4.1.8. Service of tires

Air pressure in the tire
The mass of the car flattens the tire on the area of its contact with the road. Leads Kacheny tires to compulsory deformation of a protector and all breker. With an insufficient pressure the compelled deformation increases owing to what temperature and resistance to swing increases. These factors lead to the increased wear and negatively influence traffic safety.
Too high pressure of air in the tire results in the increased wear of a middle part of a protector and worsens comfortableness. It is always recommended to support the air pressure in tires specified by the producer.

NOTE
The provided schedules do not extend to all scale of production.
They are necessary to show wearability of tires on forward and back axes, and also wearability of tires on cars with the forward and four-wheel drive.


Depending on service conditions and a running gear achievable service life of tires can deviate strongly from given below.

Fig. 4.3. Schedule of 1 wearability of tires



Height of the drawing of a protector throughout service life for cars with the forward drive and tires with an index of speed of V.
P – Height of the drawing of a protector.
S – Run.
1 – Forward axis.
2 – Back axis.

Fig. 4.4. Schedule 2 wearabilities of tires



Height of the drawing of a protector throughout service life for cars with the four-wheel drive and tires with an index of speed of V.
P – Height of the drawing of a protector.
S – Run.
1 – Forward axis.
2 – Back axis.
Apparently from schedules 1 and 2, the tire with the full drawing of a protector during the certain run wears out more, than much more worn-out tire. After the first 5000 km it is impossible to judge total period of service of the tire as the characteristic of wear passes not linearly.
On front-wheel cars forward wheels, except efforts at turns and dispersal, are forced to maintain the most part of side and brake efforts. Because of such loadings of the tire on forward wheels of front-wheel cars wear out much quicker, than on back wheels. Uniform wear of all tires is reached due to regular shift of forward and back wheels.