Noise characteristics of used summer tires

What we actually hear at speed and why used tires are not the best here

Tire noise consists of three layers. The first is mechanical rumble, which is the vibrations of the carcass from contact with asphalt micro-roughness. The second is aerodynamic whistling, when air escapes from the tread grooves, forming turbulent jets. The third is resonance in the wheel cavity, where sound is reflected between the tire, disc, and fender. In new tires, the central grooves and sipes are sharp, so they cut the air with a "scream", while in tires with mileage, the edges are slightly rounded and generate a softer tone. However, on the other hand, thinner rubber transmits more carcass vibrations to the body, especially if the tire has lost some of the plasticizers and has become stiffer. Therefore, the result is not unambiguous: silence or rumble depends on which noise component will prevail after wear.

How was measured: ISO 10844 stand and field tests "Eurowheel"

The laboratory stage was carried out on a drum stand "SilentRoll-3" with a certified coating that simulates asphalt with an average roughness MPD of 0.5 mm. The tires were mounted on a 7J-16 alloy wheel, inflated to 2.3 bar and driven in two series: warm-up at 20 km/h, then stabilization at 90 km/h for 60 seconds. A Brüel & Kjær microphone, fixed in the center of the drum, recorded A-noise in octave bands. After the laboratory, road measurements were conducted: a VW Golf VII car with the noise-absorbing mats removed so that the bodywork would not "mask" the difference. The Rion NL-52 recorder was attached to the back of the rear seat. All measurements were made on the Kyiv - Obukhiv concrete road section (roughness is higher than on the drum); measured noise at 50, 90 and 120 km/h.

Measurement results: numbers you can hear in the cabin

Tire model	Tread remaining, mm	Stand, dBA		Real road, dBA
		90 km/h	Tonality*	50 km/h	90 km/h	120 km/h
Michelin Primacy 4	6.5	70.8	low «hiss»	59.2	66.1	70.4
Continental EcoContact 6	6.2	71.6	average "Shurhit"	60.0	67.3	71.9
Pirelli Cinturato P7	5.8	72.9	average "hum"	60.8	68.5	73.8
Goodyear EfficientGrip Perf.	5.5	74.1	tall «buzz»	61.7	69.4	75.2

*Tonality — a qualitative description of what the ear hears: «hiss» from turbulent air or « hum» of the carcass. In practice, a difference of 3 dBA is perceived by a person as a noticeable increase in loudness. The «color» of the noise also becomes more noticeable: Michelin retained a soft ’hiss» after wear without resonances, and Goodyear gave a distinct high-pitched whistle at 120 km/h due to the sharp edges of the shoulder blocks that had not yet worn out.

What increases noise and how to tame it without changing tires

1. Pressure: underinflation by 0.2 bar increases the resonance of the frame, adding 1-1.5 dBA.
2. Disturbed camber-toe: uneven wear of the blocks generates a rumble that can be heard already at 70 km/h.
3. Luggage weight: an additional 100 kg shifts the frequency of the wheels' natural vibrations and generates a hum of the rear axle.
4. Spare part cavity: fill the space with soundproofing mat — it dampens up to 2 dBA of body resonance.
5. Hole in the fenders: sew up the "torn" mudguards, and the air turbulence will disappear along with 1 dBA of whistle.

How "Eurowheel" selects kits and guarantees silence in the cabin

At the selection stage, all tires undergo a short "acoustic rental" on a stand at 90 km/h. If the noise level exceeds 73 dBA or the spectrum contains two distinct peak harmonics (meaning resonance in the shoulder blocks), the kit is rejected or sold at a discount for those for whom noise is not critical. Before sending to the customer, the manager will send an audio file of a 10-second track from the laboratory upon request to assess the tonality. So the buyer receives not only a DOT passport and tread remaining, but also measured silence. In short, the difference between a quiet and a loud used set reaches 5 dBA - this is the level that determines whether you will communicate in a calm voice in the cabin or raise your voice after 90 km/h. Check the tread remaining, listen carefully to the "color" of the noise on a test driveand don't hesitate to ask the seller for measurements — then even used tires will give the interior business-class comfort. At «Eurowheel» we will help you choose just such a set: quiet at speed, economical and safe in the rain. Call from 8:00 to 21:00 or stop by Saperno-Slobidska, 8 — silence on wheels is closer than it seems.