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:
Commercial Names and Designations
Refrigerant R134a is currently available under the following
trade names:
H-FKW 134a
SUVA 134a
KLEA 134a
Note
Different trade names may be us ...
Crimping Pliers - .35-2.5mm -VAS1978/1A
The Crimping Pliers - .35-2.5mm -VAS1978/1A- or the Wiring
Harness Repair - Crimping Plier - Base Tool -VAS1978/1-2-
together with the Wiring Harness Repair - Crimping Head -
.35-2.5mm -VAS1978/1-1-, or the Wiring Harness Repair Set -
Crimping Head - 4-6 ...
How to start the engine using jump leads
Fig. 191 How to connect the jump
leads when starting vehicles without start/stop system: discharged battery Ⓐ and
battery providing assistance Ⓑ
Fig. 192 How to connect the jump
leads when starting vehicles with start/stop system: discharged battery Ⓐ and
battery providing assistance ...
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