Cadillac 2010 DTS - Manual (Page 381)

High-Speed Operation
{ WARNING:
Driving at high speeds, 160 km/h (100 mph)
or higher, puts an additional strain on tires.
Sustained high-speed driving causes excessive
heat build up and can cause sudden tire failure.
You could have a crash and you or others could
be killed. Some high-speed rated tires require
inflation pressure adjustment for high speed
operation. When speed limits and road conditions
are such that a vehicle can be driven at high
speeds, make sure the tires are rated for high
speed operation, in excellent condition, and set
to the correct cold tire inflation pressure for the
vehicle load.
If your vehicle has P235/55R17 or P245/50R18 size
tires, and you will be driving at speeds of 100 mph
(160 km/h) or higher, where it is legal, set the cold
inflation pressure to the maximum inflation pressure
shown on the tire sidewall, or 38 psi (265 kPa),
whichever is lower. See the example following.
Example:
You will find the maximum load and inflation pressure
molded on the tire's sidewall, in small letters, near the
rim flange. It will read something like this: Maximum
load 690 kg (1521 lbs) @ 300 kPa (44 psi) Max. Press.
For this example, you would set the inflation pressure
for high‐speed driving at 38 psi (265 kPa).
When you end this high-speed driving, return the tires
to the cold inflation pressure shown on the Tire and
Loading Information label. See Loading the Vehicle on
page 5‑18.
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