Pressurized VS Non-Pressurized Braided Steel Valve Extenders
Non-Pressurized Braided Steel Valve Extenders
Non-pressurized braided steel valve extenders have a pin and a long actuator rod running from the outer end of the valve, which resembles a valve core. Pushing on the valve core pushes the rod down through the tube to open the valve core bolted to your tire rim. A good way of knowing that you're using a non-pressurized braided steel valve extender is if it is difficult to retrieve air out of the extender, while pushing on the extender's valve core. From the manufacturer, these are often called "Airless" valve extenders.
Pressurized Braided Steel Valve Extenders
With a pressurized braided steel valve extender, the valve stem which is bolted to your tire rim is instantly opened once the extender is installed. Therefore, as soon as the valve extender is being screwed on, you should hear air escaping. The air flow should cease once the extender is properly tightened.
Wheel Masters - Valve Extenders
For an example of pressurized and non-pressurized braided steel valve extenders, please see Wheel Masters website: http://www.wheelmasters.com/inflators.html
Please note, non-pressurized valve extenders will not work with your TireMinder TPMS and need to be replaced in order for the transmitters to function properly. Because non-pressurized valve extenders do not allow a consistent flow of air to the transmitters, the transmitters are unable to provide proper readings. This will result in incorrect readings or no signal alerts.