Note. When installing alloy wheels from other manufacturers, bolts of different sizes may be required.
Technique is improving. It may be that older models may have different tire pressures. The dimensions specified in the documents for the car are decisive.
2. With a sporty driving style, it is recommended to increase the pressure in the front and rear tires by 0.2 kgf / cm2. When increasing the pressure, the base value for the various load conditions must be taken into account.
3. Winter tires usually have pressure 0.2 kgf/cm2 higher than summer tires. The recommendations of the winter tire manufacturers must be observed.
4. Since winter tires have a speed limit, a sign indicating the maximum speed must be fixed in the driver's field of vision.
Drive designations
Example 6Jx15
- 6 - Disc width in inches
- J - Letter designation of the height and contour of the side flange of the rim of the disk
- x — Designation of one-piece deep disk
- 15 - Disc diameter in inches
- Permissible lateral runout on the side edge of the disk: 0.8 mm;
- Permissible radial runout on the disc seat: 0.5 mm.
Tire designation
Example: 195/70 R 14 89 H
- 195 - Tire width in mm
- /70 - Height to width ratio (tire cross-sectional height is 70% of the width)
Note. If there is no separate information about the ratio of width to height (e.g. 175 R 14), which means it is about «normal» relation. It is 82%.
- H - Speed class, H: up to 210 km / h (on new tires is not always given).
- R - Radial design
- 14 - Disc size in inches
- 89 - Load capacity parameter
Note. If between data 14 and 89 there is the designation M + S, we are talking about tires with a winter tread.
- H - Designation of the permissible maximum speed.
Note. The speed symbols apply to both summer and winter tyres. Letter designations of speed are given in Specifications.
Tire manufacturing date
The date of manufacture is stamped on the tire in the manufacturer's code.
Example: DOT CUL2 UM8 019 TUBELESS
- DOT — Department of Transportation (US Department of Transportation)
- CU is an abbreviation for the manufacturer's name
- L2 - tire size
- UM8 - bus version
- 4600 - date of manufacture - 46th working week of 2000
- TUBELESS - tubeless (TUBETYPE - tube tire)
- Checking the condition of your tires regularly will help you avoid the hassle of stopping on the road due to a flat tire. In addition, such checks provide valuable information about possible problems with the steering and suspension before serious damage appears in them.
- The tires are equipped with integrated tread wear indicator strips that are exposed when the tread depth drops to 1.6 mm, after which the tires are considered worn. This value represents the minimum allowable tread depth; In most cases, it is recommended to replace tires with a tread depth of 2 mm or less. Tread depth can also be determined using a simple and inexpensive device known as a tread depth gauge.
Tire wear indicators up to a depth of 1.6 mm are located in the places marked on the sidewall of the TWI
- Pay attention to any unusual wear on the treads. Tread defects such as caverns, bulges, flattening and more severe wear on one side indicate misalignment of the front wheels and/or wheel balance. If any of the listed defects are detected, you should contact the tire shop for their correction.
- Carefully check the tire for cuts, punctures, and stuck nails or buttons. Sometimes, after piercing a tire with a nail, it holds pressure for some time or deflates very slowly. If there is a suspicion that such «slow puncture» first check the tightness of the inflation valve nipple. Then inspect the tread for the presence of stuck foreign objects in it or previously sealed punctures that have begun to let air through again. If there is a suspicion that there is a puncture, you can verify its presence by wetting the suspected area with soapy water. If there is a leak, the solution will begin to bubble. If the puncture is not too big, the tire can usually be repaired at any tire shop.
- Carefully inspect the inner sidewalls of the tires for signs of brake fluid leakage. If any, check the brake system immediately.
- Maintaining the correct tire pressure increases tire life, helps save fuel and improves overall driving comfort. A pressure gauge is required to check the pressure.
Note. Keep an accurate pressure gauge in your glove box at all times - the pressure gauges built into the nozzles of the air hoses at gas stations should not be trusted.
- Always check the pressure on cold tires (those. before driving). If you check the pressure on warm or hot tires, this will lead to an overestimation of the pressure gauge due to the thermal expansion of the tires. In this case, the pressure should never be released, as after the tire cools down, it will be below normal.
- Unscrew the protective cap from the inflation valve protruding from the wheel disk or from the hub cap, then firmly press the pressure gauge nozzle onto the valve. Read the instrument readings and compare them with those recommended in the Specifications. Remember to replace the protective cap to prevent dirt and moisture from entering the nipple mechanism. Check the pressure in all four tires and, if necessary, inflate them to the recommended pressure.
- Do not forget to maintain the required pressure in the spare wheel.
Tire pressure check
Note. Air pressure should only be checked with cold tires.
The tire pressure values given for a light vehicle load are the minimum values for driving comfort. The increased air pressure in the tires, which is provided for with an increased load on the car, has a positive effect on the handling of the car even at a light load and is quite acceptable. The smoothness of rolling, however, is somewhat reduced.
1. Unscrew the valve cap.
2. Tire pressure is checked once a month, as well as during maintenance (including spare wheel). When checking, use a special pressure gauge, or a pressure gauge built into the compressor.
Note. You should not trust the readings of pressure gauges built into the nozzles of compressors used to inflate tires at gas stations.
Checking tire inflation pressure
3. In addition, the air pressure must be checked before every long trip, because. in this case, the temperature load on the tires increases.
4. The required air pressure in the tires is given on the sticker located on the inside of the fuel tank cap.
Note. When using winter tires, the air pressure must be increased by 0.2 kgf/cm2 in relation to the set value.
5. The air pressure of narrow spare tires is indicated on the sidewall of the rim. The air pressure in the tires varies depending on the change in ambient temperature by 10°C by approximately 0.1 kgf/cm2. This should be taken into account when monitoring tire pressure indoors, especially during the cold season.
Example:
- The temperature in the garage room is about + 20°С
- Outside air temperature — About 0°С
- Set tire pressure = Prescribed value, + 0.2 kgf/cm2
Checking the condition of the wheel inflation valves
Note. The valve extensions used must be checked for damage and contamination leading to leaks. Extension cords should be replaced if necessary.
1. Unscrew the protective cap and extension.
2. Apply a small amount of soapy water or saliva to the valve. If an air bubble forms, tighten the insert (3), - use the protrusion of the metal protective cap (2).
Wheel inflation valve
1, 2 - Rubber / plastic and metal protective caps
3 - Nipple
4 - valve body
3. Check the valve again. If bubbles appear and the valve cannot be tightened, it must be replaced (service station work).
4. Be sure to reinstall the protective cap.
Examples of typical tire tread wear
Lateral wear
Insufficient tire pressure causes the tire to overheat while driving due to excessive deflection, resulting in the tread not pressing sufficiently against the road surface. This results in loss of traction and excessive tread wear, not to mention the risk of tire failure due to overheating.
Check and adjust pressure.
Wrong camber (wear on one side)
Repair or replace suspension parts.
Too sharp turns
Reduce your speed!
Central wear
Overpressure
Excessive tire pressure leads to accelerated wear of the central part of the tread, reduced traction, harder driving and an increased risk of fatal damage to the tire.
Check and adjust pressure.
If you have to inflate heavy duty tires to the pressure specified for this purpose in the Specifications, be sure to bleed it after that when going into normal operation.
Uneven wear
The front tires may wear unevenly as a result of misalignment of the wheel alignment. Tire angles can be checked and adjusted for a modest fee at most tire shops.
Incorrect camber or runout
Repair or replace suspension parts.
Suspension defect
Repair or replace suspension parts.
Wheels out of balance
Perform wheel balancing.
Front wheel alignment incorrectly set
Adjust the angles of the front wheels.
Note. The frayed edges of the tread pattern, which is a sign of wear, is best detected by touch.
Wheel rotation
Note. Wheel rotation is allowed only if the size of the front and rear wheel assemblies is the same.
1. Rotate the wheels depending on the degree of tire wear every 5-10 thousand kilometers. At the same time, make sure that the direction of rotation of the wheels is maintained (for directional tires).
2. Rotation must be carried out until the characteristic signs of tire wear appear: shoulder wear (front wheels) /Mid tread (rear wheels).
3. Thoroughly clean the inside of the wheel assemblies with each rotation.
4. After completing the procedure, do not forget to check the tire inflation pressure (see above).
Attention! To avoid wheel loosening, tighten the wheel bolts strictly in accordance with the requirements of the Specifications, use only branded wheel bolts with the Mercedes-Benz logo!
Lightweight spare wheel
1. If a tire is damaged, a light-weight spare wheel is installed in place of the failed wheel assembly, which should be replaced with a standard wheel as soon as possible - the spare wheel is designed for a mileage of no more than 20,000 km.
2. If necessary, the spare wheel tire can be mounted on the impeller, provided that it matches the standard size of other impellers.
Note. Tires that have been in use for more than 6 years are recommended to be used only in extreme cases, when there is no other way out.
Models with AMG equipment
Warning! There is a danger of an accident! If a light-weight spare wheel is fitted, a change in vehicle dynamics must be taken into account due to the different tire sizes. Adapt your driving style to the situation.
1. The lightweight spare wheel is intended for short-term use only, subject to the prescribed tire pressure and a maximum speed of 80 km/h.
2. Operation with more than one lightweight spare wheel is not permitted.
Wheel replacement
See Section Jacking and towing.
Wheel bolts
1. Wheel bolts damaged mechanically or as a result of corrosion must be replaced.
2. Before screwing in, the wheel bolts should not be lubricated with any compound.
3. In case of damage to the threads in the wheel hub, immediately drive the car to a Mercedes-Benz service station for the necessary reconditioning.
4. Before installing the wheels, check the cleanliness of the mating surfaces of the discs with the hubs.
5. To avoid wheel loosening, tighten the wheel bolts strictly in accordance with the requirements of the Specifications, use only branded wheel bolts with the Mercedes-Benz logo!