Spring rates refer to the measure of how much force a spring can exert per unit of displacement. It is typically expressed in units like pounds per inch (lb/in) or newtons per millimeter (N/mm). A higher spring rate indicates a stiffer spring, which requires more force to compress or extend it, while a lower spring rate means the spring is softer and easier to compress. In applications such as automotive suspension systems, the spring rate plays a crucial role in determining ride comfort and handling. Engineers select specific spring rates to achieve desired performance characteristics, balancing factors like vehicle weight, road conditions, and driver preferences.