27 A lot of semi trailers have these valve stem caps on their tires. if you happen to find one on a truck, you can use it to loosen or remove all the valve stems on YOUR truck, making YOUR truck harder to remove... (media.greatawakening.win) posted 2 years ago by VaccinesCauseSIDS 2 years ago by VaccinesCauseSIDS +27 / -0 8 comments download share 8 comments share download save hide report block hide replies
Well they probably have portable air compressors to refill to tires.
I have one for my car fits in my glovebox. I know it wouldn't work on a semi but it's certainly works on my Chevy and on my daughter's truck tires.