Note. Non-Mercedes-Benz alloy wheels may require different bolt sizes.
Note. If there is any discrepancy between the tire inflation pressures given in Specifications and on the nameplate fixed on the inside of the fuel tank filler cap, the latter should be considered decisive.
With a sporty driving style, it is recommended to increase the pressure in the front and rear tires by approximately 0.2 kgf/cm2, based on the basic values for different load conditions.
Winter tires usually have inflation pressures 0.2 kgf/cm2 higher than summer tires - pay attention to winter tire manufacturers' recommendations.
Do not forget that the use of winter tires usually imposes restrictions on high-speed driving modes.
Drive designations
Example 7S J x 16 H2 ET63
- 7Ѕ — Disc width in inches
- J - Letter designation of the height and contour of the side flange of the disc rim
- x - Designation of a solid deep disk
- 16 — 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: 205/70 R 16 112 H
- 195 — Tire width in mm
- /70 - Height to width ratio (tire cross-sectional height is 70% of the width)
If there is no separate information about the ratio of width to height (e.g. 205 R 16), which means it is about «normal» ratio of 82%.
- R - Radial design
- 16 — Disc size in inches
- 112 — Load capacity parameter
- H — Designation of the permissible maximum speed
The speed symbols apply to both summer and winter tyres. Letter designations of speed are given in Specifications.
Note. The additional designation M + S indicates that the tire tread has a winter design.
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 - abbreviation of the manufacturer's name
- L2 - tire size
- UM8 - tire design
- 4600 - date of manufacture - 46th working week of 2000
- TUBELESS - tubeless (TUBETYPE - tire with a camera)
Regularly checking the condition of the tires helps to avoid the hassle associated with stopovers due to a flat tire. In addition, such checks provide valuable information about possible steering and suspension problems long before more serious symptoms occur.
Tread depth
Tire tread wear indicators up to a depth of 1.6 mm are located in the places marked on the sidewall with the letters TWI
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.
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 side surfaces of the tires for signs of brake fluid leakage - if any, immediately check the condition of the relevant brake mechanisms.
Tire pressure check
Attention! Checking the air pressure should only be carried out on cold tyres!
Note. Tire pressures given for a light vehicle load are the minimum values for driving comfort. Increasing the tire inflation pressure in accordance with the recommendations with an increase in the degree of loading has a positive effect on the controllability of the car and is also allowed for use under normal loading, although it is associated with some violation of the smoothness of the ride.
1. 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.
2. 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.
3. 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 readings of the device and compare them with those recommended in Specifications / on a label affixed to the back of the fuel filler cap. 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.
4. Do not forget to maintain the required pressure in the spare tire.
5. Unscrew the valve cap.
6. 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.
7. In addition, the air pressure must be checked before every long trip, because. in this case, the temperature load on the tires increases.
8. 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.
9. 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:
- Temperature in the garage room: about + 20°С
- Outside temperature: about 0°C
- Adjustable 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 leakage. Extension cords should be replaced if necessary.
Wheel inflation valve
1 and 2 - Rubber / plastic and metal protective caps
3 - nipple
4 - valve body
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 nipple using the tab on the metal protective cap.
3. Check the valve again. If bubbles appear and the valve cannot be tightened, it should be replaced - drive the car to a tire shop.
4. Don't forget to screw the protective cap back on.
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 the pressure;
- Wrong camber (wear on one side) - repair or replace suspension parts;
- Too sharp turns - slow down!
Central wear
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 had to inflate tires for transporting heavy loads to the specified for this purpose in Specifications pressure values, do not forget to bleed it afterwards when returning to 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! Tighten the wheel bolts properly to prevent loosening of the wheels Specifications, use only genuine Mercedes-Benz wheel bolts!
Lightweight spare wheel
On AMG equipment models, in the event of tire damage, a light-weight spare wheel is installed in place of the failed wheel assembly, which should be replaced with a standard one as soon as possible - a compact spare wheel is designed for a mileage of no more than 20,000 km. The speed of movement with the compact spare tire installed should not exceed 80 km/h.
The use of more than one lightweight spare wheel at the same time is not permitted.
Wheel replacement
See Section Jacking/hanging the car and transportation in case of an accident.
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. Tighten the wheel bolts properly to prevent loosening of the wheels Specifications, use only genuine Mercedes-Benz wheel bolts!