Compared to most existing systems out there SCAD provides a difference in the portion of travel from the fully extended position to the sag point. This is the portion of travel used when you sit on the bike, and what happens in this part of the travel is critical to bike performance when pedaling over bumps.
The response to pedaling forces above the sag point allows the suspension system to return to the sag point. (Traditionally other systems provide maximum anti squat when the suspension is fully extended which can unnecessarily hold up or extend the suspension.)
SCAD provides reduced anti squat (below 100%) when the suspension is extended above the sag point:
The benefits of these outcomes are explained here.
The goal with SCAD is to compliment the slightly lower anti squat above the sag point with a tuned higher anti squat (e.g. around 100% or slightly above) at and below the sag point. This provides for efficient pedaling and a firm feel under hard pedaling.
Test Proven Performance Benefits
Test results support the benefits of SCAD when pedaling over obstacles and up hills. Go here to see the results of the original Z-Link system.
SCAD was originally conceived around a simple concept. Reduce the anti squat above the sag point to focus the system dynamics towards the sag point.
The first generation of the Z-link system provided large reductions in anti-squat above the sag point. The second generation of the Z-link system refined this outcome - delivering a more stable anti-squat response across the travel range. See below
Now further evolution of the SCAD concept is underway.
New systems in development can be tuned to provide a very stable anti-squat response throughout the system's travel.
As shown below System X and System Y provide improved anti-squat stability.
Look out for further development of these systems.