Isn't the bar on the bottom there to prevent wind up? Spring is just to hold the car up,
Exactly, and the front leaf acts like the top link in a 4-link or the top bar in a ladder bar.
Not to say the CalTrac wouldn't work with a S/S spring but the spring front segment is designed to have very little wrap-up. With the CalTrac system, its the wrap-up of the front segment that slaps the bar up and plants the tire. With the S/S springs you'd have to adjust the bar to have very little movement because there's no wrap-up and subsequently no "shock" - therefore virtually none of the affect they're designed for.
