Editing Caster angle (section)

{{short description|The angle between the vertical axis and  the steering axis of a steered wheel, in side view}}
[[image:caster angle.svg|thumb|250px|θ is the caster angle, the red line is the pivot line, and the grey area is the tire.]]
[[image:Suspension.jpg|thumb|250px|Front suspension of a race car{{px2}}{{mdash}}{{spcs|2|hair}}the caster angle is formed by the line between upper and lower ball joint]]
[[Image:Chopper WI.jpg|thumb|250px|An example of a [[Chopper (motorcycle)|chopper]] with a raked fork at an extreme caster angle]]
The '''caster angle'''<ref>{{cite web
|url = http://www.merriam-webster.com/dictionary/caster
|title = Merriam Webster Dictionary
|quote = caster ''n'' : the slight usually backward tilt from vertical of the axis of the steering mechanism of an automobile for giving directional stability to the front wheels
|access-date=2009-12-25}}</ref> or '''castor angle'''<ref>{{cite book
|title = Oxford English Dictionary
|url = https://archive.org/details/oxfordenglishdic0016unse
|url-access = registration
|edition = 2nd
|year = 1989  
|quote = castor angle, the angle at which the steering-head of the front wheels of a motor vehicle is set
|publisher = Oxford University Press}}</ref> is the angular displacement of the [[Bicycle_and_motorcycle_geometry#Steering_axis_angle|steering axis]] from the vertical axis of a steered [[wheel]] in a [[Automobile|car]], [[motorcycle]], [[bicycle]], other [[vehicle]] or a vessel, as seen from the side of the vehicle. The steering axis in a car with [[dual ball joint suspension]] is an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint, or through the center of the [[Kingpin (automotive part)|kingpin]] for vehicles having a kingpin. 

Caster causes a wheel to align with the direction of travel, and can be accomplished either by caster displacement or caster angle.  Caster displacement moves the steering axis ahead of the axis of wheel rotation, as with the front wheels of a shopping cart.  Caster angle moves the steering axis from vertical.<ref>{{citation |title=Learn Camber, Caster, and Toe |publisher=COME AND DRIVE IT  |url=https://www.comeanddriveit.com/suspension/camber-caster-toe |accessdate=January 5, 2021}}</ref>

In automobile racing, the caster angle may be adjusted to optimize handling characteristics for a particular venue. This is all connected to the front wheels.