Brakes - Brake Rotor Minimum Thickness Information

SI M34 01 10
Brakes

June 2011
Technical Service

SUBJECT
Brake Rotor Minimum Thickness

MODEL
All

INFORMATION

MINI brake discs/rotors are stamped with a Minimum Thickness. The stamped minimum thickness is used to determine whether the brake discs/rotors require replacement during a brake service, such as a pad replacement. However, some motor vehicle inspection procedures require the measurement of brake discs/rotors. An additional minimum thickness specification for the purpose of motor vehicle inspection is provided in the Technical Data section of the Repair Manual. Examples of the two specifications are described in this bulletin.

The Stamped Minimum Thickness (MIN TH) is utilized as described below:

New brake pads may only be installed if the brake disc thickness is greater than or equal to the minimum brake disc thickness (MIN TH) (not including perforated brake discs).

For vehicles fitted with perforated (cross-drilled) brake discs, new brake pads may only be installed if the brake disc thickness is greater than the stamped minimum thickness (MIN TH).

The Minimum Thickness for general inspection (Motor Vehicle Inspection) is defined as follows:

Nominal size thickness minus 2.4 mm (not including perforated brake discs)

For vehicles fitted with perforated (cross-drilled) brake discs: nominal size thickness minus 1.6 mm

Note:
Nominal size thickness refers to the width of a new rotor.

Always refer to the Repair Manual for model-specific information.