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The wear of the tire has natural wear and abnormal wear. Natural wear is a normal phenomenon in the use of tires, and the tire marks on the tire side before they go out. Some are triangular symbols. It shows that when the tread pattern is worn to this mark, the new tire should be replaced, because the draining performance and anti ligation performance of the tires will be greatly reduced at this time. Tire abnormal wear is the normal wear speed of the tire during running, and the abnormal shape of the tread. There are many forms of tire damage during normal operation, but the common form of damage is abnormal wear of tyres. It greatly shortens the normal service life of the tire. It shows that there are hidden dangers in the use of the vehicle. It should be found out according to the wear characteristics of the tire, and take effective measures to eliminate it in time to prolong the life of the tire. (1) the inner side of the tire crown is worn, showing an inner cone. The main reasons are: the car runs on the arched road for a long time, does not change the position in time, the two ends of the axle bend upward, so that the inside of the tire is too large; the angle of the front wheel is not correct. (2) wear on the outer side of the tire crown is serious, showing an outer cone, which is caused by misalignment of the wheel camber or long untransposition. In the case of regular transposition of the tires, when the lateral shoulder of the tread is badly worn, the obliquity is too large; when the inner surface of the tread is seriously worn, the obliquity is too small. (3) tire wear is serious in the middle of the crown, that is, the middle part of the tire is worn. The main reason is that the tire is working under high tire pressure for a long time, which causes the wear of the tire crown in the middle and the bottom of the pattern crack. In addition, when the vehicle is overloaded, the tire pressure will increase as the temperature inside the tire increases. (4) the two sides of the tire crown are badly worn. The main reason is that the tire pressure is insufficient for a long time, or the tire tread is too narrow, the wheels are too wide, and the tire wear is mainly borne by both sides of the tread. (5) the partial wear of the tire is serious. The main reason is that there are more emergency braking, brake drum missing, tire imbalance, tire deformation and so on. (6) the front tire of the front tire is worn into ellipse. The main reason is that the value of the front beam is incorrect and the air pressure is insufficient. (7) tread pattern wear of tires. The wheel's dynamic balance is not good or the vehicle's damping performance is poor, so that the wheels of the vehicle run too much, and the pattern of the tire appears to be porphyry. It may also be caused by the car running on the corner stone pavement for a long time. (8) the small pattern or large pattern on both sides of the tread is worn into a saw tooth. It is usually due to the instantaneous contact between the tread and the hard pavement, and the front end of the pattern block is extruded and deformed. (9) the tread marks are across the tread from the outward and inside, the outer wear is serious, the inner wear is lighter, and the front bundle is too large; if the wear marks are across the tread from the inside out, the inner wear is serious, the outer wear is lighter, then the front bundle is too small. (1) tire transposition and installation, in order to balance the wear and tear of full car tires, avoid abnormal wear and damage, should be timely transposed. The methods include cross transposition, cyclic transposition, mixed transposition and coaxial transposition. Among them, the cross substitution method is the most frequently used one. The advantage is that it has good adaptability to the arch road surface and can better guarantee the balanced wear of each tire. It is not necessary to remove the tread surface from the wheel when it is transposition, and the spare tire can also take part in the transposition. Cross transposition is widely used. If you have chosen this method, you should always change the location according to the selected method. When wheels are mounted on the vehicle, the tire with rotating direction will be fitted with "man" tyres and should be installed in the specified direction. When installing the rear wheel twin, two valves should be mounted opposite (180 degrees apart), and the clearance check holes between the valve and brake drum and the shoe shall be staggered. In rear wheel twin, high and low pressure tire or large and small tire can not be mixed. If the two tyres are not evenly worn, they can be worn out to suit arch road surfaces. (2) adjust steering wheel steering angle, steering wheel steering angle is too large, causing tire undulating wear. The adjustment method is to park the vehicle on the flat ground and maintain a straight line position. When turning the steering wheel, the wheel does not deflect in a certain range, indicating that the steering wheel has a large free travel, but there is no stagnation during the rotation, indicating that there is no abnormal wear and tear in the gear and rack in the steering gear. Put the car on the lifting rack, check the steering connection ball head pin and the bolt without loosening, indicating that the fault is not here. Based on the above diagnosis, the conclusion is that the steering wheel clearance is too large, resulting in too much free travel of the steering wheel. Loosen the lock nut on the steering gear, rotate the adjusting bolt with the inner six angle wrench, eliminate the meshing gap between the gear and the rack, and then lock the lock nut (notice: do not turn the adjusting bolt with the nut). In the steering system, there is no clearance between the motion pairs, that is, the steering wheel has no free travel. So once you feel that the steering wheel has a free stroke, you need to adjust and check the ball pin, ball seat and spring. If the steering gear gap is large, it may lead to a large free travel (clearance) of the steering wheel, so that there will be a large angle of rotation when steering wheel steering, and the vibration of the steering wheel will be produced, and the wave shape of the tire tread may appear. (3) the front adjustment of the front wheel toe can be ensured by adjusting the length of the tie bar. The toe in value must be adjusted according to the data provided in the instructions. When adjusting the front wheel of the wheel, the left and right wheels should be lifted in turn to lift off the ground with the jack and check the left and right swing. If the swing is too large, the clearance between two wheel hub bearings should be adjusted. If the amount is not large, the two wheels will be set up and set up, and a straight line is drawn at the center of the two tire tread, and the distance between the two lines is measured with a steel tape measure and the data are recorded. The difference between the rear data of the tire is subtracted from the front data and compared with the prescribed beam value. If the value is not consistent, the locking nut on the joint of the pull rod is loosened with the wrench, and the transverse rod is tightened or loosened. When the differential value is less than the specified value, the transverse tie bar is loosened, and the lateral tie bar is tightened when the difference value is greater than the specified value. Repeat until the adjustment is completed, and finally tighten the locking nut according to the specified torque value. (4) a relatively smooth road should be chosen to operate the vehicle reasonably, to prevent the sharp and sharp objects such as stone and glass on the road to scrape the tire or to make the tire overwear. Turn the direction in order to reduce the wear of the tire.