Performance Online offers variable rate rear coil springs for you 1960-72 Chevy C10 truck.

The spring rate changes with the travel of the spring as opposed to having a constant rate as in a conventional standard or heavy duty spring. This is accomplished through a progressive spacing of spring coils. The tightly wound coils provide conventional ride characteristics while the wide spaced coils provide the additional load carrying capacity. Variable rate coils are ideal for applications where heavy loads are carried most of the time. They are great for towing and light truck use.

Load deflection example

Conventional spring: Variable rate spring:

200lbs = 1.00″ deflection 240lbs = 1.00″ deflection

400lbs = 2.00″ deflection 600lbs = 2.00″ deflection

600lbs = 3.00″ deflection 1100lbs = 3.00″ deflection

Static spring rate of these rear coils starts at 950lbs