Coilover Springs — Linear & Progressive Rate

Coilover Springs — Linear & Progressive Rate

Coilover springs are the replaceable compression springs that wrap around the shock body in a coilover assembly, determining ride height, spring rate, and the balance between comfort and handling stiffness. Swapping springs is the most direct way to tune a coilover setup for a new application without buying an entirely new system.

Popular Upgrades

Linear-rate springs in the 6 to 12 kg/mm range are the most popular choice for street performance and track day builds where predictable handling is more important than maximum compliance. Progressive-rate springs that soften on small bumps and stiffen under load are preferred for street cars that need to be both comfortable on rough roads and controlled in hard cornering. ID60 and ID65 springs are the most common inner diameter specifications across popular coilover platforms.

What is the difference between linear and progressive coilover springs?

A linear spring has a constant rate from full droop to full compression, providing consistent and predictable handling feedback throughout the suspension travel. A progressive spring uses variable coil spacing to deliver a softer initial rate that stiffens as compression increases, absorbing small impacts more comfortably while still providing resistance against bottoming in hard corners. Most track-focused builds use linear springs while street-focused builds often benefit from progressive rates.

How do I measure my coilover spring for a replacement?

Measure the spring inner diameter, free length when unloaded, and spring rate in kg/mm or lb/in. The inner diameter must match the coilover body OD, the free length should match the existing spring unless changing ride height, and the rate should be chosen based on vehicle weight and the handling balance you want to achieve. Most manufacturers label springs with ID, free length, and rate stamped directly on the coil.

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