Wheel Mounting Surface Check

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION:

The use of non-GM original equipment wheels may cause:

Damage to the wheel bearing, the wheel fasteners and the wheel
Tire damage caused by the modified clearance to the adjacent vehicle components
Adverse vehicle steering stability caused by the modified scrub radius
Damage to the vehicle caused by the modified ground clearance
Speedometer and odometer inaccuracy

Replace any wheels that are bent or dented, or have excessive lateral or radial runout. Wheels with runout greater than specified may cause objectionable vibrations.

Replacement wheels must be equivalent to the original equipment wheels in the following ways:

The load capacity
The wheel diameter
The rim width
The wheel offset
The mounting configuration

A wheel of the incorrect size or type may affect the following conditions:

Wheel and hub-bearing life
Brake cooling
Speedometer/odometer calibration
Vehicle ground clearance
Tire clearance to the body and the chassis

It is recommended that an approved tire balancer capable of reading lateral and radial runout be used to perform this check following the tire balancer manufacturer instructions. If one is not available, perform the following procedure:

Courtesy of GENERAL MOTORS COMPANY

Thoroughly clean the wheel mounting surface (1) with a clean shop towel and denatured alcohol, or equivalent.
Use a straight edge 203 - 229 mm (8 - 9 in) in length (2). Place the straight edge (2) on the wheel mounting surface (1). Try to rock the straight edge (2) up and down within the wheel mounting surface (1).
For aluminum flat-mount wheels, repeat the procedure in step 2 on at least 3 - 4 different positions on the wheel mounting surface (1).
If you can rock the straight edge (2), the mounting surface (1) is bent and the wheel must be replaced.
Inspect the mounting wheel/nut holes for damage caused from over-torquing the wheel/nuts. Inspect for collapsed wheel/nut bosses. Inspect for cracked wheel bosses. Replace the wheel if damage is found.
Courtesy of GENERAL MOTORS COMPANY

For steel wheels, repeat the procedure in step 2 on at least 3 - 4 different positions on the wheel mounting surface (2).

NOTE:

The outer mounting ring is designed to be raised slightly above the inner mounting ring.

If you can rock the straight edge (1), the mounting surface (2) is bent and the wheel must be replaced.
Courtesy of GENERAL MOTORS COMPANY

Inspect the mounting wheel/nut holes (1) for damage caused from over-torquing the wheel/nuts. Inspect for collapsed wheel/nut bosses. Inspect for cracked wheel bosses. If damage is found, the wheel must be replaced.
Replace the wheel if the wheel is bent.
Replace the wheel if the wheel/nut boss area is cracked.

Identify steel wheels with a 2 or 3 - letter code stamped into the rim near the valve stem. Aluminum wheels have the code, the part number, and the manufacturer identification cast into the back side of the wheel.