Spring rate and wheel-frequency calculator that tells you what springs to fit, why, and which part to order.
- Calculates wheel rate, natural frequency, critical damping and static deflection from corner weights, unsprung mass and motion ratio — both axles at once.
- Soft / Recommended / Hard spring suggestions tuned to your car's use and drivetrain layout.
- Built-in spring catalogue lookup and motion-ratio guide, fully offline — no account, no subscription.