SPRINGRATES

Most coilover buyers obsess over brand and damping levels and completely overlook spring rate. That's the number that actually determines how your car compresses, recovers, and grips through every input you give it.

Spring rate is measured in kg/mm or lb/in and it controls ride comfort, body control, mechanical grip, and damping balance. The wrong rate doesn't just feel bad — it actively undermines everything else you spent money on.

The good news: brands like BC Racing, Riaction, Silvers, and Fortune Auto ship their kits with carefully validated defaults. For the majority of builds, those defaults are the correct starting point. Swapping rates without understanding motion ratio, damper valving, and chassis weight distribution is how you make a good kit worse.