While diagnosing a vehicle that has a tendency to bump steer, which of these should be checked first?

In diagnosing a vehicle that exhibits bump steer, checking the wheel setback first is critical because it directly affects the vehicle's handling and steering response when encountering bumps in the road. Wheel setback refers to the position of the steering axis relative to the centerline of the wheel. If the steering axis is misaligned, it can result in an improper angle when the suspension compresses, leading to the steering wheel moving unexpectedly, which is characteristic of bump steer.

By addressing wheel setback initially, you can assess how much of an impact it has on the vehicle's steering behavior. If the wheel setback is within specifications and properly aligned, then you can move on to investigate the other components, such as wheel alignment, tie-rod ends, and steering gear, which also play important roles but might not be as directly linked to the symptoms of bump steer.

In summary, starting with wheel setback allows for an effective and systematic approach to diagnosing bump steer, ensuring that fundamental issues with the steering geometry are identified before evaluating other components.