3.6. Check of a condition of tires and pressure in them. Designation of tires and disks of wheels. Rotation and replacement of wheels
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Designations of disks
Example: 6 J x 15
6 width of a disk in inches
J alphabetic reference of height and contour of an onboard zakraina of a rim of a disk
x designation of an integral deep disk
15 diameter of a disk in inches
Admissible side beating on the onboard zakrayena of a disk: 0.8 mm;
Admissible radial beating on the landing shelf of a disk: 0.5 mm.
Designation of tires
Example: 195/70 R 14 89 H
195 width of the tire in mm
/70 height relation to width (height of cross section of the tire makes 70% of width)
If hotel data on width relation to height are absent (for example, 175 R 14), means it is about the "normal" relation. It makes 82%.
N class of speed, N: to 210 km/h (on new tires it is brought not always).
R radial design
14 size of a disk in inches
89 parameter of loading capacity
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If between data 14 and 89 there is a designation M+S, it is about tires with a winter protector. |
N designation of admissible maximum speed.
The letter of speed stands behind the tire size. Symbols of speed belong both to summer, and to winter tires.
Alphabetic references of speed are given in Specifications.
Date of production of the tire
Date of production of the tire is installed on the tire in a code of the producer
Example: DOT CUL2 of UM8 4600 TUBELESS
DOT Department of Transportation (U.S. Department of Transportation)
CU reduction of the name of the manufacturer
L2 tire size
UM8 execution of the tire
4600 date of production - the 46th working week 2000
TUBELESS tubeless (TUBETYPE - the tire with the camera)
Regular check of a condition of tires will allow you to avoid the troubles connected with stops in way because of the lowered wheel. Besides, such checks give valuable information on possible problems with steering and a suspension bracket before emergence in them serious damages.
Pay attention to any unusual wear of protectors. Such defects of a protector as cavities, cambers, flattening and stronger wear on the one hand indicate violation of angles of installation of forward wheels and/or balancing of a wheel. At identification any of the listed defects it is necessary to address for their adjustment in a tire workshop.
Carefully check the tire for existence of cuts, punctures and the got stuck nails or buttons. Sometimes after piercing of the tire a nail it still some time holds pressure or lowers very slowly.
At suspicion at first check tightness of the nipple of the gate of a rating for existence of such "slow puncture". Then examine a protector on presence at it of the got stuck foreign objects or punctures which are closed up earlier which started over again passing air. If there is a suspicion that there is a puncture, it is possible to make sure of its existence, having moistened the suspected site with soap water. In the presence of leak solution will begin to bubble. If a puncture not too big, the tire it is usually possible to repair in any tire workshop.
Carefully examine the internal side surfaces of tires on existence of signs of leak of brake fluid on them. If those are available, immediately check the brake system.
Maintenance in tires of the correct pressure increases the term of their service, helps to save fuel and improves the general comfort of the movement. The special manometer is necessary for check of pressure.
Recommendations: Always you keep the exact manometer in the ware box. Indications of the manometers which are built in nozzles of air hoses at stations of service often happen inexact.
Always check pressure on cold tires (i.e. to a trip on the car). If to check pressure on the warm or warmed tires, it will lead to overestimate of indications of the manometer because of thermal expansion of tires. In this case it is never necessary to lower pressure since after cooling of the tire it will appear below norm.
Screw together a protective cap from the gate of a rating acting from a disk of a wheel or from a nave cap then densely press a manometer nozzle to the gate. Consider instrument readings and compare them with recommended in Specifications. Do not forget to install into place a protective cap for prevention of hit in the mechanism of the nipple of dirt and moisture. Check pressure in all four tires and if necessary pump up them to the recommended value of pressure.
Do not forget to support the required pressure and in a spare wheel.
Check of pressure of air in tires
An inspection of pressure of air should be carried out only on cold tires.
Check of the gate of tires
Gate of tires|
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1 and 2 — Rubber and metal caps |
4 — the gate Case |
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Examples of characteristic wear of protectors of tires
Side wear
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Insufficient pressure in the tire leads to its overheat at the movement owing to an excessive deflection therefore the protector does not nestle sufficiently on the surface of the road. It leads to loss of coupling with the road and to excessive wear of a protector, not to mention danger of an exit of the tire out of operation as a result of an overheat.
Check and adjust pressure.
Wrong disorder of wheels (wear on the one hand)
Repair or replace suspension bracket details.
Too sharp turns
Reduce speed!
Central wear
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Excessive pressure
Excessive pressure in the tire results in the accelerated wear of the central part of a protector, decrease in coupling with the road, more rigid movement and increase of danger of fatal damage of a slope.
Check and adjust pressure.
If you had to pump up tires for transportation of heavy freights to the value of pressure specified for this purpose in Specifications, do not forget to pit after that it upon transition to the normal mode of operation.
Uneven wear
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Tires of forward wheels can unevenly wear out as a result of violation of adjustment of angles of installation of wheels. It is possible to check and adjust the angles of installation for a moderate payment in the majority of tire workshops.
Wrong disorder or выбег
Repair or replace suspension bracket details.
Defect of a suspension bracket
Repair or replace suspension bracket details.
Wheels are debalanced
Make balancing of wheels.
Convergence of forward wheels is incorrectly established
Adjust the angles of installation of forward wheels.
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The Obtrepannost of edges of a pattern of a protector which is a wear sign best of all comes to light to the touch. |
Rotation of wheels
Rotation of wheels is allowed only at the identical size of forward and back wheels.
Rotation of wheels you produce each 5000-10000 km depending on wear of tires. At the same time keep the direction of rotation of wheels.
Rotation needs to be made before emergence of characteristic signs of wear of tires. A characteristic sign of wear at tires of forward wheels is wear of a humeral zone of a protector, and at tires of back wheels — the middle of a protector.
At each rotation of wheels it is necessary to clear carefully them from the inside. After rotation of wheels check and if necessary modify air pressure in tires (see above).
Bolts of fastening of wheels can weaken if they were not brought up with the inhaling moment specified in Specifications. After replacement of wheels check the inhaling moment.
Apply only company bolts of fastening of "MB" designated by a star of "Mercedes-Benz". Other bolts can unscrew.
Spare wheel of the facilitated design
At damage of the tire the spare wheel of the facilitated design can be used as a normal wheel; it is recommended to replace, however, as soon as possible it with a normal wheel as it is calculated on a limited run as much as possible to 20 000 km.
When replacing tires the tire of a spare wheel can be mounted on the driving wheel if the tire corresponds to execution of tires of driving wheels. If the tire is more senior than 6 years, it is recommended to be applied only at damage of the tire.
Models with tires 245/45R18:
If the spare wheel of the facilitated design is mounted, then owing to various sizes of tires it is necessary to reckon with change dynamic property of the car. Conform style of driving with a road situation.
As soon as possible replace a spare wheel of the facilitated design with a usual wheel.
Models with a complete set of AMG
There is a danger of accident!
If the spare wheel of the facilitated design is mounted, then owing to various sizes of tires it is necessary to reckon with change of dynamic properties of the car. Conform style of driving to this situation.
It therefore, it is provided only for short-term use at observance of the ordered air pressure in tires and the maximum speed of 80 km/h.
Operation with more, than one spare wheel of the facilitated design is inadmissible.
Replacement of wheels
The automobile jack is intended only for short-term raising of the car when replacing a wheel.
The basic platform of an automobile jack has to be firm and equal. In case of friable soil use a lining for an automobile jack.
Under the car it is necessary to apply a false trestle to work.
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Bolts of fastening of wheels
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