We’ve selected a flat saddle profile that’s long enough to allow for lots of micro-adjustments to your riding position over the course of a full day on the bike. The nose width allows you to move forward over the pedals on climbs and sprints, and a tapered back enables you to get behind the saddle easily for switchback descents or technical off-road sections.

      We’ve chosen a nylon fibre saddle base to provide a stiff and stable pedalling platform for a low overall weight. This base is connected to the chromoly rails using a patented suspension system that reduces road buzz and improves comfort without compromising on support.

      High density foam stays comfortable for longer, adding to the saddle’s supportive platform. And a long central cut-out in the middle of the Zone relieves pressure on the perineum, allowing you to ride for longer.

    • Sonder Kura

      +£34.99

    • Sonder Kura [OEM]

      Adventure cycling is diverse; in the course of a single trip you can find km's of asphalt, traverse rutted grasslands, weave through thickly forest singletrack, climb loose gravel track or descend steep rocky trails.

      It is unlikely you are going to find a single saddle position for all of this terrain. With this in mind Kura has a flat longitudinal profile with a gentle lateral curvature to give an extended saddle area, allowing you to position yourself around the saddle as you move between road, downhill, and climbing.

      The honeycomb base reduces weight whilst still providing structure and support that adapts and flexes with your motion.

      Titanium rails giving 50 mm of forward and back adjustment to help you find your sweet spot. Titanium is more forgiving than steel so provides a little more comfort.

      Slightly wider than our Adobe saddle, it may provide additional comfort for riders with wider sit bones.

    • Brooks Cambium C17 Saddle / All Weather / Black

      +£94.99

    • Brooks Cambium C17 Saddle [OEM] / All Weather / Black
    • Brooks B17 Saddle Standard / Black

      +£109.99

    • Brooks B17 Saddle

      Manufactured in the UK, a tough 5mm thick leather top is stretched from a thin metal cantle plate at the rear, over the rails to the nose piece and secured by rivets. This durable leather top eventually wears to the shape of the user’s ‘sit bones’ for a superior riding experience. With the right leather-care a Brooks saddle can easily last a lifetime of riding.

      It may seem counterintuitive, but firm and less cushioned saddles are proven to reduce friction while cycling which protects against chafing and rubbing. Should the hammock-like design of the saddle start to sag too much, the leather can be re-tensioned by tightening a bolt in the nose piece.

    Seatpost

    • X-Fusion Manic Drop Seatpost and Lever 31.6mm / 125mm

    • X-Fusion Manic Drop Seatpost and Lever

      The X-Fusion Manic Dropper has been designed to work well across cross-country, trail, all mountain and enduro riding.

      It works on a simple design. Inside you’ll find a closed cartridge that is both sealed and designed to be easily removable from the rest of the post. Simple construction aside, the action of this post feels super-smooth and silky.

    • RockShox Reverb / 125mm Drop / 31.6 x 390mm

      +£174.99

    • RockShox Reverb / 125mm Drop / 31.6 x 390mm

      The RockShox Reverb provides effortless actuation and increased reliability featuring new Vent Valve Technology.

      With reduced overall post lengths and new travel options, riders of all shapes and sizes benefit from more travel than ever before. The Reverb Stealth is just really, really reliable at simply going up and down.

    • RockShox Reverb / 150mm Drop / 31.6 x 440mm

      +£174.99

    • RockShox Reverb / 150mm Drop / 31.6 x 440mm

      The RockShox Reverb provides effortless actuation and increased reliability featuring new Vent Valve Technology.

      With reduced overall post lengths and new travel options, riders of all shapes and sizes benefit from more travel than ever before. The Reverb Stealth is just really, really reliable at simply going up and down.

  • Forks

    • RockShox Pike Ultimate RCT3 29er / 130mm [OEM]

    • RockShox Pike Ultimate RCT3
    • Cane Creek Helm MK2 Air / 29 / 130mm 130mm

      +£149.99

    • Cane Creek Helm MK2 Air / 29 / 130mm

    Shock

    • Rockshox Deluxe Select+ / 190x45

    • Rockshox Deluxe Select+ / 190x45
    • Cane Creek DBair IL 190 / 45

      +£114.99

    • Cane Creek DBair IL
  • Tubes

    • WTB Inner Tube 29 / 1.9-2.3

    • WTB [OEM] Inner Tube

      Never one to be stranded roadside; Prudence states that you should always have a spare at hand even for your faithful tubeless set up, and who are we to argue with Prudence.

    • Tubeless Tyre Upgrade and Setup

      +£44.99

    • Tubeless Tyre Upgrade and Setup

      Go tubeless

  • Pedals

    • No Pedals (none)

    • No Pedals
    • Sonder Reko

      +£50.99

    • Sonder Reko

      The Reko are lightweight SPD pedals designed gravel riding and cross-country mountain biking over longer distances.

      The Reko's platform-free design reduces the overall weight of the pedals to 145g per pedal for lighter, faster riding. Double-sided SPD bindings are easy to clip in and out of and their compact design means they're less likely to clog with muck on filthy winter rides.

      The clip-in design improves the efficiency of your pedal strokes, saving energy on long rides and improving power transfer on climbs, and gives you more control of the back end of the bike.

    • Sonder Jekyll Black

      +£59.99

    • Sonder Jekyll

      Jekyll is two faced; SPD's and flats all in one, multi-purpose mtb touring pedals.

      Jekyll gives you the freedom to ride with normal shoes or with cleats. Jekyll combines a single sided SPD mechanism with a flat pedal body with grip pins on the other. They are ideal for riders who switch frequently from the daily commute to nipping down to the local shop for a pint of milk in their loafers.

      The flat side has 8 replaceable grip pins, 4 mm long, they provide grip in all conditions. When you are ready to get your power on the cleats are just a half rotation away - no swapping your pedals out.

      Jekyll also comes provided with Sonder 'SH-51 style' cleats.

    • Sonder Slingshot Black

      +£59.99

    • Sonder Slingshot

      The wide platform Slingshot pedal is designed to provide the support, control and confidence you need for a variety of riding, whether on trail, gravel or road.

      • Wide 87x90 platform made from 6061 aluminium
      • Double-sided adjustable SPD clips
      • Chromoly axle with sealed bearings

      The Slingshot's wide foot platform provides plenty of support to the foot for more comfortable pedalling over long distances, reducing hot-spots. This additional foot support also gives you greater control of the rear end of the bike on tight turns or technical trail.

      If you're using the Slingshot for mountain biking, the pedal's wide surface gives you a platform to stand on unclipped, ready to bail out if needed, on heart rate-quickening sketchy sections.

      With double-sided SPD clips and a large pedal area, the Slingshot is easy to clip in and out of in a hurry. A clipless system provides greater pedalling efficiency when climbing and more control when descending.

    • Sonder Distortion

      +£54.99

    • Sonder Distortion

      Sonder Distortion is a tough, solid, high performance flat pedal that won’t let you down. These are our team favourites and the pedal that designer Neil Sutton raves about. Pedals that equal the best, it's a large platform, thin profile pedal designed to be ridden hard in the worst conditions.

      A CNC-machined, light and durable 6061 aluminium body takes use and abuse day-in, day-out. The Cromoly axle gives durability and strength that you can depend on.

      Replaceable, double-sided (4.5/6.5 mm) steel pins are more than capable enough to take a beating on the trails without leaving you threading out the remnants with your pliers at the end of the day. Let’s face it, who wants that after a day round the trail?

    • Sonder Torque Black

      +£29.99

    • Sonder Torque
  • Bottle cages

    • No Bottle Cages (none)

    • No Bottle Cages
    • Sonder Sideblade Black / Left Entry

      +£5.99

    • Sonder Sideblade

      The Sideblade bottle cage not only gives your water bottle a lovely, secure hug, but its side loading system makes it easier to access when you need a drink, making staying hydrated a joy even when you've got a load of frame bags to work around!

      The Side blade is geared at letting you get to your water when you've got a bike packed up with frame bags, this means that it's also ideal for compact and full-sus frames where a standard loading bottle cage system just won't fit, you can choose which side you'd like to access your bottle by with a twist of the cage in the mount before your ride.

      Made of polycarbonate, the Sideblade is also super light and super duper tough - hooray!

    • Sonder Sideblade Black / PAIR

      +£7.99

    • Sonder Sideblade

      The Sideblade bottle cage not only gives your water bottle a lovely, secure hug, but its side loading system makes it easier to access when you need a drink, making staying hydrated a joy even when you've got a load of frame bags to work around!

      The Side blade is geared at letting you get to your water when you've got a bike packed up with frame bags, this means that it's also ideal for compact and full-sus frames where a standard loading bottle cage system just won't fit, you can choose which side you'd like to access your bottle by with a twist of the cage in the mount before your ride.

      Made of polycarbonate, the Sideblade is also super light and super duper tough - hooray!

    • Sonder Sideblade Black / Right Entry

      +£5.99

    • Sonder Sideblade

      The Sideblade bottle cage not only gives your water bottle a lovely, secure hug, but its side loading system makes it easier to access when you need a drink, making staying hydrated a joy even when you've got a load of frame bags to work around!

      The Side blade is geared at letting you get to your water when you've got a bike packed up with frame bags, this means that it's also ideal for compact and full-sus frames where a standard loading bottle cage system just won't fit, you can choose which side you'd like to access your bottle by with a twist of the cage in the mount before your ride.

      Made of polycarbonate, the Sideblade is also super light and super duper tough - hooray!

    Lights

    • No Lights (none)

    • No Lights

      -

    • Phase / 400

      +£19.99

    • Phase / 400

      The Phase 400 is our lightweight, yet durable, rechargeable bike light for a midweek evening blast on the bike.

      • 5 lighting modes and a 200m beam distance
      • Versatile: can be attached to handlebar, helmet or cockpit mount
      • Rechargeable Li-ion battery, with micro-USB cable

      Say hello to our sleek, new bike light range: they’re light, durable and rechargeable (and they say hi back). At just 123g, the Phase 400 is the final tool you need to make the most of evening rides. With 400 lumens and >200m beam distance, a Phase bike light will keep you company and confident on your dusk rides.

      The Phase 400 has been made with the roadie in mind: whether you’re on a family ride, a mid-week spin or your daily commute to work, you’re going to need an all-round bike light for the incoming dark evenings. But don’t worry if you end up on a canal path or a gravel track, this rechargeable light will suit you just fine for a short jaunt off-road.

      Flick between 5 lighting modes: high, mid, low, SOS and strobe. The Phase 400 has a maximum battery life of 8 hours and 20 minutes in low mode, so in the case of a surprise night-time emergency, you’re sorted. The 80-degree beam angle ensures you can see and be seen.

      We’ve added in some nifty features, including memory lighting. The light will remember the most recently used mode and default to it the next time you head out on your bike. The Phase 400 is compatible with a handlebar mount (included), a cockpit mount and a helmet mount. It also conveniently charges with a versatile micro-USB cable.

    • Phase / 800

      +£24.99

    • Phase / 800

      As the Phase 800 is especially designed for easy-going gravel paths, canals, and short singletrack trails, it is perfectly suited to the gravel rider. The 85-degree beam angle means you can see the journey ahead, as well as be seen by oncoming traffic or the local gravel gang.

      • >200m beam distance for dusk riding
      • Up to 18 hours of battery life
      • Memory lighting: the light defaults to the most recently used mode upon restarting

      The light boasts 5 modes: high, mid, low, pulse and strobe. In high mode, the Phase 800 lasts 1hr20mins – just enough time for your local mid-week, pre-dinner loop. On the other end of the scale, the 100-lumen pulse mode lasts over 18 hours! No matter your journey, Phase 800 can adapt to your trail.

      It’s got good memory too: the Phase 800 remembers your most recently used mode and defaults to it the next time you turn it on. Once you’ve finished shredding up the local gravel, don’t forget to recharge your light. It just needs a handy micro-USB cable to be ready for when you’re next raring to ride.

    • Boson

      +£29.99

    • Boson

      A powerful bike light with tough aluminium shell suitable for mountain biking and road biking. Boson is small and compact with a Li-ion rechargeable battery and a Micro USB port.

      Boson has 5 lighting modes which are cycled through (excuse the pun) with a single illuminated switch. High power pumps out 850 lumens making even the darkest commute a tunnel of light. Turn it down to medium power and you still have 320 lumens to play with - more than enough for negotiating un-lit cycle ways and paths.

      If you want to be seen rather than see where you are going switch out to the 6 or 3 Hz flashing modes. Bright enough to be seen even during daylight hours, it really comes into its own during the hours of twilight and dusk.

      A mounting bracket is included (fits 18 - 36 mm bars and no special tools needed). Once attached Boson can be fixed or removed with ease. It allows 360 degree rotation for complete control over your beam of light; the textured lens projects a smooth wide beam ideal for nocturnal riding.

      Note: Boson doesn’t take a "standard" 18650 battery - the battery has both anode and cathode at the same end. Do not switch on Boson during charging as it could damage the battery.

    • Hadron

      +£69.99

    • Hadron

      At a whopping 1,800 lumens, the Hadron shines like two twin suns on the front of your bars, allowing you to ride at daytime speeds long after the light fails.

      • Max power of 1,800 lumens with a wide beam angle
      • 6 different lighting modes to tailor to your riding
      • Remote control for swapping between modes at speed

      The Hadron uses twin Cree LEDs to provide a wide, bright beam that stretches well over 200m. This provides a ridiculous amount of night-time visibility so you can tackle tight and twisty singletrack at speed. It also comes with an optional remote control, allowing you to easily swap between lighting modes without needing to take your hands off the brake levers.


      With 6 different lighting modes, the Hadron’s brightness can be effectively tailored to your ride length, terrain and light levels. The lowest brightness Pulse mode runs for a massive 50 hours If you need to save battery on the roads or smoother sections. Plus, the twin bulbs are much more energy efficient than single bulb set-ups.


      The Hadron is housed in a durable 6063 alloy casing to protect your light from crash damage and an IPX6 rating is sufficiently waterproof for all-weather riding. An output jack on the Hadron means you can also use its large 6,700mAh lithium ion battery to charge your GPS or phone if you find yourself out of juice on mid-trip.

    Mudguards

    • No Mudguards (none)

    • No Mudguards
    • Sonder Fender Front MTB

      +£4.99

    • Sonder Fender

      The Sonder Front Fender protects you from excessive mud splatter on wet, mucky trails. These lightweight plastic mudguards don’t require any special fixings on your bike and can be strapped straight onto your forks with 4 cable ties (supplied).

      Made from durable polypropylene, if the Fender does meet its end, it can be easily recycled by most councils or at your local recycling centres.

Initial Price
£3,949
Frame
Cortex GX Eagle AXS
Size
Colour
Extras
£0
Total Price
£3,949
Description

Fast and agile, Cortex is a trail riding, down-country, all terrain mountain bike for seriously epic days out. It comes alive on long technical descents with 120 mm rear travel, big wheels and a stiff responsive frame.

With bang up to date geometry, Cortex is confidence inspiring with a playful character. Stand up and mash on the pedals out of turns, manual sections of trail and pop off tree stumps, rocks and roots. Smash out short and loose technical climbs, flat out descents and tight techy singletrack sections. The harder you push the bigger you grin.

..Read more

At a glance

  • SRAM GX Eagle AXS 12-speed groupset
  • Rockshox Pike Ultimate fork
  • Rockshox Deluxe Select+ shock
  • Sonder Alpha 29" wheelset

Cortex frameset is hand-welded from 6061 double butted aluminium with a tapered ovalised top-tube and large section down-tube for a stiff chassis with just enough compliance to get you out of trouble. 66 head angle, 74.5 seat tube angle, 40 mm bottom bracket drop and a 465 mm reach (size large). Cortex’s dialed in geometry and 2.6" tyre clearance offers a comfortable and efficient climbing position for big miles and a stable, spirited platform for smashing up descents.

GX Eagle AXS

GX Eagle AXS combines the proven GX Eagle groupset with SRAM®’s wireless shifting technology. Customisable via SRAM®’s AXS smartphone app, it shifts precisely and instantly every time, eliminating cable stretch completely. It also leaves your bars nice and clean!

Sitting in the middle of SRAM®’s groupset hierarchy, GX Eagle AXS is the best groupset most of us would ever need, using a 12-speed 10-52 tooth cassette.

Read less
Features

Up to Date Trail Bike Geometry

Trail bike Agility with Enduro bike stability, the Cortex has a confidence inspiring, stable and forgiving ride.

Metric Shock Standard

Designed around metric shock sizing standard, with lengthened shocks and shorter strokes that increase bushing overlap for more smooth, supple, sensitive and reactive suspension action.​

Horst link suspension design

The tried and tested Horst link suspension design allows the suspension to stay active when braking.​

Tyre Clearance

​Clearance for up to 29 x 2.6in tyres.

Internal Cable Routing

​Internal routing in the front triangle for clean lines.

Build Spec
Frameset
Frame:Cortex Frame | 6061 aluminium
Fork:RockShox Pike Ultimate | 130mm (travel)
Shock:RockShox Deluxe Select+ | 190 x 45
Headset:FSA Orbit C-40-ACB
Groupset
Shifters:SRAM GX Eagle AXS Trigger | 1x | 12-speed
Brakes:Sram Code R | Hydraulic | Direct mount
Rotors:Avid Centreline | 180mm (front), 160mm (rear) | 6-bolt
Rear derailleur:SRAM GX Eagle AXS | Long cage | 12-speed
Chainset:SRAM GX Eagle DUB Carbon | 170mm | 32t
Cassette:SRAM XG1275 Eagle | 10-52t | 12-speed
Chain:SRAM GX Eagle | 12-speed
Bottom bracket:SRAM DUB | BSA | 73mm
Wheelset
Wheels:Superstar Wheels | 29" | XD
Front tyre:Goodyear Newton MTF Trail Tubeless | 29 x 2.5" | Black
Rear tyre:Goodyear Newton MTR Trail Tubeless | 29 x 2.4" | Black
Tubes:WTB | 29 x 2.4-2.8"
Finishing kit
Handlebars:Sonder Aspect Riser | 78cm
Stem:Sonder Piskie | 35mm
Seatpost:X-Fusion Manic | 31.6mm | 150mm (drop)
Saddle:Sonder Abode | 138mm | Black
Grips:Sonder Clutch | Black
Weight
Frame:S: 1.97kg; M: 2.0kg; L: 2.1kg; XL: 2.14kg
Build:S: 12.4kg; M: 12.65kg; L: 13.8kg; XL: 13.9kg
Pedals not included with full builds
Geometry and Sizing

Sizing

It is important to get the right size bike, if the bike fits it will be faster, more comfortable, and easier to handle. You can also take into consideration the standover height to ensure you pick a bike that will be a good fit. If you measure your inside leg and ensure there is a minimum of an inch from the toptube to your crotch this will give you enough seatpost adjustment to find your optimum saddle height.

Generally we recommend:
Small: Riders between 5ft 2in and 5ft 7in
Medium: Riders between 5ft 6in and 5ft 10in
Large: Riders between 5ft 9in and 6ft 2in
X-Large: Riders of 6ft 2in +

Cortex

Size Small Medium Large X-Large
ST - Seat tube 400 425 465 485
TT - Top tube 587 608 636 658
HT - Head tube 100 105 115 125
HA - Head angle 66 66 66 66
SA - Seat angle 74.5 74.5 74.5 74.5
CS - Chainstay 442 445 447 450
BB - BB drop 40 40 40 40
FO - Fork offset 51 51 51 51
WB - Wheelbase 1169 1191 1220 1244
SO - Stand over TBC TBC TBC TBC
RE - Reach 420 440 465 485
SK - Stack 602 606 615 625
Tyre Diameter 755 755 755 755
Fork Axle to Crown 540 540 540 540
Frame Spec

Alloy 29er short travel full suspension trail bike 

Weight: S: 2.73kg; M: 2.91kg; L: 3.05kg; XL: 3.11kg
Hydroformed and custom butted alloy frame tubing
Internal cable routing
Rear Shock: Rockshox Deluxe Select+ 190 x 45mm
Horst link suspension layout
120mm rear travel; 130mm fork travel
Clearance for up to 29 x 2.6" wide tyres
73mm BSA threaded bracket shell
148 x 12mm rear thru-axle
31.6mm seat tube, 34.9mm clamp
Headset: IS42/28.6 | IS52/40
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