Elastokinematics and Compliance Steer
Elastokinematics describes suspension movement caused by elastic deformation under force, while compliance steer is the resulting change in wheel steer or toe.
Where the movement comes from
Rubber bushings, ball joints, wheel bearings, links, subframes, mounts, and the body all deflect to some degree. Tire, braking, drive, cornering, and road forces can therefore change wheel position and alignment even if the rigid-link kinematic geometry is unchanged.
Intended tuning and unwanted change
Engineers can use controlled compliance to filter harshness, reduce disturbance at the steering wheel, or create stabilizing toe changes. The response depends on force direction and magnitude, bushing axes and stiffness, load path, temperature, frequency, and the complete suspension geometry.
Wear, torn bushings, loose joints, deformation, or incorrect installation can produce a different response from the intended design. Static wheel alignment may still appear acceptable while loaded toe or camber behavior is not.
Related but separate terms
Bump steer is the kinematic steer change caused by suspension travel. Compliance steer is caused by force-driven deformation. In a real maneuver both can occur together, so a test must state whether it prescribes wheel displacement, applied force, or both.
For rigid-body wheel paths and compliant force responses, see Suspension Kinematics and Vehicle Dynamics.