Here is some information that we think will help you understand wheel alignment and associated problems.

  • Caster

    Definition:

    Forward or backward tilt of king pin or spindle support arm at the top. Measured in degrees positive or negative.

    Influence on Vehicle Handling:

    Too little causes high-speed instability and poor directional stability such as wandering. Too much causes hard steering, excessive road shock, and shimmy through the steering wheel.

    Influence on Tire Wear:

    Usually not a factor in tire wear.

  • Camber

    Definition:

    Inward or outward tilt of wheel at the top. Outward is positive, inward is negative. Measured in degrees positive or negative.

    Influence on Vehicle Handling:

    Excessive camber (negative or positive) will cause vehicle to pull to the side with greatest variance.

    Influence on Tire Wear:

  • Toe In / Toe Out

    Definition:

    Amount that front of wheels is closer together than rear of wheels. For radial tires, toe should be as close to “0” as possible when vehicle is running. Measured in inches.

    Influence on Vehicle Handling:

    May cause vehicle to track improperly and steering wheel to be off centered.

    Influence on Tire Wear:

    Toe In Tire Wear:
    Toe Out Tire Wear:

    Incorrect toe will cause a feather-edge wear pattern across the tire tread that can be felt as you slice your hand across the tread.

  • Steering Axis Inclination

    Definition:

    Inward tile of spindle support arm or king pin at the top. Directional control angle measured in degrees that spindle support center line is tilted from true vertical.

    Influence on Vehicle Handling:

    Non-adjustable angle that, with camber, controls “scrub radius” to minimize effects of road bumps on steering.

    Influence on Tire Wear:

    Rapid tire wear can result from mounting new wheels with different offset that may increase scrub radius by moving tire footprint outside projected pivot point.

  • Toe-Out In Turns

    Definition:

    Amount that front wheels tow out during turns. Ideal angle reduces tire scrubbing. Measured in degrees.

    Influence on Vehicle Handling:

    Does not influence vehicle handling qualities..

    Influence on Tire Wear: