4.1.18. Side withdrawal of the car

Conicity
Conicity is caused by the small shift of a protector and/or breker in relation to the geometrical middle of the tire on several tenth millimeter. Conicity is visually not noticeable and is not measured in conditions of auto repair shop.
Because of shift rigidity on an internal and external shoulder of the tire different that leads to various forces. acting on a basic surface of a wheel. Therefore the breker and a protector "rest" against a roadbed with different effort (F1, F2). As a result the cone turns out. The effort (Fk) caused by conicity can become so big depending on speed that will begin to take away the car in any party.

Fig. 4.18. Tire elements: 1 – board; 2 – shoulder; 3 – protector; 4 – metalcord breker; a – geometrical middle of the tire; b – actual position of a breker; it can be displaced inside or outside


Fig. 4.19. Forces influencing the tire: 1 – shift брекера / protector; F1 – the unequal forces operating on a basic surface of a wheel; F2 – the unequal forces operating on a basic surface of a wheel; Fk – force created by conicity



If force (Fk) on one wheel of an axis makes, for example, 50 N, on other wheel also of 50 N, and these forces also are sent to the identical party, then they are summarized. Thanks to a tire turning on a disk side withdrawal can be compensated as forces will work in that case to the opposite side.
As to determine the direction in which force caused by conicity, not considerably works by the tire what tire caused side withdrawal, it is possible only trial trips and purposeful shift of disks and tires.
The tire consists of many elements and materials which at the end of labor-intensive process of production from a part are vulcanized. Because of it various errors which can become noticeable at more or less high side efforts turn out. These efforts can be shown as well on new tires.

Unilateral withdrawal on a forward axis
The reasons of side withdrawal can be covered in a running gear. However, by experience it is known that in over 90% of complaints side withdrawal is caused by tires.

Side withdrawal at normal style of driving
The car "pulls" in any party on the direct, flat road, at the smooth movement or moderate acceleration. At the same time on a wheel the effort is felt.

Side withdrawal at strong acceleration
Side withdrawal at strong acceleration from a part is put in a design of cars with the forward drive. Various conditions of friction of the left and right wheel, including roughness of a paving (hollow). and in this regard and changeable coupling with the road, strongly influence road performance. This problem is not a guarantee case.