Flex
One movement releases the midsole, so the shoe rolls and adapts with the terrain — the behaviour you want on uneven ground and long distances.
European patent · working prototype
One shoe. Every sole you need.
FX-i invented the patented flex-fix mechanism: with a single movement the wearer flexes or fixes the sole of the shoe they are already wearing. We are here to improve the way you move.
The sole should follow the activity
What a sole needs to do is determined by the activity, its duration and the surface underfoot. That is why footwear is sold one purpose at a time: a shoe for the trail, a shoe for the road, a boot for the job.
FX-i makes it possible to combine the properties of different sole types in a single shoe — and to let the wearer choose between them, step by step, activity by activity.
That combination also makes the differences visible. Wearers learn which sole behaviour suits them best in which conditions, and can customise the shoe from there. We believe combining sole properties should become the standard brief for every footwear designer.
The flex-fix mechanism
Two soles in one, switched by the wearer
The mechanism is built into the midsole. A single movement flexibilises or fixes it — no tools, no power, no app.
Fix
The same movement fixes and stabilises the sole, giving the support and torsional stiffness a heavier activity or a heavier load demands.
Fail-safe by design
The wearer sets the sole; the shoe never overrules the wearer. If the mechanism fails, the sole simply returns to its default setting and behaves like a conventional sole.
Where it applies
Anywhere versatility matters and terrain changes: from multi-day hikes to demanding professional use. The potential beyond footwear’s obvious categories is what makes flex-fix a platform rather than a feature.
- Hiking & trekking
- Trail running & cross-country
- Endurance sports
- Multi-purpose everyday footwear
- Professional & duty boots
- Extreme environments
From proof of concept to the best shoe in the world
Development follows the Technology Readiness Level model, with objective, traceable checks at every stage — so partners can see exactly what has been proven and what comes next.
TRL 3Achieved
Proof of concept
A working flex-fix mechanism built into the midsole of a hiking shoe — a functioning prototype, not a drawing.
TRL 4-5Next
Robustness & reliability
Translating the strength and durability of an A-brand quality sole into objective criteria, then matching them in the lab with the mechanism built in.
TRL 6-8Planned
Comfort & performance
Establishing which sole properties actually improve wear comfort and performance, engineering them in, and validating them in demonstration.
FX-i holds a European patent for the application of the flex-fix mechanism in a shoe sole and has demonstrated a working prototype: a hiking shoe with the mechanism built into the sole.
For investors
A granted European patent, a proven mechanism and a clearly staged development plan towards lab-validated robustness and reliability. We are raising to fund the engineering and testing programme.
For launching customers
Brands and organisations that want a genuinely versatile shoe can shape the requirements with us and be first to bring flex-fix soles to their users.
Let’s move this forward
Investing, co-developing or piloting — we’re glad to walk you through the patent, the prototype and the development plan.
info@fx-i.eu