Toe (automotive)

In automotive engineering, toe is the symmetric angle that each wheel makes with the longitudinal axis of the vehicle, as a function of static geometry, and kinematic and compliant effects. This can be contrasted with steer, which is the antisymmetric angle, i.e. both wheels point to the left or right, in parallel (roughly). Positive toe, or toe in, is the front of the wheel pointing in towards the centreline of the vehicle. Negative toe, or toe out, is the front of the wheel pointing away from the centreline of the vehicle. Toe can be measured in linear units, at the front of the tire, or as an angular deflection.

In a rear wheel drive car, increased front toe in ("i.e." the fronts of the front wheels are closer together than the backs of the front wheels) provides greater straight-line stability at the cost of some sluggishness of turning response, as well as a little more tire wear as they are now driving a bit sideways. On front wheel drive cars, the situation is more complex.

Toe is always adjustable in production automobiles, even though caster angle and camber angle are often not adjustable. Maintenance of front end alignment, which used to involve all three adjustments, currently involves only setting the toe; in most cases, even for a car in which caster or camber are adjustable, only the toe will need adjustment.

One related concept is that the proper toe for straight line travel of a vehicle will not be correct while turning, since the inside wheel must travel around a smaller radius than the outside wheel; to compensate for this, the steering linkage typically conforms more or less to Ackermann steering geometry, modified to suit the characteristics of the individual vehicle.

It should be noted that individuals who decide to adjust their car's static ride height, either by raising or lowering, should immediately have the car properly aligned. The common misconception is that Camber angle causes an increased rate of tire wear, when in fact camber's contribution to tire wear is usually only visible over the entire life of the tire.Fact|date=June 2008

ee also

*Caster angle
*Camber angle

External links

* [http://www.ozebiz.com.au/racetech/theory/align.html Camber, Caster, Toe - What does it all mean?]
* [http://www.240edge.com/performance/tuning-toe.html Toe and Race Car Suspension Tuning]


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Look at other dictionaries:

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  • Toe (disambiguation) — Toe or TOE or similar can refer to: * Toes, the digits of the foot of a human or animal * Toé , a common South American name for Datura and related plants * Toe (automotive), or Toe in, the angle that each wheel makes with the longitudinal axis… …   Wikipedia

  • toe-out — An adjustment of the wheels where the front of the wheels is further apart than the back. Generally toe out is not desirable. Toe out is measured in fractions of an inch or millimeters. See toe in …   Dictionary of automotive terms

  • toe-in — An adjustment of the front wheels where the distance from the center of the left wheel to the center of the right wheel is less at the front of the wheels than at the back of the wheels. A slight amount of toe in is usually specified to keep the… …   Dictionary of automotive terms

  • toe in — See toe in …   Dictionary of automotive terms

  • toe out — See toe out …   Dictionary of automotive terms

  • toe out on turns — See toe out on turns …   Dictionary of automotive terms

  • toe-out on turns — When the vehicle negotiates a curve, the inner wheel turns more sharply and while the wheels remain in this position, a condition of toe out exists …   Dictionary of automotive terms

  • toe steer — The changes in the direction of a wheel that occur without driver steering input. Toe steer can be caused by ride steer or by deflections in suspension components caused by the stresses of cornering, accelerating, and/or braking on smooth and… …   Dictionary of automotive terms

  • toe wear — See heel and toe wear …   Dictionary of automotive terms


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