A Bumpstop is a progressive secondary spring at the end of suspension compression travel that prevents the suspension from contacting metal-on-metal bottoming. Modern bumpstops are tuneable secondary spring elements, not just travel limiters — they engage progressively to add wheel rate at full compression, supporting aerodynamic loads and managing extreme weight transfer. Proper bumpstop tuning is critical in low ride-height performance applications where the suspension lives close to bumpstop engagement.