3.6. Check of a condition of tires and pressure in them. Designation of tires and disks of wheels. Rotation and replacement of wheelsDepending on model and equipment tires and disks of various sizes can be installed. Disks have depth of a press fitting of 38 mm. Depth of a press fitting is a distance from the middle of a disk to a persistent surface of a wheel on a brake disk or a drum. Wheel bolts for steel and light-alloy wheels have the identical sizes.
At installation of light-alloy wheels of other producers bolts of other sizes can be required.
The equipment is continuously improved. It is possible that for older models other values of pressure in tires are admissible. The sizes specified in documents to the car are defining.
At a sports manner of driving it is recommended to increase pressure in forward and back tires by 0.2 atm. At increase in pressure it is necessary to proceed from a base-line value for various conditions of loading.
Winter tires as a rule have pressure upon 0.2 atm. above than summer. It is necessary to consider recommendations of manufacturers of winter tires.
As winter tires have restriction on speed, in sight of the driver the plate with the indication of the maximum speed has to be strengthened.
Designations of disks
Example: 6 J x 15
6 — disk width in inches
J — alphabetic reference of height and a 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 — tire width in mm
/70 — height relation to width (height of cross section of the tire makes 70% of width)
If separate data on width relation to height are absent (for example, 175 R 14), means it is about the "normal" relation. It makes 82%.
N — a class of speed, N: to 210 km/h (on new tires it is brought not always).
R — a radial design
14 — the disk size in inches
89 — loading capacity parameter
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 as 6.6 Indicators of wear of a protector of the tire up to the depth of 1.6 mm are in the places designated on TWIK sidewall 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
DOT CUL2 of UM8 019 TUBELESS
DOT — Department of Transportation (U.S. Department of Transportation)
CU — reduction of the name of the manufacturer
L2 — the 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 existence of the got stuck foreign objects or punctures repaired earlier which are 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.
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.
Turn off a gate cap.
Air pressure in tires is checked once a month, and also when carrying out service (including spare a wheel).
Besides, pressure of air need to be checked before each long trip since in this case temperature load of tires increases.
Necessary pressure of air in tires is given in the sticker which is on inside of a cover of the fuel tank.
At use of winter tires pressure of air has to be increased by 0.2 atm. in relation to the established value.
Pressure of air of narrow tires of a spare wheel is specified on a disk sidewall.
Air pressure in tires changes depending on change of temperature of air on 10 °C approximately on 0.1 atm. It should be considered at monitoring procedure of pressure of air in tires in a garage — especially in the winter.
Temperature in a garage about + 20 °C
Temperature of external air is about 0 °C
The established air pressure in tires = the specified air pressure + 0.2 atm.
The values of pressure of air in tires given for small loading of the car are the minimum values providing comfortableness of the movement.
The elevated pressure of air in tires provided at the raised car loading positively affects controllability of the car as well at small loading and is quite admissible. Smoothness of swing at the same time, however, decreases a little.
Check of the gate of tires
The used extenders of gates have to be checked for existence of the damages and pollution leading to leakage. If necessary extenders should be replaced.
Gate of tires
Examples of characteristic wear of protectors of tires
Wrong disorder of wheels (wear on the one hand)
Repair or replace suspension bracket details.
Too sharp turns
Excessive pressureExcessive 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.
Tires of forward wheels can unevenly wear out as a result of violation of adjustment of angles of installation of wheels.
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.
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.
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.
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.
Bolts of fastening of wheels
There is a danger of accident! Bolts of fastening of wheels can weaken if they were not brought up with the required moment. Therefore surely check the inhaling moment right after replacement of wheels.
Before laying of an automobile jack in an additional compartment under a trunk floor turn a basic finger of a jack back almost to a support.
Check and, if necessary, modify air pressure in tires.