7.2.4. Malfunctions of wheels and tires. Ways of their elimination
The damaged wheels, as a rule, are not under repair, and are replaced with new. Only editing of small dents of a flange of a rim in a cold state without heating is allowed. After editing it is necessary to check a wheel beating. Radial and side beats of landing surfaces of a rim on the sites of a profile adjacent to the tire, should not be more than 2 mm.
Wheels with the developed fastening openings, and also with the bent disks are not allowed to operation. Worn-out openings of fastening of wheels can be made by electric welding, are smoothed out aflush with a disk and developed to diameter of 21+1 mm on diameter of an arrangement of 170 mm. Internal diameter of a disk — 130+0,2mm.
Fig. 6.18. Types of uneven wear of tires: 1 — elevated pressure; 2 — the lowered pressure; 3 — the wrong convergence of wheels; 4 — the wrong disorder of wheels; 5 — the raised beating of the brake drum; 6 — angular fluctuation of forward wheels
The increased and uneven wear of a protector of tires, as a rule, is caused by violation of norms of their operation or abnormal work of knots of a running gear of the car and steering. It is possible to determine the reason causing wear (fig. 6.18) by the nature of wear of a protector. So, on the tire 1 the wear caused by long driving with elevated pressure, and on the tire 2 — with lowered is shown.
Wear of the tire 3 with the characteristic rounded edges on the one hand of the drawing of a protector and sharp with another is caused by violation of a convergence of wheels. At rough deviations (10 — 15 mm) from the recommended convergence of the tire less than 1000 km can be worn-out after the run.
The tire 4 has uneven wear of a protector owing to violation of disorder. Especially it is shown at a big difference in disorder of the right and left wheels.
Wear 5 in the form of one or two "bald heads" appears as a result of the raised beating of a working surface of a disk or the brake drum. Less pronounced "bald head" can appear as a result of emergency braking on the concrete highway.
On the tire 6 the spotty wear appearing at big angular fluctuations of forward wheels or one wheel concerning an axis шкворня is visible. Main reasons for spotty wear of tires following: a side play in hinges of steering drafts or in the steering mechanism, faulty operation of forward shock-absorbers or one of them, gross violation of balancing of forward wheels, weakening of fastening of levers of a steering trapeze to rotary fists, bipods on a shaft, the steering mechanism to a longeron of a frame and other reasons causing angular fluctuation of wheels.
Ways of repair of the damaged and worn-out tires are well-known and are, as a rule, carried out at the shinoremontny plants.