Tires - Mounting On AH or AH2 Wheels
90bmw02Group 36 Tires and Wheels
Bulletin Number 36 01 90 (3026) Page 1 of 2
Woodcliff Lake, NJ February 1990 Service Engineering
SUBJECT: Mounting of Tires on AH or AH2 Wheels
MODELS: M5 (E34)
Situation: The M5 has 8J x 17AH (or AH2) wheels, which require slightly revised mounting and dismounting procedures. This is due to the asymmetric hump of the rim profile, which requires that dismounting the tire be started in the area of the valve, where the profile of the hump is smaller.
The instructions provided on the attachment should be made available to those personnel that change fires. These instructions will be included in an upcoming version of the Repair Manual.
Removing and Installing Tires on Asymmetric Hump Rims
Indentifying Asymmetric Hump Rims
The designation AH or AH2 will appear following the rim diameter where the wheel size is cast into the wheel, e.g., 8J x 17AH (or AH2).
Features of Asymmetric Hump Rims
The profile of the hump in the bead seating area changes around the rim. This can make breaking the bead on a tire machine extremety difficuft.
Removing Tire from AH Rim
Breaking the bead must begin in the area of the valve, for both inner and outer beads. This allows the bead to release more easily. The fire may then be removed in the normal manner.
Mounting Tire on AH Rim
The tire is mounted in the normal manner, but close aftention should be paid to seating of the bead. If the bead does not seat at 3.5 Bar (50 PSI), the air should be released and the rim liberally coated again with tire fitting lubricant.