BMW M3 Owner's Manual page 171

Mobility
Tire size
All pressure specifications in the table are
indicated in bar/psi with cold tires.
Cold = ambient temperature
Front: 225/35 R 19 88 Y XL
Rear: 255/30 R 19 91 Y XL
Compact spare wheel:
T 125/80 R 17 99 M
170
Wheels and tires
Online Edition for Part no. 01402918638 - © 02/13 BMW AG
Pressure specifications in bar/psi
Traveling speeds up
to a max. of
100 mph/160 km/h
2.5/36 -
- 3.0/44
Traveling speeds up to a max. of 50 mph/80 km/h
Traveling speeds
including those
exceeding
100 mph/160 km/h
2.7/39
- 3.2/46
4.2/60
-