Volkswagen Golf Service & Repair Manual: General notes on tyre noise
| Tyre noise that can be heard by the human ear is caused by
vibrations which are transmitted by the air from the source of
the sound to our ears. |
| Of interest here are the noises caused by certain
characteristics and effects while the tyres are rolling (source
of the sound). |
| The cause of the noise is largely dependent on the
combination of the road surface and tyres. |
| The structure and material of the road surface will greatly
affect tyre noise. For example, the noise level on a wet road is
much higher than on a dry road. |
| The pattern of the tyre tread also has a significant
influence on tyre noise. Tyres with transverse grooves at an
angle of 90° generate more noise than tyres with grooves running
diagonally. |
| Small tread blocks are unstable. Their highly pronounced
deformation agitates the air as the tyres roll. This creates the
air vibrations that cause tyre noise. |
| Wider tyres are louder. They need more tread channels to
displace water. When they are rolling, these tread channels
displace the air, also creating air vibrations. |
| Further effects that also influence tyre noise: |
| “Tyre vibration” is the principal cause of tyre noise. It is
caused by the columns of air in the tread channels being
agitated. |
| “Air pumping” is the compression and expansion of the air
caused by the deformation of the tread blocks as the tyre
contact patch moves along the road surface. |
| Useful information regarding tyre noise |
| Tyre noise is determined primarily by the tyres and the road
surface. |
| The roughness, structure and material of the road surface
influence tyre noise. |
| The widths of the tyre and the rim, among other things,
influence tyre noise. Due to their larger contact area, wider
tyres will cause more tyre noise than narrow tyres, as more air
has to be displaced and more “mass” is agitated to create
vibrations. |
| A wider wheel rim will also cause a tyre to have a wider
contact patch. The effect on tyre noise is thus very similar to
that of a wider tyre. Moreover, the damping characteristics of
the tyre may also be adversely affected by the wider wheel rim. |
| On vehicles with a front-mounted engine, tyre noise is more
perceptible at the rear of the vehicle, as wind and engine
noises are not as loud there. |
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Flat spots can result from an extreme brake application
which causes the wheels to lock, so that the rubber is worn off
at the contact patch between the tread and the ...
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Rolling noise
Flat spots (from locking wheels)