This SAE Recommended Practice establishes performance guidelines for the threshold pressure and brake force output of the brakes on the axles of air braked towing trucks@ truck-tractors@ truck-trailers@ and converter dollies with GVWRs over 10000 lb designed to be used on the highway in combination with other air braked vehicles of this type in commercial operations. PURPOSE: The purpose of this recommended practice is to establish target threshold pressures and brake force outputs with reference to brake application pressures as measured at the rear control line gladhand of truck-tractors and towing trucks@ the control line gladhand of non-towing trailers@ and the front and rear control line gladhand of towing trailers and dollies.