Automotive Alignment Angles Camber Caster Front toe Rear
Automotive Alignment Angles Camber Caster Front toe Rear toe Courtesy of Hunter Engineering Company
Primary Alignment Angles u. Front Camber u. Rear Camber u. Caster u. Front Toe u. Rear Toe Courtesy of Hunter Engineering Company
Camber u Definition: – The inward or outward tilt of the top of the wheel as viewed from the front. Typical Range: – Front camber – Rear camber - 0º ± 1º -. 5 º ± 1 º Courtesy of Hunter Engineering Company
Zero Camber u Wheel is vertical when viewed from the front u Measured degrees as Zero u Applicable to front and rear tires Courtesy of Hunter Engineering Company
Reasons to use at or near Zero Camber u Extremely wide tires u Positive offset rims u Extended Tire life Courtesy of Hunter Engineering Company
Positive Camber u Top of tire leans outboard at the top when viewed from the front u Measured degrees in u Primarily used on front wheels Courtesy of Hunter Engineering Company
Reasons to use Positive Camber u Places load inboard on spindle u Increases road u Increases directional isolation stability Courtesy of Hunter Engineering Company
Negative Camber u Top of tire leans inboard at the top when viewed from the front u Measured degrees in u Primarily used on rear wheels Courtesy of Hunter Engineering Company
Reasons to use Negative Camber u Places load outboard on spindle u Increased ability cornering u Increases road shock & component wear Courtesy of Hunter Engineering Company
Outside Shoulder Wear due to Excessive Positive Camber Angle Courtesy of Hunter Engineering Company
Camber may cause a Pull u Cross camber is the side-to-side difference in camber measurements u More than 1/2º difference side-to side may cause the vehicle to pull to the wheel with the most positive camber. Courtesy of Hunter Engineering Company
Excessive Cross Camber 0º camber 1º camber Vehicle may pull to side of most positive camber Courtesy of Hunter Engineering Company
Camber Specifications u Preferred Specs Front = 0º Rear = -. 40º u Tolerance Front = 1º Rear =. 75º u Cross camber. 70º Courtesy of Hunter Engineering Company
Exception to the rule Courtesy of Hunter Engineering Company
Front Caster u The Forward or Rearward Tilt of the Steering Axis as viewed from the side 1º to 6 º positive Typical Range u Typical tolerance ± 1º Courtesy of Hunter Engineering Company
Steering Axis Line drawn between the two pivot points of the steering knuckle Courtesy of Hunter Engineering Company
Zero Caster u Steering Axis is vertical as viewed from the side and measured as 0º Courtesy of Hunter Engineering Company
Negative Caster u Forward tilt of the Steering Axis as viewed from the side and measured in degrees Front Courtesy of Hunter Engineering Company
Positive Caster u Rearward tilt of the Steering Axis as viewed from the side and measured in degrees Front Courtesy of Hunter Engineering Company
Benefits of Positive Caster u Helps to return wheels to straight ahead after being steered u Helps to maintain directional stability Weight must be picked up as spindle turns downward …. Courtesy of Hunter Engineering Company
Negative effects of Excessive Positive Caster u Excessive steering effort & road shock u Shimmy due to excessive speed of wheels returning to center u Steering damper used to control speed of steered wheels returning to center Dampner Courtesy of Hunter Engineering Company
Caster Measurement u The amount of camber change during a 10° steer to the left & right Courtesy of Hunter Engineering Company
Tire wear factor of Caster u Tires may show wear on both outer edges due to camber roll. u Camber roll - the change in camber during a turn due to caster u The amount of camber change is relative to the amount of positive caster Courtesy of Hunter Engineering Company
Camber Roll u Left spindle down - right spindle up u Left spindle up - right spindle down Courtesy of Hunter Engineering Company
Caster may cause a Pull u Cross caster is the side-to-side difference in caster measurements u More than 1/2º difference side-to side may cause the vehicle to pull to the wheel with the least positive caster. Courtesy of Hunter Engineering Company
Cross Caster = Left caster minus right caster 2º caster 1º caster Vehicle may pull to side of least positive caster Courtesy of Hunter Engineering Company
Caster Specification u Preferred Spec Front 3. 80º Rear n/a u Tolerance Front 1º u Cross caster. 85º Courtesy of Hunter Engineering Company
Review u Purpose of Alignment Angles u Camber ê ê ê Definitions Measurement method Specification Tire wear factor Pull factor Courtesy of Hunter Engineering Company
Review u Caster ê ê ê Definitions Measurement method Specification Tire wear factor Pull factor Courtesy of Hunter Engineering Company
Front Toe Angles u Incorrect cause: front toe angles may – outside shoulder wear – inside shoulder wear – wandering – darting u Total toe changes as the speed of the vehicle increases Courtesy of Hunter Engineering Company
Total Toe u The difference in the distance measured between lines drawn through the center of tires on the same axle. u Measurements are taken at the front and rear of the tires. Courtesy of Hunter Engineering Company
Zero Total Toe u Equal distance when measured across the front and the rear of tires on the same axle. Courtesy of Hunter Engineering Company 80”
Toe-In u Measured distance is shorter between the front of the tires. 79” é front = 79 in. é rear = 80 in. Total toe-in = 1 in. 80” Courtesy of Hunter Engineering Company
Excessive Toe-In Tire Wear Outside shoulder wear Center of car Courtesy of Hunter Engineering Company
Toe-Out u Measured distance is shorter between the front of the tires. é front = 80 in. é rear = 79 in. Total toe-out = 1 in. Courtesy of Hunter Engineering Company 80” 79”
Excessive Toe-Out Tire Wear Inside shoulder wear Center of car Courtesy of Hunter Engineering Company
Total Toe Angle u The Total toe may also be displayed as an angle and expressed in degrees. Courtesy of Hunter Engineering Company Total toe angle
Total Toe Specification u Negative number indicates Toe-Out u Positive number indicates Toe-In Courtesy of Hunter Engineering Company
Individual Toe u Front individual toe is responsible for steering wheel position Courtesy of Hunter Engineering Company
Front Individual Toe formed by the intersection of the geometric centerline and a line drawn through the center of the wheel Courtesy of Hunter Engineering Company toe angle Centerline u Angle Left Front Individual toe angle
Rear Individual Toe Rear individual toe is responsible for: u tire wear u thrust angle u vehicle tracking Courtesy of Hunter Engineering Company
Rear Tire Wear Patterns u Toe-In – Outside shoulder u Toe-Out – Inside shoulder u Diagonal Wipe – a condition that may result on rear tires with excessive toe Diagonal Wipe Courtesy of Hunter Engineering Company
Geometric Centerline u. A line drawn between the midpoint of both the front and rear axles. Courtesy of Hunter Engineering Company
Thrust Line u The bisector of rear total toe. Also described as the direction the rear wheels are pushing the vehicle. Courtesy of Hunter Engineering Company
u Thrust Angle - formed by the intersection of the geometric centerline and the thrustline ( a line bisecting rear total toe ) Thrustline Thrust angle Geometric Centerline Courtesy of Hunter Engineering Company
Positive & Negative Thrust Angle Positive Thrust Angle is to the Right Negative Thrust Angle is to the Left + Courtesy of Hunter Engineering Company
Dog Tracking u. A visible dog track condition will be present, if the thrust angle is excessive. Courtesy of Hunter Engineering Company
Review u Front total toe is responsible for tire wear factors: – excessive toe-in = v outside shoulder wear v darting – excessive toe-out = v inside shoulder wear v wandering u Front individual toe is responsible for steering wheel position Courtesy of Hunter Engineering Company
u Thrustline: the direction the rear wheels are pointing the vehicle ê bisector of the total toe angle u Thrust Angle: the angle formed by the intersection of the geometric centerline and the thrustline u Rear tire wear patterns: ê outside or inside shoulder wear ê diagonal wipe if the toe angle is extreme Courtesy of Hunter Engineering Company Main Menu
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