F 150 4WD V8-4.6L (2008)
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.
Nibble
Sometimes confused with shimmy, nibble is a condition resulting from tire interaction with various road surfaces and observed by the driver as small
rotational oscillations of the steering wheel. For wheel and tire diagnosis, refer to Section 204-04.
Poor Returnability/Sticky Steering
Poor returnability and sticky steering is used to described the poor return of the steering wheel to center after a turn or the steering correction is
completed.
Drift/Pull
Pull is a tugging sensation, felt by the hands on the steering wheel, that must be overcome to keep the vehicle going straight.
Drift describes what a vehicle with this condition does with hands off the steering wheel.
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A vehicle-related drift/pull, on a flat road, will cause a consistent deviation from the straight-ahead path and require constant steering input in the
opposite direction to counteract the effect.
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Drift/pull may be induced by conditions external to the vehicle (for example: wind, road crown).
Poor Groove Feel
Poor groove feel is characterized by little or no buildup of turning effort felt in the steering wheel as the wheel is rocked slowly left and right within
very small turns around center or straight-ahead (under 20 degrees of steering wheel turn). Efforts may be said to be "flat on center."
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Under 20 degrees of turn, most of the turning effort that builds up comes from the mesh of gear teeth in the steering gear. In this range, the steering
wheel is not yet turned enough to feel the effort from the self-aligning forces at the road wheel or tire patch.
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In the diagnosis of a roadability problem, it is important to understand the difference between wander and poor groove feel.