The Bendix® LQ-5™ ratio valve can be used in a variety of applications, including truck-tractors, straight trucks, school buses and transit buses. For truck-tractors, it is used on the front (steering) axle of tractor air brake systems to proportion brake application pressure during normal tractor-trailer operation. Alternatively, the LQ-5 ratio valve can be used on the rear axle (or rear axle group) of long wheelbase vehicles to reduce brake application pressures during moderate control pressure actuations. In this configuration, it is designed only for long wheelbase vehicles, and is not to be used in other vehicle applications.