Caster angle - Revision history

PNiddy: /* See also */

2006-07-19T14:23:43Z

PNiddy: /* See also */

2006-07-19T14:23:20Z

See also

← Older revision		Revision as of 14:23, 19 July 2006
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	== See also ==		== See also ==
	*[http://www.ozebiz.com.au/racetech/theory/align.html Camber, Caster, Toe - What does it all mean?]		*[http://www.ozebiz.com.au/racetech/theory/align.html Camber, Caster, Toe - What does it all mean?]
	* [[Camber angle]]		*[[Steering]]
			**[[Rack and pinion]]
			**[[Ackerman steering geometry]]
			**[[caster angle]]
			**[[Camber angle]]
	* [[Toe (automotive)]]		* [[Toe (automotive)]]
	* The 1896 [[Arthur Krebs]] automobile English patent: [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-01.jpg page 1] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-02.jpg 2] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-03.jpg 3] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-04.jpg 4] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-05.jpg 5] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-06.jpg 6] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-07.jpg 7] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-08.jpg 8] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-09.jpg 9] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-10.jpg 10] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-11.jpg 11] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-12.jpg 12] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-13.jpg 13] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-14.jpg 14]		* The 1896 [[Arthur Krebs]] automobile English patent: [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-01.jpg page 1] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-02.jpg 2] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-03.jpg 3] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-04.jpg 4] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-05.jpg 5] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-06.jpg 6] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-07.jpg 7] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-08.jpg 8] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-09.jpg 9] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-10.jpg 10] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-11.jpg 11] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-12.jpg 12] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-13.jpg 13] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-14.jpg 14]

	~~[[Category:Automotive technologies]]~~

	[[ja:~~キャスター~~]]		[[Category:Automobiles]]
			[[Category:Automotive steering technologies]]
			[[Category:Auto parts]]

Philip rosenblum at 21:41, 28 June 2006

2006-06-28T21:41:18Z

← Older revision		Revision as of 21:41, 28 June 2006
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	[[image:caster_angle\|thumb\|300px\|right\|θ is the caster angle, red line is the pivot line, grey area is the tire]]		[[image:caster_angle.png\|thumb\|300px\|right\|θ is the caster angle, red line is the pivot line, grey area is the tire]]
	'''Caster''' (or '''castor''') '''angle''' is the angular displacement from the vertical axis of the [[suspension (vehicle)\|suspension]] of a steered [[wheel]] in a [[Automobile\|car]] or other [[vehicle]], measured in the longitudinal direction. It is the angle between the [[pivot line]] (an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint) and [[vertical]]. Car racers sometimes adjust caster angle to optimize car performance in particular driving situations.		'''Caster''' (or '''castor''') '''angle''' is the angular displacement from the vertical axis of the [[suspension (vehicle)\|suspension]] of a steered [[wheel]] in a [[Automobile\|car]] or other [[vehicle]], measured in the longitudinal direction. It is the angle between the [[pivot line]] (an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint) and [[vertical]]. Car racers sometimes adjust caster angle to optimize car performance in particular driving situations.

Philip rosenblum at 21:39, 28 June 2006

2006-06-28T21:39:53Z

← Older revision		Revision as of 21:39, 28 June 2006
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	[[image:caster_angle~~.svg~~\|thumb\|300px\|right\|θ is the caster angle, red line is the pivot line, grey area is the tire]]		[[image:caster_angle\|thumb\|300px\|right\|θ is the caster angle, red line is the pivot line, grey area is the tire]]
	'''Caster''' (or '''castor''') '''angle''' is the angular displacement from the vertical axis of the [[suspension (vehicle)\|suspension]] of a steered [[wheel]] in a [[Automobile\|car]] or other [[vehicle]], measured in the longitudinal direction. It is the angle between the [[pivot line]] (an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint) and [[vertical]]. Car racers sometimes adjust caster angle to optimize car performance in particular driving situations.		'''Caster''' (or '''castor''') '''angle''' is the angular displacement from the vertical axis of the [[suspension (vehicle)\|suspension]] of a steered [[wheel]] in a [[Automobile\|car]] or other [[vehicle]], measured in the longitudinal direction. It is the angle between the [[pivot line]] (an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint) and [[vertical]]. Car racers sometimes adjust caster angle to optimize car performance in particular driving situations.

Philip rosenblum at 21:34, 28 June 2006

2006-06-28T21:34:16Z

New page

[[image:caster_angle.svg|thumb|300px|right|θ is the caster angle, red line is the pivot line, grey area is the tire]]
'''Caster''' (or '''castor''') '''angle''' is the angular displacement from the vertical axis of the [[suspension (vehicle)|suspension]] of a steered [[wheel]] in a [[Automobile|car]] or other [[vehicle]], measured in the longitudinal direction. It is the angle between the [[pivot line]] (an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint) and [[vertical]]. Car racers sometimes adjust caster angle to optimize car performance in particular driving situations.

The pivot points of the [[steering]] are angled such that a line drawn through them intersects the road surface slightly ahead of the contact point of the wheel. The purpose of this is to provide a degree of self-centering for the steering - the wheel casters around so as to trail behind the axis of steering. This makes a car easier to drive and improves its straight line [[stability]] (reducing its tendency to wander). Excessive caster angle will make the steering heavier and less responsive, although, in racing, large caster angles are used to improve camber gain in cornering. Caster angles over 10 degrees with radial tires are common. Power steering is usually necessary to overcome the jacking effect from the high caster angle.

The steering axis (the dotted line in the diagram above) does not have to pass through the center of the wheel, so the caster can be set independently of the mechanical trail, which is the distance between where the steering axis hits the ground, in side view, and the point directly below the axle. The interaction between caster angle and trail is complex, but roughly speaking they both aid steering, caster tends to add damping, while trail adds 'feel', and returnability. In the extreme case of the shopping trolley (shopping cart in the US) wheel, the system is undamped but stable, as the wheel oscillates around the 'correct' path. The shopping trolley/cart setup has a great deal of trail, but no caster. Complicating this still further is that the lateral forces at the tire do not act at the center of the contact patch, but at a distance behind the nominal contact patch. This distance is called the pneumatic trail and varies with speed, load, steer angle, surface, tire type, tire pressure and time. A good starting point for this is 30 mm behind the nominal contact patch.

== History ==
[[Arthur Krebs]] applied the first the positive caster angle to automotive front-train in his [http://en.wikipedia.org/wiki/Image:Krebs_Boulogne_M_et_Mme_K_Auto_ACK_7_1896.jpg 1896 car] English patent : "To ensure stability of direction by means of a special arrangement of fore-carriage, that is to say, to re-establish automatically the parallelism of the two axles of the vehicle when there is no tendency to keep them in any other direction, or after a temporary effort has caused them to diverge from said parallelism. [...] The axle of the fore-carriage is situated a suitable distance behind the projection of the axis of the pivot-pin in order to ensure the stability of direction above referred to."

== See also ==
*[http://www.ozebiz.com.au/racetech/theory/align.html Camber, Caster, Toe - What does it all mean?]
* [[Camber angle]]
* [[Toe (automotive)]]
* The 1896 [[Arthur Krebs]] automobile English patent: [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-01.jpg page 1] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-02.jpg 2] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-03.jpg 3] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-04.jpg 4] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-05.jpg 5] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-06.jpg 6] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-07.jpg 7] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-08.jpg 8] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-09.jpg 9] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-10.jpg 10] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-11.jpg 11] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-12.jpg 12] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-13.jpg 13] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-14.jpg 14]

[[Category:Automotive technologies]]

[[ja:キャスター]]

← Older revision		Revision as of 14:23, 19 July 2006
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	**[[Rack and pinion]]		**[[Rack and pinion]]
	**[[Ackerman steering geometry]]		**[[Ackerman steering geometry]]
	**[[caster angle]]
	**[[Camber angle]]		**[[Camber angle]]
			**[[Kingpin]]
	* [[Toe (automotive)]]		* [[Toe (automotive)]]
	* The 1896 [[Arthur Krebs]] automobile English patent: [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-01.jpg page 1] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-02.jpg 2] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-03.jpg 3] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-04.jpg 4] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-05.jpg 5] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-06.jpg 6] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-07.jpg 7] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-08.jpg 8] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-09.jpg 9] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-10.jpg 10] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-11.jpg 11] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-12.jpg 12] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-13.jpg 13] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-14.jpg 14]		* The 1896 [[Arthur Krebs]] automobile English patent: [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-01.jpg page 1] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-02.jpg 2] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-03.jpg 3] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-04.jpg 4] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-05.jpg 5] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-06.jpg 6] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-07.jpg 7] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-08.jpg 8] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-09.jpg 9] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-10.jpg 10] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-11.jpg 11] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-12.jpg 12] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-13.jpg 13] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-14.jpg 14]