Notes on MO Extended tires - AH40.10-P-0010-01A
Model 164, 169, 171, 203, 204, 209, 211, 215, 216, 219, 220, 221, 230, 245, 251
Design
MO Extended stands for Mercedes Original Extended tires These tires have a strengthened side wall which supports the weight resting on the wheel if pressure loss occurs and enables the vehicle to drive on to a limited extent. The SA MO Extended is permanently coupled to a tire pressure monitoring system. This can be a tire pressure loss warning (RDW) indirect measurement system or a tire pressure monitor (TPM) direct measurement system. Use of MO Extended tires without air pressure monitoring is not permissible as through the stable sidewall a pressure loss can only be detected with difficulty or not at all.
- On vehicles with a tire pressure monitoring (RDK) system which measures directly a sensor must be installed on each wheel.
- Commercially available valves without sensors must be fitted to vehicles with the tire pressure loss warning (RDW) indirect measuring system.
- Wheels of older model series are not designed and safeguarded for the higher MO Extended loading. Therefore MO Extended tires may only be fitted on the model series on which according to the overview for disk wheels an MO Extended tire is also offered.
- MO Extended tires should only be fitted on Mercedes-Benz wheels in order to avoid a reduction in component service life.
- It is not permissible to repair damaged MOExtended tires.
Advantage
The use of MO Extended tires offers the following significant advantage:
- Extended mobility i.e. in the event of tire damage there is the possibility of exiting critical areas such as highways or tunnels.
Emergency running distance
The emergency running distance depends of the road condition, the driving style as well as the loading condition of the vehicle and is:
- Approx. 30 km when vehicle is fully loaded.
- approx. 50 km in the partially laden condition.
It starts with the appearance of the pressure loss warning message in the multifunction display.
By using TIREFIT the emergency running distance can be significantly increased in the event of minor damage.
If an air loss occurs in one or more tires the driving characteristics should be adapted accordingly. The maximum permissible speed of 80 km/h must not be exceeded otherwise the emergency running characteristics are no longer valid.
If a tire has been driven with low air pressure, the wheels, valves and wheel sensors in question are to be checked for damage in order to safeguard the function of the system.
Method of functioning of tire pressure monitor (Beru), shown on model 219
The driver adjusts the required tire pressure in all wheels. After this the tire pressure is stored in the TPM control unit via the button + and a, adjustment of specific functions and volume control (S111s1) on the multifunction steering wheel (N88).
While driving, the system now compares the existing tire pressure in each wheel with the stored values every 3 or 4 seconds. If a difference is measured, the driver is informed immediately via the multifunction display (A1p13) in the instrument cluster (A1).
Functionality of tire pressure loss warning system, shown on model 219
The tire pressure loss warning (RDW) itself takes place without the position of the affected tire being given and is only active from a speed of 15 km/h. When the vehicle is driven normally, the Electronic Stability Program or Sensotronic Brake Control system performs very precise evaluation of the wheel speeds provided by the rpm sensors (L6/1 to L6/4). If a speed difference is now measured, this means that a tire has a pressure loss. The error message is lead directly to the instrument cluster (A1) and is displayed to the driver in the form of an information message in the multifunction display (A1p13).
For each check or adaptation of tire pressure as well as for each wheel or tire change the tire pressure loss warning (RDW) system must be restarted (see operator's manual).