While the wheels on your car are quite precisely engineered when they are made at the factory, there's no such thing as perfection. The wheels may not be "perfectly" round in every way, and the quantity of the alloy used in the construction may not be uniform across every surface. What can be done about this in order to ensure that you get a smooth ride?

The Effect of Daily Driving

Not only are wheels essentially imperfect when they leave the point of manufacture, but they can also pick up additional imperfections through use. In other words, when you drive down the road every day and hit a pothole or glance a curb at the side of the street, tiny imperfections can develop, and these imperfections then throw this wheel out of balance.

Driving Forces That Affect Your Wheels

Why are these imperfections so important, and why is it crucial to have a "balanced" wheel on your vehicle?

Your wheel and tyre will rotate at high speeds and under pressure. This assembly will encounter a myriad of different challenges as you drive on a variety of uneven surfaces, take corners at speed and go uphill and downhill. If things aren't balanced correctly, it can cause a rough ride and in some cases extreme vibration through your steering wheel.

This is why you need to get your wheels balanced whenever you fit new tyres as well as periodically get them checked to see whether any adjustments are needed.

Consequences of Inaction

Whenever a wheel is not perfectly balanced, that imperfection can be magnified many times due to an increase in centrifugal force at speed. This will mean that the wheel will not spin perfectly around its axis and will usually cause a lot of wear on the tyres.

The Balancing Process

A wheel and tyre combination is balanced by putting it onto a special machine at your fitter's shop. While it is possible to do this job manually, the machine is a lot more precise.

Firstly, the wheel is placed over a central spindle, and a special cone is added to make sure that it's centred perfectly. Then, the machine will turn the spindle (and tyre/wheel) at very high speed to find out whether there are any imperfections. This will be indicated on the dashboard and will direct the mechanic where to place balancing weights in order to compensate. Usually, this is directly opposite where the imperfection is located.

The Importance of Regular Checks 

It's important to remember that the wheel is being balanced with the tyre attached. The tyre does, of course, degrade over time, and as a consequence this will affect how the wheels perform in terms of balancing. This is why it's important to get your wheels balanced whenever you have a mechanic rotate your tyres or put on new ones.