What alignment actually is
Alignment is the set of angles at which the wheels sit relative to the road and to each other. The three that matter are:
- Toe, whether the wheels point slightly inward or outward. Of the three, this is the one that scrubs tread off at the greatest rate when it is wrong.
- Camber, the inward or outward lean of the wheel at the top. Wrong camber wears one edge of the tire.
- Caster, which affects steering feel and straight-line stability rather than wear.
Those angles move. Potholes, curb strikes, worn suspension components and plain age all shift them, and the vehicle rarely announces it.
How you know
- The vehicle pulls to one side on a flat, straight road.
- The steering wheel sits off center while driving straight.
- Tires wear on one edge, or feather across the tread.
- The steering feels vague or wanders.
- You have just hit something hard, or had suspension work done.
The wear pattern is the most reliable of those, because it is physical evidence rather than a feeling. A tire worn on the inside edge is a diagnosis, not a complaint.
When to have it done
When fitting new tires, before they go on. Fitting first means the new set starts correcting whatever killed the last one.
After suspension or steering work, because replacing those components changes the geometry.
After an impact hard enough to be worth remembering.
When the wear says so, which is why a store looks at the old tires when it takes them off.
What it protects
- Tire life, which is the direct saving and often a large one.
- Fuel, since misaligned wheels drag rather than roll.
- Handling and safety, because a vehicle that tracks properly is a vehicle that responds predictably.
- Suspension components, which are loaded unevenly when the geometry is wrong.
Alignment, balancing and suspension
Three services, three different problems, and they get confused constantly:
- Alignment fixes pulling, crooked steering and uneven wear.
- Balancing fixes vibration at speed.
- Suspension repair fixes the components that hold the geometry in the first place. Worn parts will not hold an alignment, which is why a store checks them before aligning.
A good store will tell you when the alignment is not the problem, and that conversation is worth more than the alignment itself.
For trucks and fleets
Pickups and vans in a working fleet get aligned on a schedule through fleet services, alongside the heavier units. For tractor units and trailers, the service is heavy-duty truck alignment at 40 locations and trailer alignment at 36.