Volkswagen Polo Service & Repair Manual: Tires, Rolling Noises, General Information
Rolling noise perceived by the human ear is caused by
vibrations transmitted from the noise source to the ear via the
air. |
Here we are interested in noises created by certain
characteristics of the tires as well as the effects of rolling
(noise source). |
The cause for the noise generation depends primarily on the
combination of road surface and tire. |
The surface structure and material of the road surface also
have a strong influence on the rolling noise. For example, the
noise level on a wet road is substantially higher than on a dry
road. |
The design of the tread has a great influence on the noise
generation. Tires with cross grooves at an angle of 90° are
louder than tires with grooves running diagonally. |
Small tread blocks are unstable. Due to strong deformation,
the air is excited by the rolling tires. Air vibrations occur,
which will generate noises. |
Wider tires are louder. They require more tread grooves for
water displacement. Air is displaced by these tread grooves
while rolling, which also cause air vibrations. |
Other effects which also have an influence on noise
generation: |
“Tire vibration” is the main cause of rolling noise. The
noise is generated by the excitation of the air column in the
grooves. |
“Air pumping” is the compression and expansion of air as the
contact patch comes in contact with the road surface and the
tread blocks are deformed. |
Aid to Reasoning of Rolling Noise |
Noise generation is created chiefly by tires and the road
surface. |
Influencing factors of road surface are roughness, structure
and material. |
Influencing factors for tires fall under different tire and
rim widths. A wider tire generates more noise due to its wider
contact patch than a narrower tire does, because more air is
displaced and a greater “mass” is caused to vibrate. |
A wider rim also causes the tire to have a wider contact
patch. The effects on noise generation are basically the same as
those of a wider tire. In addition, the noise suppression
characteristics of the tire can, under certain circumstances, be
negatively affected by the wider rim. |
The tire rolling noise is significantly noticeable in the
rear of vehicles with front engines, because wind and engine
noise are less audible in the back. |
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Wear spots are caused by a hard stop with locked wheels
whereby the rubber compound is abraded from the contact patch.
When the tires slide across th ...
Other materials:
Extraction System Group Classifications
At this time, A/C service units for extracting, cleaning and
filling refrigerant for motor vehicle A/C systems are available
from various manufacturers.
Group 3:
Mobile extraction and charging systems for filling
c ...
Silicone Remover
Definition:
Silicone Remover -LSW 019 000 A5-, watery
Silicone Remover -LVM 020 000 A5-
Silicone Remover, Long -LVM 020 100 A5-
Edition 02/2012
S ...
Special Connector Systems
Note
If necessary, housing securing mechanisms (secondary locks)
must be released or removed using specified tool before
releasing the contacts. Refer to
→ Chapter „Secondary Lock“.
...
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