Article: Calyx™ - What You Should Know
Calyx™ - What You Should Know
Originally developed as a modern interpretation of the camp shoe, the Calyx™ is Purple Mountain Observatory's debut footwear silhouette, developed in collaboration with Vibram.
Designed for the moments after outdoor activity, the shoe combines an unconventional approach to upper construction with Vibram's specialist outsole technology. Its seamless waterproof Strat-X shell, and MegaGrip Grivola sole put function at the centre of the design.
Now returning for a second iteration, we look more closely at how Calyx™ is constructed, the technology beneath it and where those technologies make a difference.
What Is a Camp Shoe?
Traditionally, a camp shoe serves a different purpose from the footwear worn throughout a hike. After prolonged activity, walking boots or trail shoes are removed in favour of something easier to wear around the campsite.Something which keeps your feet dry, and more importantly...comfortable.
What Is Vibram Strat-X™?
One of the defining characteristics of Calyx™ is the way its outer shell is made. Vibram Strat-X uses an advanced thermoforming process to shape a specialised rubber sheet into a three-dimensional upper.
Conventional uppers frequently bring together separately cut panels, stitching, overlays and bonding. Strat-X instead allows the external rubber shell to be formed as one single structure. It is this process that gives Calyx™ its recognisable shape.
Calyx™ / Upper construction
Calyx™ / Vibram material detail
How Does It Work?
Many technical shoes achieve waterproofing through a membrane beneath a fabric or synthetic upper. Calyx™ uses a different approach: its Strat-X rubber shell is itself waterproof, providing the primary material barrier against external moisture. That construction makes sense for damp grass, rain and unexpected puddles which you're bound to step in.
Vibram Grivola & Megagrip
While Strat-X defines the upper, the Vibram Grivola outsole supports the shoe underfoot. It incorporates Vibram Megagrip, a rubber compound developed to provide traction on wet and dry surfaces while balancing grip and durability.
Outsole performance depends on more than rubber alone. Tread geometry, terrain and the condition of the surface all influence traction. By pairing a defined Grivola tread with Megagrip rubber, Calyx™ extends the practical possibilities of the traditional camp shoe.
Vibram Grivola outsole / Megagrip compound
What's Changed for the Second Iteration?
The returning Calyx™ retains the defining Strat-X upper and Vibram Grivola outsole. Updated sole treatments, including gum-coloured and dual-colour speckled finishes on selected colourways, reconsider the relationship between the sculpted upper and the outsole without changing the overall direction of the design.
Calyx™ / Sculpted toe-box detail
Calyx™ / Outsole and sidewall
PMO's Approach
Originally designed for life after a hike, Calyx™ has found its place well beyond the campsite. Built around Vibram's Strat-X technology and Megagrip outsole, it brings together an unconventional construction process with the functionality needed for everyday use.
PMO / VIBRAM CALYX™
Explore Calyx™
Discover the second iteration in Black, Stone and Grey. Select a colourway and explore available sizes on the product page.
