Which component of a stepladder is primarily used for structural support?

The side rails of a stepladder serve as the primary structural support components. They form the main framework of the ladder and provide stability and strength when the ladder is in use. The side rails are typically made of durable materials designed to bear weight and resist bending or breaking under load.

While other components like the spreader contribute to the ladder's stability by keeping the side rails apart when the ladder is in use, they do not bear the weight in the same way as the side rails do. The top cap is important for additional functionality, such as holding tools or providing a resting point, but it does not contribute to the structural integrity of the ladder itself. The feet provide grip and stability on the ground but are not designed to support the weight of the user. Therefore, the side rails are crucial as the main support structure of the stepladder.