Four-wheelin typically starts out with the ritual of turning in the hubs and airing
down the tires, Airing down tires usually results in playing the
"press the valve core in with your key and wait forever game" or
you remove the core and sometimes play the "where did the valve core go game"
Playing these games to many times makes you start looking at tire deflation systems.
With the J-flaters you will find typically that, no matter what your tire size is, with a little timing and practice, you can get them all down to wheeling pressure in under 5 min.
If, and only if, you are unlucky enough to get the valve stems that stick right out the side of your rim here is our easy video on how to move them in under 2 minutes.