Q: What is a dual-rate spring and why does it matter here?

Each spring has two rates in one unit. The initial rate is about 25 percent softer than factory for a supple feel over everyday bumps and potholes, then a firmer secondary rate engages under cornering, braking, or higher speeds to resist body roll and keep the chassis flat. For a first-gen Model Y with settled original springs, that restores a controlled ride height while improving on the car’s new-from-factory ride.