4.1.11. Unilateral deterioration
The reason of unilateral deterioration in many cases is style of driving, but sometimes and wrong adjustment of corners of installation of wheels.
The raised lateral deterioration
|Fig. 4.6. An example of lateral deterioration of tyres
Lateral deterioration, more often in a combination to attritions on edges of a protector and thin cuts, arises always when tyres work at extremely big coal of lateral withdrawal, and consequently "tinder" on a road covering (fig. 4.6
Fast driving on sites abounding with turns results in particular on external shoulders of the tyre in the raised deterioration.
The rounded off external shoulder of the tyre together with high degree of deterioration of external blocks of a protector speaks about fast driving in bends. Such deterioration turns out because of corresponding style of driving.
For optimisation of rideable qualities the running gear is adjusted on certain parametres of a convergence and disorder of wheels. If tyres are maintained under the distinct from set conditions, it is necessary to reckon with the unilateral and raised deterioration.
Especially wrong parametres РУУК can lead большему to unilateral deterioration, danger of non-uniform deterioration besides increases.
Distance between wheels in front – A more than distance B behind (C a movement direction).
Convergence or positive convergence
|Fig. 4.8. A convergence or a positive convergence
The distance between wheels in front A is less, than distance B behind (C a movement direction).
To avoid unilateral deterioration of tyres, it is necessary watch that corners of installation of wheels always were in limits of the admission of a motor-car manufacturer. More often corners of installation of wheels deviate nominal parametres because of external influence, for example rigid contact to a border at a parking.
At РУУК it is possible to define, whether there are corners of installation of wheels within the admission or it is necessary to adjust them.
Changes in a running gear
Use of "the complete set of the truncated springs» and-or легкосплавных the disks which have been not admitted Audi, can lead to corners of installation of wheels which differ from put by a design.
Even if corners of installation of wheels during РУУК at the motionless car in norm, because of the changed height and position of wheels during movement character of movement of a suspension bracket of wheels can change.
Thus, non-uniform deterioration is preliminary programmed.
Deterioration of the central part of a protector
The given character of deterioration is shown on driving wheels of cars with powerful engines which often take place long distances at great speed.
At high speeds diameter of the tyre at the expense of centrifugal force increases in the middle of a protector more than along the edges. Thereof the motive power is transferred on a road cloth from an average part of a protector. This fact is reflected in turn in character of deterioration.
It is especially appreciable such deterioration it is shown on wide tyres.
Air pressure decrease in tyres to avoid such deterioration it will not be possible.
For the safety reasons at all it is not necessary to reduce pressure of air in tyres below the ordered.
More or less uniform deterioration it is possible to reach at the expense of timely shift of wheels from the leader on неприводную an axis.
The raised deterioration of a protector
|Fig. 4.9. The raised deterioration of a protector
Typical picture of deterioration of the tyres established on driving wheels of the car with the powerful engine (fig. 4.9
Bolshy deterioration of an average part of a protector of tyres is a consequence of the loadings arising because of centrifugal force of the tyre and transfer of motive power on a road cloth.