In automobiles, a wheel spindle is the part of a suspension system that carries the hub for the wheel and attaches to the upper and lower control arms.
Spindles are carried by steering knuckles or "uprights". Although the terms "steering knuckle" and "upright" are sometimes used interchangeably with "spindle", they all refer to different parts.
See also Front axle assembly List of auto parts Pintle Stub axle
References
List of Spindles/Uprights available in Australia suitable for Race, Modified and Individuality Constructed Vehicles