See also:

Tire identification marks
Tire size 255/50 R 19 103 Y 255: nominal width in mm 50: aspect ratio in % R: radial tire code 19: rim diameter in inches 103: load rating, not for ZR tires Y: speed rating, before the R on ZR ...

Owner's Manual for Vehicle
Thank you for choosing a BMW. The more familiar you are with your vehicle, the better control you will have on the road. We therefore strongly suggest: Read this Owner's Manual before starting off ...

Tire inflation pressure values up to100 mph/160 km/h
X3 28i X3 35i ...