• Cortex Frameset
  • Cortex Frameset
  • Cortex Frameset
    • Preorder

    Cortex Frameset

    Mid travel 29er frameset

    £1,449 £1,599

    or from £25 /month V12 logo


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    Buy Now. Be Riding Next Week.

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    • Customise and buy now. Deliveries from 22nd July




    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.


    Rockshox Deluxe Select+ / 210 / 50
    Rockshox Deluxe Select+ / 210 / 50


    Rockshox Deluxe Ultimate / 210 / 50
    Rockshox Deluxe Ultimate / 210 / 50 Black


    Cane Creek DBair IL / 210 / 50
    Cane Creek DBair IL / 210 / 50 Black



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      No Headset
      No Headset


      FSA [OEM] Orbit N0.57E Headset / 8.2mm Spacer
      FSA Orbit N0.57E Headset / 8.2mm Spacer Black


        Initial Price

        Cortex Frameset / Select a frame...



        Total Price

        V12 Interest Free Finance
        Buy Now. Be Riding Next Week.

        Fast and agile, Cortex is a mid-travel full suspension trail bike frameset for big mountain epics on all terrain and flying round your local trail centre. It comes alive on long technical descents with 135mm travel at the rear (we recommend a 140mm travel fork) big wheels and a stiff, responsive frame.

        With bang up to date geometry, Cortex inspires confidence 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 your grin.

        The tried and tested Horst link design keeps the suspension active when braking. We've fine tuned the leverage curve and worked with SRAM RockShox to produce a rear shock that's custom-tuned for the Cortex - maximum downhill performance while maintaining the all-day pedalling efficiency from its predecessor. Cortex is your do-it-all bike of choice for lakeland 30-milers and flat-out trail centre laps alike; with enough travel to carry speed over longer sections of rough ground and a lively, playful feel through the twisty bits.

        Cortex' frameset is hand-welded from 6061 double-butted aluminium for the perfect mix of weight, rigidity and durability; with a slim hydroformed top-tube and down-tube designed to improve stiffness with just enough compliance to get you out of trouble. Internal cable and stealth dropper routing means clean lines, dampened with foam liners for a quiet ride. Dialed-in geometry and 2.4” tyre clearance gives heaps of grip; a comfortable and efficient climbing position for big days in the saddle; and a stable, spirited platform for smashing down descents.


        Up to date trail bike geometry

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

        Increased chainstay length for the Large and XL frames maintains consistent weight distribution for riders of all heights.

        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. We've worked with SRAM to produce a rear shock that's specifically tuned for the Cortex - and made sure those benefits are felt across a wider range of rider size and weight.

        140mm travel at the front and 135mm at the rear lets you carry higher speeds over rough ground without sacrificing pedalling efficiency.

        Horst link suspension design

        The tried and tested Horst Link suspension design allows the suspension to stay active when braking. We've fine-tuned the suspension leverage curve to maximise performance on the downhill while maintaining efficient uphill pedalling - so no need for climb switches.

        Internal cable routing

        Internal routing in the front triangle makes for clean lines and tidy cables, with dampened foam liners for a quiet ride.

        Universal Derailleur Hanger UDH

        Keeping up with industry standards, Cortex uses a UDH hanger. They're widely available so you can get rolling again sooner after any mid-ride mishaps!

        The UDH also makes Cortex compatible with the latest SRAM Transmission groupsets.

        Geometry and Sizing


        Rider Height

        5ft 2in - 5ft 7in 


        5ft 6in - 5ft 10in


        5ft 9in - 6ft 2in


        6ft 2in + 

        (187cm +)

        ST - Seat tube400410440460
        ETT - Estimated top tube576597625647
        HT - Head tube100105115125
        HA - Head angle65656565
        AC - Axle to crown550550550550
        SA - Seat angle75.675.675.675.6
        CS - Chainstay440440445445
        BB - BB drop40404040
        FO - Fork offset44444444
        WB - Wheelbase1173119512291253
        RE - Reach420440465485
        SK - Stack608614624633
        Frame Spec
        Weight: S: TBCkg; M: TBCkg; L: TBCkg; XL: TBCkg (plus shock 0.4kg)
        Hydroformed and custom butted alloy frame tubing
        Internal cable routing
        Rear Shock: 210x50mm metric shock – Custom tuned for the frame
        Horst link suspension layout
        135mm rear travel; 140mm fork travel
        Frame clearance for up to 29 x 2.4" wide tyres
        BSA BB with ISCG-05 chain guide tabs
        UDH Boost 148 x 12mm rear thru-axle
        31.6mm seat tube, 34.9mm clamp
        Headset: ZS44/28.6 top, ZS56/40 bottom

        • Cortex Frameset
        • Cortex Frameset
        • Cortex Frameset