A condition generally produced in the front wheels when they are attached to the ends of a beam axle . It is particularly noticeable on rough roads and the shimmy at the steering wheel makes it difficult to control the vehicle. You have probably seen this condition in a shopping cart that has caster wheels that wiggle or fluctuate back and forth and will not roll in a straight line.
CASTER WOBBLE
Meaning of CASTER WOBBLE in English
English dictionary of automotive terms. Английский словарь автомобильных терминов. 2012