Abstract: The brakes of a two-axle vehicle are tested by weighing the vehicle and measuring the braking forces for both axles to determine the actual ratio of front axle braking force to total braking force. The deceleration applied to the vehicle is determined from the weight of the vehicle and the applied braking forces. A nominal preferred value of the ratio of front axle braking force to total braking force is calculated from the determined deceleration and the measured weight of the vehicle. The nominal preferred value varies from test to test with both the actual deceleration and the vehicle weight. For each test, upper and lower limits for the acceptability of the actual ratio of front axle braking force to total braking force are set based upon the computed nominal preferred value. These limits move from test to test with the computed nominal preferred value. The nominal preferred value, the movable limits, and the actual ratio are displayed to the user on a CRT screen.

Abstract: A sideslip meter includes first and second parallel runways. The first runway has a measurement plate movable laterally with respect to the direction of travel of the vehicle along the runway as a tire of said vehicle passes over the measurement plate. A lateral movement sensor senses the amount of lateral movement of the measurement plate and provides a corresponding output signal. First and second switches are spaced along the first runway. Each switch is actuated by the passage of a vehicle tire so that passage of the vehicle causes first one and then the other of the switches to be actuated. A display is provided for displaying information concerning lateral movement of the measurement plate. A control circuit determines vehicle velocity and vehicle direction from the actuations of the first and second switches and inhibits the display if the velocity is too fast or too slow, or if the vehicle is going backwards over the runways.

Abstract: The brakes of a two-axle vehicle are tested by weighing the vehicle and measuring the braking forces for both axles to determine the actual ratio of front axle braking force to total braking force. The deceleration applied to the vehicle is determined from the weight of the vehicle and the applied braking forces. A nominal preferred value of the ratio of front axle braking force to total braking force is calculated from the determined deceleration and the measured weight of the vehicle. The nominal preferred value varies from test to test with both the actual deceleration and the vehicle weight. For each test, upper and lower limits for the acceptability of the actual ratio of front axle braking force to total braking force are set based upon the computed nominal preferred value. These limits move from test to test with the computed nonimal preferred value. The nominal preferred value, the movable limits, and the actual ratio are displayed to the user on a CRT screen.

Abstract: A wobble run-out compensation system includes a compensation plate mountable with respect to a vehicle wheel. First and second manually operable adjusting members allow for independently adjusting the orientation of the compensation plate in first and second orthogonal planes, an adjustment in one plane not affecting the orientation of the plate in the other plane. The orientation of the compensation plate in each of the first and second planes is electronically sensed and substantially continuously displayed on an electronic display as that orientation is being adjusted so that the user is able to observe changes on the electronic display in the orientation of the compensation plate as manual adjustments are made.

Abstract: A measuring apparatus for measuring a vehicle wheel alignment characteristic, such as camber, includes a transducer mountable with respect to a vehicle wheel. The transducer has a movable arm repetitively driven along its path of travel to and away from a first predetermined position. Its presence is sensed only at the first predetermined position, the alignment characteristic of the wheel being a function of the time the arm is present there. The transducer generates a digital signal having a duty cycle characteristic of the value of the alignment characteristic being measured. The amount of time the digital signal is in a first state is digitally recorded, as is the amount of time the digital signal is in the opposite state. The value of the alignment characteristic is digitally determined as a function of the two digitally recorded times.