Condition:
This Cortex is a lightly used ex-display bike with a scratch on the forks and a chip on the DS seatstay. See the photos.
Fast and agile, Cortex is for epic days over mixed terrain. 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.
At a Glance
Fast and agile short travel full sus 29er; perfect for mixed terrain and day long epics
Frame: Sonder Cortex 120 mm travel, hand-welded 6061 double butted aluminium
Fork: Rockshox Revelation RC / 29 / 130mm
Rear Shock: Rockshox Deluxe Select+ / 190x45
Groupset: SRAM NX Eagle, 1x12, 11-50
Brakes: SRAM Guide T
Seat Post: Love Mud Membar
Wheelset: Love Mud Hobo 29er
Up to date geometry for trail bike agility and enduro bike stability
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.
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 top tube to your crotch this will give you enough seat post 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 +

Size | Small | Medium | Large | X-Large |
---|---|---|---|---|
ST - Seat tube | 395 | 445 | 470 | 508 |
ETT - Effective Top tube | 592 | 616 | 644 | 668 |
TT - Top tube | 600 | 615 | 628 | 646 |
HT - Head tube | 120 | 135 | 145 | 160 |
HA - Head angle | 68 | 68 | 68 | 68 |
SA - Seat angle | 73 | 73 | 73 | 73 |
CS - Chainstay | 440 - 460 (adjustable) | 440 - 460 (adjustable) | 440 - 460 (adjustable) | 440 - 460 (adjustable) |
BB - BB drop | 58 | 58 | 58 | 58 |
FO - Fork offset | 50 | 50 | 50 | 50 |
WB - Wheelbase | 1142 | 1154 | 1168 | 1190 |
SO - Stand over | 736 | 767 | 782 | 808 |
RE - Reach | 410 | 430 | 455 | 475 |
SK - Stack | 595 | 609 | 618 | 632 |
Build | Cortex NX Eagle Recon |
---|---|
Frameset | |
Frame: | Sonder Cortex Frame |
Fork: | Rockshox Revelation RC / 29 / 130mm |
Rear Shock: | Rockshox Deluxe Select+ / 190x45 |
Headset: | Love Mud Rumour / ZS44/ZS56 |
Seat Clamp: | Love Mud Gromit / 34.9mm |
Group Set | |
Brake Front: | SRAM Guide T / 950mm |
Brake Rear: | SRAM Guide T / 1800mm |
Rotor Front: | Avid Centreline Rotor / 180mm |
Rotor Rear: | Avid Centreline Rotor / 160mm |
Rear Mech: | SRAM NX Eagle Rear Derailleur / 12 / Long |
Rear Shifter: | SRAM NX Eagle Trigger Shifter |
Chainset: | SRAM NX Eagle Crankset DUB / 170mm / 32 |
Bottom Bracket: | SRAM Bottom Bracket / DUB |
Chain: | SRAM NX Eagle Chain / 118 Links |
Finishing Kit | |
Stem: | Love Mud Piskie Stem / 31.8mm / 45mm |
Seatpost: | Love Mud Membar |
Saddle: | Love Mud Abode / Black |
Tape/Grips: | Love Mud Clutch / Black |
Handlebar: | Love Mud Aspect Riser |
Wheelset | |
Wheels: | Love Mud Hobo 29er |
Front Tyre: | WTB Vigilante / Light High Grip / 29 / 2.5 |
Rear Tyre: | WTB Trail Boss / Tough Fast Rolling / 29 / 2.4 |
Tubes: | WTB Inner Tube / 29 / 1.9-2.3 |
Weight | |
Frame: | S: TBC; M: TBC; L: TBC; XL: TBC |
Built: | S: TBC; M: TBC; L: TBC; XL: TBC |
Pedals not included with full builds |
Weight (kg): S: 2.73; M: 2.91; L: 3.05; XL: 3.11 |
Hydroformed and custom butted alloy frame tubing |
Internal cable routing |
Rear Shock: Rockshox Deluxe Select+ 190 x 45 mm |
Horst link suspension layout |
120 mm rear travel; 130 mm fork travel |
Clearance for up to 29” x 2.6 in wide tyres |
73 mm BSA threaded bracket shell |
148 x 12 mm 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) |
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.

The Details
Ex-Display Cortex NX Eagle - Large in action
