Who is correct regarding the use of shims and strut rods for adjusting rear toe and camber?

The rationale for both technicians being correct lies in the fact that both shims and strut rods can play a role in adjusting rear toe and camber angles, which are critical for ensuring proper vehicle alignment and handling.

Shims are often used to make fine adjustments to the camber angle. By adding or removing shims, a technician can tilt the top of the wheel inward or outward, adjusting the camber based on the specifications required for the vehicle. This is particularly useful in achieving the desired handling and tire wear characteristics.

Strut rods, meanwhile, can be used to adjust the rear toe angle. By lengthening or shortening the strut rod, the technician changes the position of the rear wheel in relation to the vehicle, which affects the toe angle. Proper toe settings help ensure that the tires are aligned with each other and the direction of travel, ultimately leading to enhanced stability and tire longevity.

Given that both technicians have valid methods for adjusting these critical alignment angles—shims for camber and strut rods for toe—it's accurate to say both are correct in the context of their respective approaches to vehicle alignment adjustments.