At what pressure should the air compressor cut in?

The air compressor in a tractor-trailer system is designed to maintain adequate air pressure in the air tanks to ensure that braking systems and other pneumatic components function correctly. The cut-in pressure is the threshold at which the compressor begins to operate and refill the tanks after the pressure drops below a certain level.

A cut-in pressure of 85 psi is generally within the standard range for most commercial vehicles. This threshold ensures that the necessary air supply is maintained for braking and other systems, preventing any loss of performance or safety issues. Each vehicle manufacturer may have specific recommendations, but 85 psi is commonly accepted as a balanced level that allows for proper operation of the air brake system while also avoiding excessive wear on the compressor.

The other options may be too low for efficient operation, potentially leading to insufficient air pressure for braking needs, which introduces a risk of brake failure or reduced braking efficacy. Achieving a higher cut-in pressure can be beneficial, but excessively high thresholds can lead to increased wear on the compressor and the risk of system failure. Thus, the selection of 85 psi as the cut-in pressure aligns with operational safety and maintenance standards for commercial driving.