11. The next measurement is from the centerline of the control arm bushing to the point on the control arm directly under the center of the spring or the coilover assembly, then measure the angle of the centerline of the coilover from the horizontal of the control arm (or axle if calculating the rear). Armed with that information. go to the RideTech website and find the shock with dimensions suitable for your application. Then plug all the measurements into the spring calculator. You’ll be able to choose springs for a cruising/daily driving, performance driving, or racing.