Why Are Tires Loud Sometimes?
July 1st, 2015
Tire noise, the monotonous drone of rubber on pavement, can be the most annoying sound you ever heard. Some tires are relatively quiet and unobtrusive, some make a hypnotic hum, and others create a din so loud that makes it hard to even carry on a conversation inside the vehicle. Why are some tires so darn noisy? At Goodyear of Buckhead in Atlanta, GA, we get that question rather often.
Let’s analyze that, using a little bit of tire science and physics.
A big part of the noise level of tires is tied into “pattern noise.” The noise occurs because air is continually trapped and released in the grooves and voids of the tread itself as the tire rolls along the pavement. As a general rule, tires that have a lug or block tread pattern, as in light truck or mud-terrain tires, tend to have a noticeably higher noise level than tires with a rib or groove tread design.
Tires that have a symmetrical pattern of tread segments all around the tire tend to be noisier than tires with tread blocks of varying sizes and shapes (a “multiple pitch” pattern). The different tread segments may all set up differing pattern noises, but they tend to cancel each other out and the overall effect is a lower noise level. Grand touring tires typically are designed with a multiple pitch tread pattern.
Tires such as Bridgestone’s Turanza Serenity Plus are tuned for low noise, with specially shaped grooves that avoid the compression and release of air in the tread’s grooves, then scramble the sound waves when it does occur.
Tires that have a directional tread pattern tend to produce more noise as they wear, more so than non-directional tires.
Differing road surfaces tend to produce differing amounts of noise. Not all roads are going to have a glassy-smooth, polished concrete surface, and blacktop/asphalt, grooved concrete, and other surfaces are all going to set up different levels of noise, regardless of the tire. Figure in tar expansion strips, manhole covers, pavement joints and potholes, all of which are in abundance in Atlanta, GA, and there’s going to be a certain noise level that’s just unavoidable.
Different rubber compounds will all produce differing noise levels; as a general rule, softer tread formulations will be quieter at highway speed and tend to “absorb” more road noise.
The inflated air cavity in the tire will often resonate like a drum at highway speeds. Many tire designs, such as Pirelli’s Noise Canceling System, attempt to dampen that resonance with a spongy inner strip of polyurethane that absorbs and cancels the noise and vibration.
Lastly, proper tire maintenance is important. Tire rotations at regular intervals go a long way toward ensuring even wear patterns on all four tires, and tires that are starting to wear down will always tend to be noisier than newer tires since there’s less rubber material to absorb noise.
Now we have demystified what makes tires noisy, and hopefully been able to explain it without getting too lost in the technical details. Is it time for you to consider new quieter tires? Make an appointment with Goodyear of Buckhead in Atlanta, GA and let us find a set of tires that will be the right fit for your vehicle and your needs!