One design challenge on a short-travel bike is to both absorb small bumps and control big impacts effectively. John Castellano has designed, patented and manufactured the Critically Damped Elastomer (CDE) Shock, which improves performance throughout the range of travel, compared to other types of shocks. Critical damping means “not too much, not too little”—just right.

The CDE shock is a compact, lightweight, reliable unit. It’s actually a two-stage shock providing isolation from small and large bumps alike. The first stage provides high-frequency isolation; for those smaller, but ultimately fatiguing bumps you encounter along the entire route of your ride. Interestingly, oil-damped airshocks are not as good at providing this high-frequency isolation on a short-travel bike, because the stiff spring and high damping rates required with this type of shock actually transmit, rather than absorb, high frequency harshness.

The CDE’s second stage is progressive, meaning the spring rate and damping increases as you increase the shock travel. The bigger the bump, the more the shock works to control the bump forces. This position-sensitive damping works on both compression and rebound to keep the tire pinned to the ground under all conditions.


Though sophisticated in function, the CDE is an exceedingly simple shock, with only 11 parts, and no pivots. All parts are user serviceable, and easy to replace. Grease ports are provided, to make it easy to maintain the shock. Each shock is custom tuned for rider size and weight. The shock is adjustable over a range of ±30 lb. in rider weight. In addition, you may order stiffer or softer springs for the shock to suit your own needs.