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:
Battery Safety Label
Battery Safety Label
1. -
When working in the area of batteries, fire, sparks, open
flame and smoking are prohibited. Avoid sparks when working with
cables and electrical devices, and from electrostatic discharge.
Avoid s ...
Pressure Relief Valve
Caution
Non-approved tools or materials such as leak sealing
additives can cause damage or malfunctions in the
system.
Only use tools and materials approved by the
manufactu ...
Diagonal Washouts
Diagonal wear spots on tires
Diagonal wear spots run at an angle of approximately 45°
with respect to the plane of circumference.
They usually occur once, but may also occur several times
along the tire circumference.
...
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