A spindle knuckle assembly is a component used in vehicles' front suspension systems.
This assembly contains the spindle, which is the part of the suspension that connects the upper and lower control arms, and the knuckle,
which is the part of the suspension that connects the wheel hub and the spindle.
The assembly is responsible for allowing the wheel to move up and down as the vehicle drives over bumps and dips in the road surface.
It also provides the steering axis of the vehicle, which is the imaginary line that passes through the center of the spindle and perpendicularly to the road surface