why not just buy a $9 portable tire pump air
compressor? Then when you take your spare out,
you can fill it up wherever you happen to be? Or
if you have a slow leak you can just fill up the
tire and drive to the nearest tire repair shop.

Mine fits under the trunk thing, along with a $10
bottle jack that works a billion times better
than that cheapass scissor jack they give you.
unless its minus 90 outside... Then I stick
to the scissor jack.

t