Launched as a playful and affordable aluminium 29er a few seasons ago, the Sonder Cortex featured 120mm of rear-suspension travel and a 66-degree head angle. Sonder’s product designers have now added 10mm of travel in the rear and changed the Cortex’s geometry, creating a more complete trail bike for greater descending confidence.
The most significant changes are those new suspension bits, with 135mm of rear travel at its disposal and a 140mm fork. But it’s not only about adding more suspension travel and hoping for the best. The Cortex also features variable chainstay lengths according to frame size, which should aid weight distribution when standing on the pedals during a descent – or leaning aggressively into hairpin corners.
Balancing the increase in suspension travel, the variable chainstay lengths, and slacker geometry. Sonder’s designers have also slackened the head angle to 65 degrees, but reach numbers remain unchanged across the four frame sizes. The Cortex small has 420mm of reach, the medium 440mm, the large 465mm and an extra-large measures 485mm of reach.
For all the benefits of more suspension travel, more aggressive geometry and variable chainstay length, tyre clearance has narrowed with the new Cortex. The 120mm Cortex had adequate rear triangle clearance for 29 x 2.6in tyres, but with the new bike, that slims down to 2.4in.
Component details are all about durability and lowering the burden of DIY maintenance. SRAM’s UDH is standard, making repairability of those rear-mech rock strikes less of a nightmare and a threaded 73mm bottom bracket should help prevent the dreaded fine-dust creak in summer.
The Cortex is about bringing value to riders who want a dual-suspension trail bike and aren’t frame material snobs. That’s why Sonder has curated a range of nine derivatives, with prices starting at only £2,149 for a Shimano Deore build. Upgrading to SLX is £2,349, while an XT build prices at £2,999.
If you prefer SRAM build kits to complete your new Cortex, the SX Eagle is £2,049, with an NX build costing £2,349 and GX at £2,999. A Cortex GX Eagle build is £3,399, with the XO option at £4,199. If you like the components you have, the new Cortex frameset is £1,599.
