Suspension testing equipment has previously been designed to provide the time-domain response of the automotive suspension. The results of this type of test, although quantitative, are dependent on all suspension components, and are unreliable in determining the safety of the vehicle and condition of the dampers. Frequency domain suspension testers have also been designed; however, they have been limited to the magnitude response of the suspension system. This result, usually referred to as “road” adhesion, is indicative of the safety of the vehicle; however, it is unreliable in determining the performance of the dampers. The present apparatus provides, along with the magnitude response (adhesion), the phase response of the wheel versus the road surface irregularities. This information, including a quantity known as “minimum phase angle,” gives valuable information as to the suspension damping value.