A tender spring looks like a mistake. Bolt a soft, almost floppy coil on top of a stiff main spring and it seems like you’ve ruined a perfectly good suspension. You haven’t. You’ve built a dual-rate system out of two linear ones. The trick is series stacking. Put two springs end to end and they carry the same force while their deflections add. That inverts the intuition: - Springs in parallel add stiffness - Springs in series add compliance - Combined rate: k = (k1 x k2) / (k1 + k2) The combined rate is always softer than the softer spring alone. While both coils are live, a 200 lb/in main paired with a 100 lb/in tender behaves like roughly 67 lb/in: plush over small bumps, expansion joints, broken pavement. Then the tender spring runs out of travel. It reaches coil bind, every coil touching, no more deflection, effectively a solid spacer welded into the stack. From that crossover point on, only the main spring works. The rate snaps back to the full 200 lb/in for body control, corn...