The spacer ring in the brake adjusting mechanism of the Citroën 2CV is a crucial component ensuring the effectiveness of the braking system. This ring-shaped part acts as a spacer between the brake components, ensuring even wear and optimal braking power. It is designed to facilitate the proper interaction between the brake drum and shoe, extending the lifespan of the brake system. Though small in size, the spacer ring plays a critical role in the safety and performance of the 2CV, a classic car renowned for its simple yet innovative engineering.