Steering System Symptom Definitions: Shimmy
WARNING: This page is about a different car, the 2002 Ford RV Cutaway, 2002 Ford Econoline, 2002 Ford E550 Super Duty, 2002 Ford E450 Super Duty, and 2002 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
Shimmy, as observed by the driver, is large, consistent, rotational oscillations of the steering wheel resulting from large, side-to-side (lateral) tire/wheel movements.
Shimmy is usually experienced near 64 km/h (40 mph), and can begin or be amplified when the tire contacts pot holes or irregularities in the road surface.