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:
Tread depth and wear indicators
Fig. 147 Tyre tread: wear indicators
First read and observe the introductory information
and safety warningsTread depth
Difficult driving situations demand the deepest possible tread depth for the
tyres and the same tread depth for the tyres on the front and rear axles. This applies
in pa ...
Stowage
Fig. 161 In the luggage
compartment underneath the floor covering A: Spare wheel and vehicle toolkit
without ball coupling, B: Spare wheel and vehicle toolkit with ball coupling, C:
Spare wheel and vehicle toolkit without ball coupling
First read and observe the introductory
information an ...
Cross-Section of a Radial Ply Tire
1 -
Tread Block
2 -
Tread Groove
3 -
Tread
4 -
Nylon Ply
5 -
Belt Layers
Consists mostly of steel
6 -
Bead Bundle
...
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Driving Noise
Wear Spots