Which condition might require checking the caster angle?

Checking the caster angle is particularly important when a vehicle seems to pull to one side. The caster angle is a vital part of the vehicle's suspension geometry that influences the stability and steering response. If the caster angle is off, it can cause uneven weight distribution across the front tires, leading to variations in how they contact the road. This can manifest as the vehicle pulling to one side since one wheel may have better contact or traction than the other.

While other conditions listed might be symptoms of suspension issues, they are not directly linked to the caster angle. For example, even tire tread wear might indicate a different kind of alignment issue, such as camber or toe misalignments, rather than a caster problem. Similarly, light steering could suggest an issue with the steering components or the weight of the vehicle rather than the caster angle itself. Increased road noise typically points to issues with tires or wheel bearings rather than any specific alignment checks. Hence, the scenario of a vehicle pulling to one side is a clear indicator that checking the caster angle is warranted to ensure proper alignment and handling.