How can you tell if a tire is under-inflated?

A tire that is under-inflated will often appear flat and may have a noticeable bulge at the sides. When the pressure is low, the tire is unable to maintain its shape properly, leading to a flatter, more distorted appearance. This bulging occurs because the tire isn't able to support the weight of the vehicle as intended, resulting in excessive flexing of the sidewalls.

This can significantly affect vehicle handling, increase tire wear, and reduce fuel efficiency, making it crucial for drivers to regularly check tire pressures and look for visual signs of under-inflation. While other options may indicate issues with the tire, they do not specifically highlight the characteristic appearance of under-inflation like the bulging edges do.