Alignment basics
This service measures and adjusts angles that affect vehicle handling and tire wear.
What is a wheel alignment?
These angles update instantly on the alignment machine when changed.
What are live angles?
This angle helps the vehicle return to straight ahead after a turn and improves straight-line stability.
What is caster?
This angle is considered a major tire-wearing angle and can create feathered tire wear.
What is toe?
This should always be performed before measuring or adjusting alignment angles.
What is a pre-alignment inspection?
These three primary angles are commonly adjustable on many vehicles.
What are caster, camber, and toe?
Camber, toe, and thrust angle are examples of these because the alignment machine displays changes instantly.
What are live angles?
A vehicle with unequal front camber will generally pull toward this side.
What is the side with the most positive camber?
Excessive positive camber usually wears this part of the tire.
What is the outside shoulder?
On a four-wheel alignment, this end is generally adjusted before the front because it affects thrust line.
What is the rear?
This angle is the inward or outward tilt of the wheel when viewed from the front.
What is camber?
Caster, SAI, and included angle are called this because changes do not display instantly and require a sweep.
What are frozen angles?
Cross-caster causes a vehicle to pull toward this side.
What is the side with the least positive caster?
Excessive negative camber usually wears this part of the tire.
What is the inside shoulder?
If total toe specification is 0.30 degrees, this is the individual toe setting for each wheel on that axle.
What is 0.15 degrees per side?
This alignment angle is the difference in distance between the front and rear of the tires on the same axle.
What is toe?
This procedure turns the wheels inward and outward so the alignment machine can calculate caster, SAI, and included angle.
What is a caster sweep?
Excessive positive caster may cause these three symptoms.
What are heavy steering, shimmy, and excessive road shock?
A positive total toe condition points both front tires inward and usually creates this type of wear pattern.
What is rough feathered wear starting on the outer shoulders?
These parts must be used carefully because attempting to adjust them while the suspension is loaded can damage them.
What are eccentrics or eccentric bolts?
These three reference lines are used to understand tracking and thrust angle.
What are vehicle centreline, geometric centreline, and thrust line?
This step corrects for the alignment sensors not being mounted perfectly square to the wheel.
What is run-out compensation?
This angle brings the point of contact more directly under the point of load and helps provide easier steering and directional stability.
What is steering axis inclination, or SAI?
When interpreting an alignment printout, these two front angles are the main contributors to pull or drift complaints.
What are front camber and front caster?
This is why a technician should not simply “set everything green” without considering customer complaint, thrust angle, steering wheel position, specification range, and tire wear.
What is because alignment diagnosis requires interpreting the whole vehicle condition, not only whether individual readings are inside specification?