Hot Racing Progressive Rate 1/16 Spring Set : 1/16 E-Revo VXL

This is the Multi rate Spring Set for the Traxxas 1/16 Shocks used on the Slash, Revo (1/16)

Spring Steel Construction
PROGRESSIVE Springs, PROGRESSIVE-Rate (PRS) allow the optimum spring rate for each application. These multi-rate springs are soft at the beginning to soak up the small bumps, but transitions (crosses over) to the stiff part of the rate to resist bottoming on jumps and other big "hits. "

Two 1.1mm wire Red PROGRESSIVE Rate Springs
Two 1.3mm wire Silver PROGRESSIVE Rate Springs
Two 1.5mm wire Gun Black PROGRESSIVE Rate Springs

Red
length: 25mm
Inner diameter: 11.2mm
Wire diameter:1.12
Silver
length: 22.5mm
Inner diameter: 11.2mm
Wire diameter:1.00
Black
length: 29mm
Inner diameter: 11.2mm
Wire diameter:1.00

Hot Racing progressive springs each coil is spaced differently and have a variable spring rate. When free, it is easy to compress progressive springs for first few mm. As you apply more forces, coil on a progressive spring come closer. After a certain point, coil at both end of progressive springs becomes inactive, and that makes the spring stiffer. Apply more forces to mid part of the progressive spring then it becomes stiffer because as the number of active coils in a spring decreases, the spring rate increases. So, progressive springs may both be sensitive to very small bumps on the road, while giving the stiffness you need during hard braking and turning.