Wheels and tires
Tire inflation pressure
Safety information
The tire characteristics and tire inflation pressure influence the following:
The service life of the tires.
Road safety.
Driving comfort.
Checking the pressure
Tires have a natural, consistent loss of pressure.
Tires heat up during driving, and the tire inflation pressure increases along with the temperature of the tire. The tire inflation pressure specifications relate to cold tires or tires with the ambient temperature.
Only check the tire inflation pressure when the tires are cold. This means after driving no more than 1.25 miles/2 km or when the vehicle has been parked for at least 2 hours.
The displays of inflation devices may under-read by up to 0.1bar, 2 psi .
For Tire Pressure Monitor: after correcting the tire inflation pressure, reset the Tire Pressure Monitor.
Pressure specifications
The tire inflation pressure table contains all pressure specifications for the specified tire sizes at the ambient temperature. The tire inflation pressure values can be found in the printed Owner's Manual and they apply to approved tire sizes and recommended tire brands. This information can be obtained from your service center.
To identify the correct tire inflation pressure, please note the following:
Tire sizes of your vehicle.
Maximum permitted driving speed.
Tire inflation pressures up to 100 mph/160 km/h
For speeds of up to 100 mph/160 km/h and for optimum driving comfort, note the tire inflation pressure values in the printed Owner's Manual and adjust as necessary.

These pressure values can also be found on the tire inflation pressure label on the driver's door pillar.
Tire inflation pressures at max. speeds above 100 mph/160 km/h
Tire inflation pressure values
The tire inflation pressure values can be found in the printed Owner's Manual.
Tire identification marks
Tire size
245/45 R 18 96 Y
245: nominal width in mm
45: aspect ratio in %
R: radial tire code
18: rim diameter in inches
96: load rating, not for ZR tires
Y: speed rating, before the R on ZR tires
Speed letter
Q = up to 100 mph, 160 km/h
R = up to 106 mph, 170 km/h
S = up to 112 mph, 180 km/h
T = up to 118 mph, 190 km/h
H = up to 131 mph, 210 km/h
V = up to 150 mph, 240 km/h
W = up to 167 mph, 270 km/h
Y = up to 186 mph, 300 km/h
Tire Identification Number
DOT code: DOT xxxx xxx 0814
xxxx: manufacturer code for the tire brand
xxx: tire size and tire design
0814: tire age
Tires with DOT codes meet the guidelines of the U.S. Department of Transportation.
Tire age
DOT … 0814: the tire was manufactured in the 8th week of 2014.
Recommendation
Regardless of wear, replace tires at least every 6 years.
Uniform Tire Quality Grading
Quality grades can be found where applicable on the tire sidewall between tread shoulder and maximum section width.
For example: Treadwear 200; Traction AA; Temperature A
DOT Quality Grades
Treadwear
Traction AA A B C
Temperature A B C
All passenger car tires must conform to Federal Safety Requirements in addition to these grades.
Treadwear
The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one and one-half, 1 g, times as well on the government course as a tire graded 100. The relative performance of tires depends upon the actual conditions of their use, however, and may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate.
Traction
The traction grades, from highest to lowest, are AA, A, B, and C.
Those grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance.
The traction grade assigned to this tire is based on straight-ahead braking traction tests, and does not include acceleration, cornering, hydroplaning, or peak traction characteristics.
Temperature
The temperature grades are A, the highest, B, and C, representing the tire's resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and excessive temperature can lead to sudden tire failure. The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Vehicle Safety Standard No. 109. Grades Band A represent higher levels of performance on the laboratory test wheel than the minimum required by law.
M+S
Winter and all-season tires with better cold weather performance than summer tires.
Tire tread
Summer tires
Do not drive with a tire tread depth of less than 0.12 in/3 mm .
There is an increased danger of hydroplaning if the tread depth is less than 0.12 in/3 mm .
Winter tires
Do not drive with a tire tread depth of less than 0.16 in/4 mm .
Below a tread depth of 0.16 in/4 mm , tires are less suitable for winter operation.
Minimum tread depth

Wear indicators are distributed around the tire's circumference and have the legally required minimum height of 0.063 in/1.6 mm .
They are marked on the side of the tire with TWI, Tread Wear Indicator.
Tire damage
General information
Inspect your tires often for damage, foreign objects lodged in the tread, and tread wear.
Notes
Driving over rough or damaged road surfaces, as well as debris, curbs and other obstacles can cause serious damage to wheels, tires and suspension parts. This is more likely to occur with low-profile tires, which provide less cushioning between the wheel and the road. Be careful to avoid road hazards and reduce your speed, especially if your vehicle is equipped with low-profile tires.
Indications of tire damage or other vehicle defects:
Unusual vibrations during driving.
Unusual handling such as a strong tendency to pull to the left or right.
Damage can, e. g., be caused by driving over curbs, road damage, or similar things.
Changing wheels and tires
Mounting
Wheel and tire combination
You can ask the service center about the right wheel/tire combination and wheel rim versions for the vehicle.
Incorrect wheel and tire combinations impair the function of a variety of systems such as ABS or DSC.
To maintain good handling and vehicle response, use only tires with a single tread configuration from a single manufacturer.
Following tire damage, have the original wheel and tire combination remounted on the vehicle as soon as possible.
Recommended tire brands

For each tire size, the manufacturer of your vehicle recommends certain tire brands. These can be identified by a star on the tire sidewall.
With proper use, these tires meet the highest standards for safety and handling.
New tires
Due to technical factors associated with their manufacture, tires do not achieve their full traction potential until after an initial breaking-in period.
Drive conservatively for the first 200 miles/300 km .
Retreaded tires
The manufacturer of your vehicle does not recommend the use of retreaded tires.
Winter tires
Winter tires are recommended for operating on winter roads.
Although so-called all-season M+S tires do provide better winter traction than summer tires, they do not provide the same level of performance as winter tires.
Maximum speed of winter tires
If the maximum speed of the vehicle is higher than the permissible speed for the winter tires, then display a corresponding sign in the field of vision. You can obtain this sign from the tire specialist or from your service center.
Rotating wheels between axles
Rotating the tires is not permissible on vehicles with different tire sizes on the front and rear axles, i.e. when using different types of tires.
Storage
Store wheels and tires in a cool, dry place with as little exposure to light as possible.
Always protect tires against all contact with oil, grease and fuels.
Do not exceed the maximum tire inflation pressure indicated on the side wall of the tire.
Snow chains
Fine-link snow chains
Only certain types of fine-link snow chains have been tested by the manufacturer of the vehicle, classified as road-safe and approved.
Information about the approved snow chains are available from the service center.
Use
Use only in pairs on the rear wheels, equipped with the tires of the following size:
255/40 R 18
255/35 R 19
Follow the chain manufacturer's instructions.
Make sure that the snow chains are always sufficiently tight. Retighten as needed according to the chain manufacturer's instructions.
Do not initialize the Tire Pressure Monitor after mounting snow chains, as doing so may result in incorrect readings.
When driving with snow chains, if necessary briefly activate M Dynamic Mode.
Maximum speed with snow chains
Do not exceed a speed of 30 mph/50 km/h when using snow chains.