What are Digressive Rate Pistons?

What are Digressive Rate Pistons?

Toyota AE86 Corolla at Nurburgring

Stiff Damper Characteristics

  • A stiffer damper will ride stiffer over bumps and provide more body control and vice versa with a softer damper setting. A shock tuned to have a linear rate is often set up with at least some compromise in mind.
  • The stiffer your damper is set up to better manage body motions, the firmer your ride quality will be.
  • Too stiff and the car will become unsettled over bumps, too soft and the car will be floaty. This makes it difficult to have a coilover or damper system that can perform well on track or when driven hard and still ride comfortable for a daily driver.
Shock Info Graph Linear vs Digressive vs Progressive Rates

Coilovers featuring Digressive damper rates are one the new hot ticket items to hit the aftermarket suspension industry, but are they worth the hype? To understand the massive benefits of a digressive rate piston we first have to understand what high speed and low speed compression each control in regards to your ride and handling.

High Speed Compression vs. Low Speed Compression

  • High speed compression is the firmness of your damper in high speed events. This is responsible for how your car reacts over bumps or rough surfaces.
  • Low speed compression, as you might imagine, is the firmness of your damper over low speed events, meaning how firm the damper is at managing body motions attributed to driver input. Think squatting under throttle input, diving under braking, and body roll around turns.
Ford Mustang Drifting

The Benefits of a Digressive Rate Piston

The magic of the digressive rate piston is that it can retain softer and compliant high speed compression characteristics while having relatively stiff low speed compression characteristics.

Pros - Firm low-speed compression means less body roll, nose dive, better daily driven handling.

Cons - not as 'soft' or 'plush' as a linear piston counterpart (Fox, Rancho)

This makes the shock incredibly active and compliant over bumps and rough roads while being firm and resistant towards unwanted body motions making the car that much more stable. Essentially you can have a setup that will do a better job of managing unwanted body motions while also still providing a compliant ride, so that you can achieve the maximum performance of your vehicle possible while making less compromises.