Buy Now

Cortex GX Eagle

Short travel 29er

€3.599,00

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

Cortex GX Eagle

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

Cortex GX Eagle

Short travel 29er

€3.599

Fast and agile short travel full suspension 29er mountain bike with SRAM GX Eagle drivetrain, Rockshox Revelation RC fork and Deluxe Select+ rear shock

Read more

Read more

Need help choosing a bike or technical advice?


  • Open a Live Chat
  • Pop into a store 7 days a week
  • Call a Sonder Customer Hero on 01773 417006
  • Email us at support@alpkit.com


Buy Now. We'll build yours in 5 - 10 days.

Buy Now

Cortex GX Eagle

Short travel 29er

€3.599

Fast and agile short travel full suspension 29er mountain bike with SRAM GX Eagle drivetrain, Rockshox Revelation RC fork and Deluxe Select+ rear shock

Buy Now. We'll build yours in 5 - 10 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.

    Saddle

    • Love Mud Abode / 138

    • Love Mud 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 Kura

      +€29,99

    • 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.

    • Sonder Zone 133 / Black

      +€27,49

    • 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.

    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 / 150mm Drop / 31.6 x 440mm

      +€199,99

    • 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.

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

      +€199,99

    • 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.

  • Forks

    • Rockshox Revelation RC 29 / 130mm

    • Rockshox Revelation RC
    • RockShox Pike Ultimate RCT3 29er / 130mm

      +€269,99

    • RockShox Pike Ultimate RCT3

    Shock

    • Rockshox Deluxe Select+ / 190x45

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

      +€129,99

    • Cane Creek DBair IL
  • Tubes

    • Tubeless Tyre Upgrade and Setup

      +€49,99

    • Tubeless Tyre Upgrade and Setup

      Go tubeless

  • Pedals

    • No Pedals (none)

    • No Pedals
    • Sonder Reko

      +€59,99

    • 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.

  • Bottle cages

    • No Bottle Cages (none)

    • No Bottle Cages

    Mudguards

    • No Mudguards (none)

    • No Mudguards
    • Sonder Fender Front MTB

      +€5,99

    • 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
€3.599
Frame
Cortex GX Eagle
Size
Colour
Extras
€0
Total Price
€3.599
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 12-speed groupset
  • Rockshox Revelation RC fork
  • Rockshox Deluxe Select+ shock
  • Sonder Nova 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.

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 Revelation RC / 130mm (travel)
Rear shock:Rockshox Deluxe Select+ / 190x45
Headset:FSA Orbit C-40-ACB
Groupset
Shifters:SRAM GX Eagle trigger / 1x / 12-speed / hydraulic
Brakes:SRAM G2 R / hydraulic / direct mount
Rotors:Avid Centreline / 180mm (front); 160mm (rear) / 6-bolt
Rear derailleur:SRAM GX Eagle / 12-speed / long cage
Chainset:SRAM GX Eagle DUB / 170mm / 32t
Cassette:SRAM XG1275 Eagle / 12-speed / 11-50t
Chain:SRAM GX Eagle / 12-speed
Bottom bracket:SRAM DUB / BSA-threaded / 73mm
Wheelset
Wheels:Sonder Nova 29"
Front tyre:Goodyear Newton MTF Trail Tubeless / 29 x 2.5" / black
Rear tyre:Goodyear Newton MTR Enduro Tubeless / 29 x 2.4" / black
Tubes:WTB Inner Tube / 29 x 1.9-2.3"
Finishing kit
Handlebars:Sonder Aspect Riser
Stem:Sonder Piskie
Seatpost:X-Fusion Manic dropper & lever / 31.6mm / 125mm (drop)
Saddle:Sonder Abode
Grips:Sonder Clutch
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
ZS44/28.6| ZS56/40 headset (frame and rear shock does not come with headset)
Reviews