What is a common cause of heavy steering in a vehicle?

Heavy steering is often attributed to under-inflated tires. When tires are not properly inflated, they create more rolling resistance against the road, making it require more effort to turn the steering wheel. This additional friction can lead to a feeling of heaviness when steering, especially at lower speeds.

On the other hand, having over-inflated tires can lead to a different set of handling issues, but it typically does not cause a heavy steering sensation. Worn-out brake pads primarily affect braking performance rather than steering feel. A loose steering wheel would lead to a lack of responsiveness or control rather than an increased effort in steering. Thus, under-inflated tires are the primary cause of heavy steering due to the additional resistance they produce.