YOKOMO R12/GT series Shock Spring Cup R12-37C - Yokomo  [R12-37C]

Shock spring cup summary

This RC shock spring cup is made for Yokomo R12/GT series touring car shocks and secures the spring on the shock shaft to give a defined contact point for preload and travel adjustment. It is intended to lock spring position and improve consistency during normal rebuild and tuning work.

Installation is simple: remove the shock cap and any threaded collars as needed, place the cup onto the shock shaft seating surface, then reassemble while ensuring the spring seats squarely. Use small hobby hand tools and confirm there is no unwanted play after tightening. No special press is required for fitting on compatible shock bodies.

Tuning notes: moving the cup changes effective spring preload and the initial travel stop, which in turn affects ride height and transient response. Make small adjustments and test on-track to understand handling changes. Regularly inspect the cup for burrs or deformation to maintain reliable spring seating.