Do I Need a Tire Balance or a Wheel Alignment? What's the Difference?
Every day I hear, "My car shakes, I need my tires aligned." Or, "My car pulls to the right, I need my tires balanced." My response is always, "Well, who told you that?" . . . "My mechanic."
There is a fundamental misunderstanding between balancing tires and lining up the front end of a car. To balance a tire is completely different than lining up a car, not to mention that these maintenance services treat two totally different automotive ailments.
Here's how balancing and aligning are different, what they involve, and how to tell if your car needs one.
The Difference Between Tire Balance and Wheel Alignment
• Weights are applied to planes on the tire rim, inside and out.
• Adjusting angle of wheels, including caster (angle between upper and lower ball joints) and camber (the angle between the tire and the axle).
• Sign it's time for one: Shaking or vibrating at 60 - 70 mph.
• Sign it's time for one: Severe wear on outside or inside edge of tire.
Balancing a tire involves the application of zinc, lead, or non-lead/composite weights to each plane of the rim—the inside and the outside. However, since there are many different styles of rims, there are several different weight applications used to balance.
- The easiest and most basic way uses "pound on," inside and outside weights to the top dead center (TDC) of both rim planes.
- On a fancier rim, where an outside weight is undesirable or inapplicable, stick-on weights are carefully applied using laser guidance on the inside of the outer plane (the part of the rim that slides over the brake assembly when bolted on). One must be careful not to use too thick of a weight or it will hit the brake caliper and be ripped off. Conveniently, there are thin, quarter-ounce weights for this purpose.
- Lastly, for certain tires that require too much weight (are maybe too old and out of whack) and especially mud-terrain tires, there is the static balance. This balance involves applying a weight to TDC of the inside plane only, creating "perfect balance" when the tire is not in motion. It is a last resort and the least accurate balancing technique.
The tell-tale sign of your tires being out of balance is a shake or vibration between 60 and 70 miles per hour. Generally shaking in the steering wheel and/or seat of the vehicle are the top complaints customers come in with.
There are several different reasons tires can be out of balance. Tires, as they wear down, begin to take on a different shape than how they began. This is due to many factors, such as wear and tear on your front-end parts (ball joints, control arm bushings, tie rods, etc.), the crown of the roads, potholes, hard braking causing flat spots, throwing (losing) weights, and even poor construction of the tire (more common with "economic" tires). If you live in a snowy area or trek through mud regularly, snow and ice build-up can cause major shaking as well as the clumping of mud on and around the rim. In that case, removal of ice or mud would be necessary followed by a test drive and a re-balance if needed.
Typically, tires don't need to be re-balanced unless the customer experiences any of the shaking or vibrations associated with out-of-balance tires. Most customers prefer to balance their tires with tire rotations or oil changes. Some companies offer complimentary tire balancing with such services. Our policy is, "If it's not broke, don't fix it." In other words, if it hasn't posed a problem thus far, there is no need to waste the customer's time and money.
NOTE: Having a shake and having a wobble are two entirely different things. A wobble would be felt around take-off speed to 40 mph, indicating a bad tire. Having a "bad tire" means belts breaking inside the tire or having a tire severely out of round.
Obtaining a wheel alignment for your vehicle could be necessary for many reasons. In fact, several maintenance and repair jobs require wheel alignments when completed due to the obstruction of the caster and the camber.
- The caster is the angle between the pivot line (an imaginary line that runs vertically through the center of the upper ball joint to the center of the lower ball joint) from the front to back of the vehicle.
- Camber is the angle from the top/bottom of the tire to the axle. If the top of the tire sticks out farther than the bottom (farther away from the axle), it is a positive camber. If the bottom of the tire sticks out more than the top, it is a negative camber.
Several things indicate you should consider getting an alignment.
- Severe inside or outside edge wear on your tires is the most common.
- Your vehicle pulling to one side or the other is a sign too. However, this can also be a result of a few other things: low air pressure, tire going down, malfunctioning brakes, front-end problems, etc.
- An accident towards the rear of the vehicle or rough edge tire wear may indicate that a four-wheel alignment is necessary.
- It is suggested that one get an alignment every time the tires are replaced.
- A car may need one sooner if they there is uneven wear or if ball joints, tie rods, or suspension have been replaced.
Every car maker has a factory setting for what their specific alignment should be. Unfortunately, due to the unevenness of the environment, the crown of the roads, accidents vehicles suffer, and daily driving, factory settings can be way off. For example, Ford's older models are infamous for being toed in too much. A good alignment tech will learn these traits over the years and account for such degrees when performing the alignment.
Do you need a four-wheel alignment? Some vehicles aren't set up for four-wheel alignments. Examples are most trucks (old and new) and older cars. Anything with a single-tube axle in the rear end can only have a front-end alignment. Newer SUVs have adjustments, and most independent suspension cars will accept the four-wheel alignment. In most cases, a four-wheel alignment is unnecessary but not a bad idea.
One crucial thing to know about getting an alignment is if front-end parts are needed, the alignment should be put on hold until said parts are replaced. There is no need to pay for the alignment twice!
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.