Let's try to be clear: Extensions are some type of extender that screws onto the original rubber valve stem. They can unscrew with vibration underway and lose pressure . The weight of the device causes vibration of the rubber part of the original valve stem eventually causing it to crack and release tire pressure. "Solid brass or steel valve stems" are long enough and formed so that they protrude through RV beauty disks and allow easy access with any type of tire fill chuck in any position of wheel. IMHO they are needed on front wheels as well as rear dual wheels for easy valve access and pressure checking.
No frustrating release of pressure while checking it, no gymnastics required.
Some professional truck tire shops can make and install their own solid metal custom formed valve stems or install your Borg or Tire Man stems for you.