12 • Important: Always read and follow the operating instructions.
Stages of In
fl
ation on a
Conventional Tire and Rim
Review these descriptions and diagrams carefully. Refer to them as
necessary during bead sealing, bead seating, and infl ation to verify
that you are proceeding properly and safely.
Bead Sealing
Bead sealing is the process of capturing air pressure between the
tire and the rim. The tire will usually contain about 1/2 to 2 PSI at initial
bead seal
Bead Seating
Bead seating usually occurs on the long tapered side of the wheel
fi rst and the shorter side last. Bead seating will usually require at least
7 PSI in the tire. 40 PSI is the maximum safe pressure at this stage
regardless of tire operating pressure.
Most European import cars and many aftermarket alloy wheels are
very tight and can be diffi cult to bead seat. Also note that asymmetri-
cal hump and run-fl at tires are extremely diffi cult to bead seat. Follow
tire manufacturer’s recommended procedure for bead seating.
Infl ation
After the beads are seated, the tire is ready to be infl ated. Do not
infl ate the tire above the manufacturer’s recommended pressure as
stamped on the tire sidewall. The typical infl ation pressure for auto-
mobile tires is between 24 and 45 PSI. Light truck infl ation pressure
typically covers a wider range.
Air fl ow through valve requires about
140 PSI air pressure drop to ensure
suffi cient fl ow on diffi cult tires.
Usually last to “pop” is the mount side.
Requires visual
conformation of
bead seat.
Stand clear of the tire during bead seat and infl ation.
Stand clear of the tire during infl ation.
Requires rubber lu-
bricant on both upper
and lower beads.
Make sure the tire bead is
not obstructing air fl ow
from the valve stem
into the inside of
the tire.
