Transportation Training Wheel Alignment

Why Align the Wheels? Correct Wheel alignment is essential to vehicle safety.  Improve Handling Ability  Maximum Fuel Economy  Prolong Tire Life By Allowing the tires to roll freely without scuffing or slipping sideways under any operating conditions

Alignment Angles and Adjustments 1.Caster 2.Camber 3.Toe-in/out 4.Ride height 5.Thrust Angle or Tracking 6.Steering Center Non adjustable 7.Scrub Radius 8.Steering Axis Inclination 9.Toe-Out on Turns

Caster Caster is the forward or rearward tilt of the Steering Knuckle When viewed from the side of the vehicle.Measured in degrees. Caster is adjustable  To increase Directional Control of the vehicle  To compensate for Road Crown Pull.  To help the wheels to return to the straight-ahead position. Positive for power steering Negative for manual steering

Camber Camber is the inward or outward tilt of the top of the wheel and tire assembly When viewed from the front of the vehicle. Measured in degrees. Camber is adjustable  To prevent tire wear on the outer or inner tread  To load the larger inner wheel bearing vs. the smaller outer bearing.(Positive)  To aid steering by placing the weight on the inner end of the spindle and reducing scrub radius. Common camber settings are ¼ to ½ degree positive

Toe-in /Toe-out Is the inward or outward direction of both left and right wheel and tire assemblies When viewed from above the vehicle. Measured in inches or millimeters or degrees. Toe-in is when the front tires are closer at the front than at the rear Common Settings: Front Wheel Drive 1/16” or 1.5 mm Rear W Drive 1/16” to ¼” or 1.6 to 6 mm

Ride Height Ride height is measured from the rocker panel to the ground surface Measured in inches or centimeters at 4 locations close to each wheel

Thrust Angle or Tracking Thrust angle is the direction that the rear wheels are pointing in relation to the center line of the vehicle. Thrust angle should be zero and is only adjustable on certain vehicles.

Steering Wheel Center Steering center is simply the fact that the steering wheel is centered “level” when the vehicle is traveling down a straight and level road. Adjusted by toe settings and affected by thrust angle.

Common Adjustments The most common adjustments are Caster, Camber, Toe, and Thrust angle

Pre Alignment Inspection  Worn Tires  Tire Pressure  Tire Size and Type  Wheel or Tire runout  Cradle Alignment  Loose Wheel Bearings  Ride Height and Weight  Worn Steering and Suspension Components Tech Tip: Always Road test the vehicle before doing a wheel alignment. This helps to detect problems, like pulling or worn components.

Reading Tire Wear Reading Tire Wear Abnormal Tire Wear is Caused by  Incorrect Tire Pressure  Excessive Camber  Incorrect Toe Settings  Lack of Rotation  Unbalanced Tire  Under Rated Tires  Driving Conditions

Making Adjustments Caster is adjusted by moving the control arm so that the ball joint moves toward the front or rear of the vehicle and is not always adjustable.

Making Adjustments Camber is changed by moving the control arm in or out without moving the ball joint forward or rearward..

Making Adjustments Toe angle is adjusted by lengthening or shortening the tie-rods...

Suspension Types Mac Pherson Strut Suspension with Rack and Pinion Steering Conventional Suspension & Parallelogram Steering

ASE-Type Questions Automotive Service Excellence Chapter 74

Transportation Training Wheel Alignment The End