Which modifications to the front end suspension lead to rejection during inspection?

The use of shims for alignment can lead to rejection during inspection because shims can alter the intended geometry of the suspension system. While shims are sometimes utilized to adjust the alignment to bring a vehicle back to specifications, improper installation or excessive use of shims may indicate misalignment issues that aren't being addressed correctly. This can compromise the vehicle's handling, stability, and tire wear, which are critical components of safe vehicle operation.

In regard to other modifications, such as the use of lift blocks or an overall suspension height increase, while they can affect vehicle dynamics and ride quality, they may still be permissible under certain conditions if they comply with state regulations. The use of unapproved aftermarket parts may also lead to rejection depending on whether those parts meet safety standards, but the specific concern with shims lies in their impact on alignment integrity and overall suspension performance.

Understanding the specifics regarding modifications and their potential effects on vehicle safety is essential for ensuring that vehicles remain compliant during inspections.