What is a primary characteristic of hydraulic fluids that affects performance?

The primary characteristic of hydraulic fluids that significantly impacts performance is lubricity. Lubricity refers to the fluid's ability to reduce friction between moving parts within a hydraulic system. This property is crucial because adequate lubrication helps prevent wear and tear on components, ensuring smooth operation and extending the lifespan of the system. Good lubricity also aids in heat dissipation and can help prevent overheating by maintaining a consistent operational temperature.

While aspects such as viscosity, conductivity, and density are important in evaluating the overall performance of hydraulic fluids, they relate more to how fluids flow, transfer heat, and how much pressure they can withstand rather than their effectiveness in reducing wear. Thus, lubricity stands out as a defining property that directly contributes to the maintenance of efficient operation in hydraulic systems, ensuring reliable performance in various conditions.