Along with the width of the rim, the depth of its pressing is also important. The pressing depth is the distance from the middle of the rim to the contact surface of the wheel disk to the brake disk.
All disk wheels are made in the form of so-called deep hump rims. The hump is a protrusion pressed onto the rim shelf, which, even during extremely sharp turns of the car, does not allow the tubeless tire to come off the rim.
If tires or rims are installed that are not indicated in the vehicle documents, an appropriate entry must be made in the documents. As a rule, permission from BMW is required for this.
Wheel and tire sizes, tire inflation pressure
All overpressure data refer to cold tires (at ambient temperature). Higher overpressure established during long journeys (by about 0.2-0.4 bar) no need to downgrade.
Since tires with winter tread patterns have a maximum speed limit, the speed limit must be observed in the driver's field of vision (§ 36 para. 1 of the StVZO technical requirements for the operation of road transport).
Attention: Technical progress does not stand still. It may also be possible for older vehicles to use different tire inflation pressures or other combinations with rims. Therefore, it is recommended to obtain up-to-date information on the admission of wheels for operation at a service station for BMW cars.
For sporty driving, it is recommended to increase the excess pressure in the tires of the front and rear wheels by 0.2 bar. When increasing, it is necessary to proceed from the base value of excess pressure, normalized for different loads.
If there is a trailer, increase the tire inflation pressure to the value indicated in the column "Full load". The spare tire inflation pressure corresponds to the maximum inflation pressure of the rear tires.
When inflating tires, refer to the label on the door pillar on the driver's side.
Attention: Road traffic regulations permit the operation of tires until the depth of the tread pattern profile over the entire working surface reaches a value of 1.6 mm. However, for safety reasons, it is recommended to replace summer tires with new ones with a profile depth of 2 mm, and winter tires with a profile depth of 4 mm. The vehicle may be equipped with a tire pressure monitoring system (RDS). The system monitors tire pressure both while stationary and while driving, taking vehicle speed and ambient temperature into account. To do this, a transmitter with temperature and pressure sensors is installed on each wheel, including the spare one, which is powered by a lithium battery designed for 5 years. The transmitter transmits signals to a receiving antenna located in the wheel arch and connected to the central control unit. Thanks to RDS, it is possible to avoid tire damage, which is dangerous especially during a trip, which occurs due to excessive sidewall collapse at too low an inflation pressure.