Caster basics
This alignment angle is viewed from the side of the vehicle and describes the forward or rearward tilt of the steering axis
What is caster
Caster, SAI, and included angle are called this type of angle because changes are not instantly displayed on the alignment machine
What are frozen angles
This condition exists when caster is different from side to side
What is cross-caster?
Positive caster increases the vehicle’s tendency to do this while driving
What is go straight
Excessive positive caster can cause this steering feel
What is heavy steering
This type of caster occurs when the top of the steering axis tilts forward from true vertical
What is negative caster
This procedure must be performed to measure caster, SAI, and included angle
What is caster sweep
A vehicle will pull toward the side with this caster condition
What is the least positive caster?
This distance increases as caster becomes more positive
What is caster trail
Excessive negative caster can cause this highway-speed problem
What is instability at high speeds
This type of caster occurs when the steering axis is vertical
What is zero caster
During a caster sweep, the alignment machine calculates caster by comparing this angle while the wheel is turned inward and outward
What is camber
On a road crowned to the right, the vehicle naturally tends to lead this direction
What is toward the curbside/right
As positive caster increases, steering effort generally does this
What is increases
Excessive negative caster can cause these two driving complaints because of reduced directional stability
What are wander and weave
This type of caster occurs when the top of the steering axis tilts rearward from true vertical
What is positive caster
This device should be used during a caster sweep to prevent vehicle movement and help avoid restarting the measurement
What is a brake pedal depressor
To offset right road crown, some manufacturers recommend setting this side slightly more positive
What is right side
Caster helps the steering wheel do this after a turn
What is return to center
Excessive positive caster may create this rapid side-to-side movement of the wheel
What is shimmy
Caster belongs to this classification of steering angles
What is directional control angle
After changing caster, the technician must do this before trusting the updated caster reading on the alignment screen
What is a caster sweep
A vehicle has LF caster at +2.0° and RF caster at +4.5°. Based on caster alone, the vehicle will likely pull this way
What is left side
Positive caster helps returnability because turning the wheels causes one side of the vehicle to lift slightly, and this force pushes the vehicle back down
What is vehicle weight/gravity
Caster does not directly affect tire wear, but it can contribute to this effect during turns because caster:
What is changes camber as wheels turn