Diaz Suspension Design

Runt Cartridge Fox 40 200mm

Diaz Suspension Design Runt Cartridge Fox 40 200mm turns your fork into a precision-tuned performance machine. This upgrade delivers the buttery smooth feel of a coil spring with the adjustability and light weight of air. Riders chasing better support, control, and traction on aggressive terrain will find the Runt an instant improvement to their Fox 40 setup.

With its dual-chamber, patent-pending design, the Runt creates a near-linear compression curve that mimics coil-like sensitivity while keeping the responsiveness and fine-tuning options of an air spring. The secondary air chamber adds tunable progression, giving you control over bottom-out resistance without the need for tokens or spacers.

Installation is straightforward—just drop it in and ride. The result is a fork that tracks better through chatter, resists diving under braking, and offers a more predictable mid-stroke feel. Whether racing downhill or charging bike park laps, the Runt keeps your suspension composed and confidence high.

Key Features:

• Dual-chamber air spring design for a coil-like feel with full air adjustability
• Built-in tunable progression via secondary air chamber and valve
• Easy drop-in installation—no special tools or permanent mods required
• Approximately 1/2 lb lighter than coil conversions
• Only 20g heavier than equivalent tokens or spacers
• Maintains full compatibility with existing air spring systems
• Fits 2018+ Fox 40 forks with 200mm travel

The Diaz Suspension Design Runt Cartridge gives riders the best of both worlds—coil-like traction and comfort, with the tunability and efficiency of air. It’s a smart, high-performance upgrade for serious riders who want their suspension dialed perfectly for every descent.