10mm shaft clamp required for fitment
For the first time, we created an air spring with a truly better spring rate, everywhere in the travel, than a coil. The Secus upgrade delivers the first and only air spring system to really come indistinguishably close to the linear spring rate of a coil fork for the entire first 2/3rds of its travel, with the advantage of a gentle end stroke progression to prevent bottoming without the “wall of force” harshness that excessively progressive springs create.
Secus Advantages:
- An enlarged negative air spring chamber delivers a soft, supple initial stroke for ultimate small bump compliance (yes, even compared to the Luftkappe)
- Proprietary Midstroke Support Valve improves predictability and support beyond the sag point
- Reduced lower leg pneumatic ramp means better scalability of the air spring, particularly for light riders who previously struggled to use full travel
- Plush and predictable like a coil, bottomless like an air spring
- Allows full use of travel in both directions - fully extends to topout without any quibbles (including on Debonair B1 air springs) and fully compresses without excessive ramp
- Allows more lower leg bath oil to be used for superior lubrication
- Considerably lighter than coil conversions - adds approximately 130g
- Simple setup - inflate fork, bounce on it a few times, press MSV charge button, go ride
- Compatible with OEM volume spacers for end-stroke progression adjustment
- Compatible with other aftermarket top-cap systems such as DSD Runt and MRP Ramp Control
- Lower compression ratios mean a more consistent spring rate
- Transferrable between any Secus-compatible forks with only a footstud to change at most
Three Stages of Control
By independently optimising the beginning, middle and end portions of the stroke, the Secus gives you the linear-to-progressive spring rate that coil springs and traditional air springs alike wish they had.

Initial stroke - enlarged negative air spring chamber delivers a soft, supple initial stroke for ultimate small bump compliance
Midstroke - where traditional air spring rates drop off in the midstroke, our proprietary Midstroke Support Valve technology boosts the midstroke spring rate to maintain linearity, for support, predictability, ride height and compliance
End stroke - enlarged lower leg volume reduces overall progression even at higher pressures and allows for a wider range of end-stroke ramp options to be utilised with standard fork volume spacers.
Fork | Year & Specification | Secus Variant |
Fox 32 | 2018+ (unless footnut on spring side is recessed) | Fox A1 |
Fox 34 | 2018+ (unless footnut on spring side is recessed) | Fox A1 |
Fox 36 | 2018+ | Fox A1 |
Fox 38 | 2020+ | Fox A2 |
Fox 40 | Coming soon | |
Fox 32 StepCast | Not Compatible | |
Fox 34 StepCast | Not Compatible | |
Marzocchi Z1 | 2019+ | Fox A1 |
Rockshox Pike / Revelation |
2019-20 compatible 2014-18 Pike requires 2019-20 (B1/B2) Debonair Airshaft update to be compatibleNote: C1 Debonair update (MY2021) not compatible - use B1/B2 sealhead or air shaft assembly. |
Rockshox A1 |
Rockshox Lyrik / Yari |
2019-20 compatible 2016-18 requires 2019-20 (B1/B2) Debonair Airshaft update to be compatible Note: C1 Debonair update (MY2021) not compatible - use B1/B2 sealhead or air shaft assembly. |
Rockshox A1 |
Rockshox Boxxer | 2019+ | Rockshox A2 |