Valve stems are made up of a body, core, and a cap. The valve core is the inner sealing portion of the valve stem that prevents air loss. The valve core should be tightened into the valve body for a proper seal.

While the valve cap helps prevent air loss with a rubber seal inside the cap, it’s main function is to keep dirt and debris from getting into the stem and contaminating or corroding the valve core. If moisture gets inside the valve stem and freezes, it can cause air loss and/or a flat tire.

The rubber components of valve stems can dry out and crack over time, causing air leaks or total air loss. To avoid this, we recommend replacing your valve stems at least every time you replace your tires.