What is "sag" commonly a sign of in vehicle structural analysis?

"Sag" in vehicle structural analysis is primarily an indicator of damage, particularly after an impact on the frame rails. When a vehicle experiences a collision, the frame may become bent or altered, leading to sagging in certain areas. This deformation prevents the vehicle from maintaining its intended shape and height, causing sections of the body or frame to sag below normal levels.

Additionally, sag can signify compromised structural integrity, which can affect the vehicle's safety and performance. Identifying sag is crucial in the evaluation process as it helps technicians pinpoint areas that need repair or reinforcement to restore the vehicle to its proper condition and ensure safe operation. The distinction here is that while other factors such as weight load and tire pressures can affect vehicle height or handling, sag is most directly associated with structural damage from impacts, making it an important sign for technicians during inspections.