Serpent 500916 13mm Rear Spring RR 2.3lbs  [SER500916]

Rear Spring 13mm Diameter, Rate 2.3lbs

The Serpent 500916 is a 13mm outer-diameter coil spring in purple, specified at 2.3lbs, and supplied as a replacement for rear shock assemblies on general R/C cars. It lets racers and hobbyists change rear stiffness without disassembling the damper.

The spring primarily sets static ride height and contributes to linear spring rate through preload and installed length choices. When fitting, inspect spring seat geometry and retainers so the spring locates correctly and has full travel. Remember that optimal performance comes from matching spring rate with damper oil and piston settings for balanced rebound and compression control.

Setup suggestions: compress the shock to confirm smooth travel, alter preload in small increments while noting handling, and keep the spring finish clean to prevent seating issues in the retainer.