What Is The Difference Between Wheel Alignment And Wheel Balancing?
Wheel balancing is probably the most underrated service in the automotive industry. Even more, few services generate as much debate among car owners and enthusiasts as wheel balancing does. What is the cause of that?
Most of the confusion and debate revolves around the misconception that wheel balancing and wheel alignment are almost the same. Truth is, wheel alignment is a less common service that involves adjusting front-end and suspension components to keep an optimal tire contact with the road. Nowadays, low tolerances in suspension components had made possible to reduce the need for wheel alignment significantly. It's still advisable to check wheel alignment at least once a year (or sooner if you have an issue) though.
On the other hand, wheel balancing is closely related to tire wear and/or deformation. Unlike wheel alignment, you may need to balance your wheels way more often, especially if you drive many miles a year.
Is Tire Balancing Necessary?
Wheel balancing is all about vibrations. Do you ever felt a shaky sensation on the steering wheel? If your answer is yes, chances are that you had at least one unbalanced wheel. You may wonder where do these vibrations come from. A simplified answer would be from imperfections, wear or damage.
Ideally, a tire should have a perfect cylindrical shape. Reality is, that even new tires have imperfections. Tire makers invest billion of dollars enhancing the manufacturing process, but even so, small imperfections are always present. On the other hand, wheels are not perfect either. No matter if they are cast iron, titanium alloy, you name it. Wheel also have small imperfections. Best brands manage to lower those imperfections to an acceptable minimum known as the accepted “tolerance”. Problem is, these small flaws still cause vibrations, even when they are within the accepted tolerance, and lowering more the tolerances is not an option because is too expensive. Solution? Wheel balancing.
Wheel Balancing To The Rescue
Wheel balancing became relevant to the automotive industry since the early days because it efficiently solves the vibration issue. Even today, with all the innovations and technology, wheel balancing continues offering the optimal solution. Because the problem doesn’t end with the manufacturing process. There is another factor not mentioned yet: wear.
Tires wear, that’s inevitable. And they will wear unevenly no matter how good is the suspension condition or front-end wheel alignment because the friction between the tires and the road is not distributed equally. Remember the wheels? They don’t wear as tires do but they may suffer occasional damage and deformation from bumpy roads, or even while parking if you accidentally hit the sidewalk.
What all that means is that wheel balancing will always be needed. Sooner or later you will need to balance your wheels.
What Does A Wheel Balance Do?
The main goal of balancing the wheels of a car, is to counteract the vibration produced by their inherent unbalance. This is accomplished by attaching weights (also called counterweights) to the wheels that equilibrate the tire/wheel assembly.
How much weight and where to locate it is the most important question.
Both parameters are important, the weight should be the about necessary to cancel the vibration, and can't be more or less. Regarding its location, it should be positioned at the exact opposite point of the unbalancing weight. In technical terms, when talking about “counterweight location” we are talking about a location in a tri-dimentional space.
As you may imagine, balancing a wheel isn’t something easy to do without help. There are specialized machines called “wheel balancers” that remove all of the guesswork. The wheel balancer makes it a simple job by basically indicating where you should attach the counterweight and also how many grams (or ounces) it should have.
Myths About Wheel Balancing
Wheel balancing can be a complex topic. There are lots of myths and misinformation out there in relation to it, especially when it comes to wheel balancing vs wheel alignment.
Why Is Wheel Balancing Necessary?
(Myth: New tires come balanced from the factory)
There is no way to attach a counterweight to a tire (unless you bond a patch to it) so you cannot “balance” a tire. New tires can be balanced once they are fitted to the corresponding wheel because you can attach weights to it. Believe it or not, many tires are returned to factory due to flaws that can’t be fixed with a wheel balancer (need an excessive counterweight).
That said, tires do come from the factory with a reference (usually a small circular sticker) that points its heaviest spot. Ideally, wheels also have a visual reference of its heaviest spot. A good technician always tries to assemble the wheel in a way that both references end up in opposing sides (180° from each other). If both references are located too close the amount of counterweight required can be so high that could mislead the issue as a “bad tire”.
What are the 2 types of wheel balancing?
(Myth: Static and dynamic balancing modes are equally effective)
Without diving into theory, let’s simplify the discussion saying that the static mode of a wheel balancer sees the tire as a bidimensional shape, like a disc. Results won’t be accurate. You can balance the wheel but it won’t perform optimally at high speeds. Also, you most probably will end up using too many weights affecting wheel aesthetics considerably. On the other hand, the dynamic mode sees the wheel as a tridimensional shape, like a cylinder and thus its accuracy is far better than the static mode.
You may ask if that’s true, why the wheel balancer has a static mode? And why some technicians insist that both modes do the same?
The reason behind keeping a static mode is convenience. When you use the wheel balancer in the static mode you attach all counterweights on the same side of the wheel, usually the outer side. Sometimes, even when not totally accurate, using the static mode is the right choice. For example, imagine a off-road vehicle with mud tires. Remember about tire wear? Mud tires are a nightmare in that sense. They are not designed for highway use, so there is no point in looking for accuracy at high speeds. The static mode allows balancing that kind of wheels very easy. Aesthetics, and performance at high speeds are not important for that kind of applications.
The dynamic balancing mode is another story altogether. For starters, there is more than one dynamic mode, in fact, there are many. The dynamic mode allows weight placement on both sides of the wheel (inner and outer sides). That is important not only from a performance point of view but also aesthetics. A thousand dollar wheel should not be showing counterweights. Different dynamic modes bring the flexibility to locate the weights in different positions. The downside of the dynamic balancing mode is time. The technician will need more time to find the optimal setup for your wheel. And time is money.
What Happens If Your Tires Aren't Balanced?
Besides the feeling on the steering wheel, your vehicle should be balanced to avoid other consequences. Below is the list of the most common issues you could face if driving with unbalanced wheels:
- Excessive tire wear.
- A noticeable instability that can be even dangerous.
- Excessive stress on shock absorbers.
- Excessive stress on wheel bearings.
- Excessive stress on other suspension components.