BMW X3 Service & Repair Manual: Notes on exchanging tires during repair

General:

• The tire size, manufacturer and tire tread must be the same on one axle
• To meet the BMW standards, the vehicle should be equipped with tires from the same manufacturer and with the same tire tread (tires approved by BMW) on all 4 wheels
• The difference in tire tread depth on one axle must not exceed 2 mm (control quality of suspension control systems and wheel alignment requirement)
• The tires with the higher tread depths must be mounted on the rear axle
• The DOT age difference must not exceed 4 years
• On exchanging the tires, the tire pressure must be adjusted

Additionally for all-wheel drive vehicles:

• The tire size, manufacturer and tire tread must be identical on all wheels; if mixed tires are fitted, different dimensions are permissible.
• The difference in tire tread depth on all wheels must not exceed 2 mm (control quality of suspension control systems and wheel alignment requirement)