Segway PT x2 Reference Manual page 97

WARNING!
The tire pressure stated on any affixed Wheel label (near the
inflation valve) supersedes any recommended pressure stated
on the Tires.
Higher pressure reduces suspension performance and
traction, and increases risk of loss of control, collisions, and
falls.
Lower pressure reduces range and increases risk of damage to
the Tire/ Wheel Assembly.
Unequal pressure causes the Segway PT to turn in the
direction of the lower pressure tire.
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