Installation Manual

MN-420
13
TUNING THE AIR PRESSURE
Pressure determination comes down to three things — level vehicle, ride comfort and
stability.
1. Level vehicle
If the vehicle’s headlights are shining into the trees or the vehicle is leaning to one side,
then it is not level (fig. E.1). Raise the air pressure to correct either of these problems
and level the vehicle.
2. Ride comfort
If the vehicle has a rough or harsh ride it may be due to either too much pressure or not
enough (fig. E.2). Try different pressures to determine the best ride comfort.
3. Stability
Stability translates into safety and should be the priority, meaning the driver may need
to sacrifice a perfectly level and comfortable ride. Stability issues include roll control,
bounce, dive during braking and sponginess (fig. E.3). Tuning out these problems
usually requires an increase in pressure.
GUIDELINES FOR ADDING AIR
1. Start with the vehicle level or slightly above.
2. When in doubt, always add air.
3. If the front of the vehicle dives while braking, increase the pressure in the front air bags, if
equipped.
4. If it is ever suspected that the air bags have bottomed out, increase the pressure (fig. E.4).
5. Adjust the pressure up and down to find the best ride.
6. If the vehicle rocks and rolls, adjust the air pressure to reduce movement.
7. It may be necessary to maintain different pressures on each side of the vehicle. Loads
such as water, fuel, and appliances will cause the vehicle to be heavier on one side (fig.
E.5). As much as a 50 PSI difference is not uncommon.
Bad headlight aim
Sway and
body roll
Rough ride
g. E.1
g. E.3
g. E.2
Bottoming out
Unlevel
Level
g. E.4 g. E.5
RideControl