The wheel bolts for steel and alloy wheels are the same size.
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.
With a sporty driving style, it is recommended to increase the pressure in the front and rear tires by 0.2 atm. When increasing the pressure, the base value for the various load conditions must be taken into account.
Winter tires usually have a pressure of 0.2 atm. higher than summer. The recommendations of the winter tire manufacturers must be observed.
Since winter tires have a speed limit, a sign indicating the maximum speed must be affixed in the driver's field of vision.
Drive designations
Example: 6 J x 15
- 6 rim width in inches
- J letter designation for the height and contour of the rim flange
- x designation of a solid deep disc
- 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). 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 wheel size in inches
- 89 load capacity parameter. 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. The speed letter is behind the tire size. 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 of the tire is on the tire in the manufacturer's code
Example: DOT CUL2 UM8 019 TUBELESS
- DOT Department of Transportation (US Department of Transportation)
- CU manufacturer's abbreviation
- 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.
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 the tire with a nail, it holds pressure for some time or lowers 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 any stuck foreign objects or previously repaired punctures that are re-breathing. 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.
Recommendations: Always keep an accurate pressure gauge in your glove box. Pressure gauges built into the nozzles of air hoses at service stations are often inaccurate.
Always check the pressure on cold tires (those. before driving). If you check the pressure on warm or warm tires, this will lead to an overestimation of the pressure gauge due to 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 readings of the device and compare them with those recommended in 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
Air pressure should only be checked with cold tires.
1. Unscrew the valve cap.
2. Tire pressure is checked once a month, as well as during maintenance (including spare wheel).
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 atm. 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 atm. This should be taken into account when checking the tire pressure in the garage - especially in winter.
Example: The temperature in the garage is around +20°C. The outside air temperature is about 0°C. Installed air pressure in tires = specified air pressure +0.2 atm.
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.
Tire valve
1 and 2 - rubber and metal caps
3 - valve
4 - valve body
Tire valve check
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 valve 3 with protective cap 2.
Note. To tighten the valve, use only the protective cap 2. 1 rubber protective cap, 4 valve.
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.
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
Wheel rotation is only permitted if the front and rear wheels are the same size.
Rotate the wheels depending on tire wear every 5000-10000 km. At the same time, keep the direction of rotation of the wheels.
Rotation must be done before the characteristic signs of tire wear appear. A characteristic sign of wear for front wheel tires is the wear of the shoulder area of the tread, and for rear wheel tires - the middle of the tread.
With each rotation of the wheels, it is necessary to thoroughly clean them from the inside. After rotating the wheels, check and, if necessary, correct the air pressure in the tires (see above).
The wheel bolts can loosen if they are not tightened to the torque specified in the Specifications. After changing the wheels, check the tightening torque.
Use only branded mounting bolts «MB», marked with a star «Mercedes-Benz». Other bolts may loosen.
Lightweight spare wheel
If a tire is damaged, the lightweight spare wheel can be used as a normal wheel; it is recommended, however, to replace it with a normal wheel as soon as possible, as it is designed for a limited mileage of up to a maximum of 20,000 km.
When changing tires, the spare wheel tire can be mounted on the impeller if the tire matches the design of the impeller tyres. If the tire is older than 6 years, it is recommended to use it only if the tire is damaged.
Models with 245/45R18 tires
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 traffic situation.
Replace the lightweight spare wheel with a regular wheel as soon as possible.
Models with AMG equipment
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.
It is therefore intended only for short-term use, subject to the prescribed tire pressure and a maximum speed of 80 km/h.
Operation with more than one lightweight spare wheel is not permitted.
Wheel replacement
One of the wheel bolts
1 - Used for light discs
2 - Used for steel rims
The car jack is intended only for briefly lifting the car when changing a wheel.
The base of the car jack must be firm and level. In case of loose ground, use a car jack pad.
For work under the car, it is necessary to use dummy goats.
1. Put the car, if possible, on a flat area. Firmly press the parking brake pedal. The parking brake must not be released while the vehicle is raised.
2. Move the AT selector lever to position «R». Protect the vehicle from rolling away by placing wheel chocks, etc.
3. On level ground: Chock the diagonal wheel front and rear.
4. On uphills and downhills: place chocks under both wheels of the other axle in the downhill direction.
5. Remove the wheel wrench from the vehicle tool kit.
6. Loosen the wheel bolts with a wrench, but do not completely remove them yet.
7. Push the jack fully into the jack hole. The car jack must always be upright – also on slopes.
8. Raise the car until the wheel is off the ground.
9. To prevent the vehicle from slipping, the support pin of the jack is completely (all the way) insert into the jack hole on the vehicle.
10. Turn out the top bolt of fastening. Screw the centering pin -1- from the on-board tool kit into the threaded hole. Remove the remaining wheel bolts. Do not place wheel bolts on sand or mud.
11. Remove the wheel.
Wheel bolts
1. Replace wheel bolts that are damaged or rusty.
2. Do not lubricate the bolts with oil or grease.
If the thread in the wheel hub is damaged, you cannot continue driving. Need to go to service station «Mercedes-Benz».
3. Clean the contact surface of the wheel and hub.
Use only branded mounting bolts «MB», marked with a three-pointed star «Mercedes-Benz». Other bolts may loosen.
4. Fit and press the wheel.
5. Screw in the wheel bolts and tighten slightly.
6. Unscrew the centering pin and screw in the last wheel bolt.
7. Lower the car. Remove the car jack.
8. Tighten all wheel bolts evenly. The tightening scheme is shown in the illustration. The tightening torque is specified in Specifications.
There is a danger of an accident!
The wheel bolts can loosen if they are not tightened to the correct torque. Therefore, be sure to check the tightening torque immediately after changing the wheels.
Attention!
- Before laying the car jack in the additional compartment under the boot floor, turn the jack support pin back almost to the stop.
- Disassemble the wheel wrench and place it in the vehicle tool kit.
- Check and, if necessary, correct the air pressure in the tires.
Checking the expiration date of the sealant «TIREFIT» for tires
Depending on the equipment, the vehicle may have a bottle of tire sealant instead of a spare wheel «TIREFIT».
1. Open the tailgate and boot floor.
2. Take out the bottle of TIREFIT (1) and check the expiration date on the label (2). Suitability is maintained for 3 years from the date of manufacture. At the end of the specified period, replace the sealant. The date of manufacture and expiry date are printed on the TIREFIT label.
3. If necessary, when buying a new sealant, the old one can be recycled.
4. Close the boot floor and tailgate.