Wheel alignment vs tire balancing: what each fixes

An alignment adjusts the suspension, not the tires, to bring the wheel angles back to the vehicle maker’s specifications. The U.S. Tire Manufacturers Association (USTMA) explains why it matters for tires: misaligned wheels stress the tires as if the car were always cornering, which wears them faster and unevenly. Three angles do most of the work:

The rear wheels matter too. Their direction sets the car’s “thrust angle”, and if the rears point slightly to one side, the steering wheel ends up off-center even when the front is set correctly. Nissan tells its technicians the rear thrust angle should be close to zero. USTMA says front-wheel-drive cars and cars with independent rear suspension need all four wheels aligned, not just the front.

No tire and wheel is perfectly even. Where one area is heavier, the assembly bounces or wobbles as it turns. A balancing machine spins it to find the heavy spots, and the shop clips or sticks small weights to the wheel to offset them. USTMA describes two kinds of imbalance, and both cause vibration at highway speed:

Automakers define a pull more strictly than most drivers do. Toyota’s test is to drive 100 meters straight at 35 mph without steering: drifting more than 5 feet sideways is a pull, 5 feet or less is within spec. Nissan uses a lane change at 60 mph on a nearly flat road. An off-center steering wheel is a separate problem, where the car goes straight but the wheel is turned, and Nissan says to fix any pull first because that may fix the wheel too.

The angles explain the direction. A car pulls toward the side with more positive camber and toward the side with less positive caster. Toyota says side-to-side differences of 0.5° or less in camber or caster won’t cause a noticeable pull.

Imbalance shows up as vibration at highway speed, often only within a certain speed range. Automaker bulletins give examples such as 55 to 80 mph (Audi) and 65 to 70 mph, the most common tire complaint in one GM bulletin. Where you feel it tells you which end of the car to check: GM and Audi both say a shake in the steering wheel points to the front wheels, and a shake in the seat or floor points to the rear.

Michelin notes that uneven wear like this usually can’t be undone once it has set in. Correcting the cause protects the next set. USTMA says to find and fix misalignment or imbalance before a tire rotation, or the problem simply moves to another wheel.

Before paying for an alignment to fix a pull, rule out the tires. Every radial tire generates small sideways forces, and Toyota says one of them, conicity, created by uneven forming of the tire’s two sides, is most often the biggest. Toyota’s test is simple: swap the front tires from left to right. If the pull reverses or disappears, a tire is the cause. If nothing changes, look at the alignment.

Toyota goes further, warning that aligning a car to cure a tire pull can push the alignment out of spec and cause uneven wear. Other common causes of a pull or vibration:

Tires should be balanced every time they’re mounted on a wheel, which includes buying new tires and having a tire removed for a repair. Michelin also suggests a balance check if a weight comes off or a new vibration appears between tire changes, since wear gradually changes the balance.

USTMA says to check alignment as your owner’s manual specifies or whenever you suspect a problem. Michelin and Goodyear suggest about once a year as a baseline. Beyond that, get it checked:

Lane-keeping and automatic emergency braking rely on cameras and radar that need to know which way the car is actually travelling. If an alignment changes the thrust angle or the steering angle sensor’s idea of straight ahead, those systems can work against a car that is already tracking straight. Whether you need a recalibration depends on the vehicle:

Every major tire warranty we reviewed excludes wear caused by the vehicle: misalignment, imbalance and worn suspension parts. Bridgestone lists shoulder wear, center wear, cupping and feathering as irregular wear it won’t cover, and says keeping alignment and balance correct is the owner’s job. Continental excludes “wear due to improper vehicle alignment”.

Vibration and pull complaints are covered only early. Bridgestone and Goodyear stop covering ride complaints once the tread is worn past the first 2/32 inch, and Continental after 2/32 inch or 12 months. Michelin, Bridgestone and Goodyear also exclude tires that have balancing beads or liquids added after the factory. If a new set of tires vibrates or pulls, raise it with the installer right away. Our tire warranty guide covers the rest of the fine print.