It's easy to understand why so many people confuse wheel alignment and wheel balancing. They're both necessary for a smooth ride and to extend the service life of tires, but they're not the same process.
When performing a wheel alignment, we use sensitive computerized equipment to adjust the angles of the wheels so they're perfectly parallel to each other and perpendicular to the ground. The end result is a vehicle that rolls down the road easier and uses fuel more efficiently. Proper wheel alignment also will help suspension parts last longer.
Aligning the wheels includes measuring and, if necessary, correcting three types of angles:
The angle of the wheel when viewed from the front of the vehicle
The angle of the steering pivot as seen from the side of the vehicle.
The direction the tires point, relative to each other.
Imperfections, blemishes in the rubber, and damage to a tire or rim can throw a wheel "out of balance." That means that one section of the tire or rim is heavier. When that's the case, the tire can wobble or even hop as it rolls down the road. That effect often can be heard, as well as felt in the steering wheel.
To balance a tire, we use computerized equipment that identifies where wheel weights should be applied to the rim. Those weights are used to counter-balance any heavy spots. See diagram below.
You should have your wheels balanced any time your tires are repaired or rotated.