Buick RIVIERA 1993 Manual page 214

Now put all the equipment back securely
in
the trunk.
Compact Spare Tire
Although the compact spare was fully inflated when
your vehicle was new, it can lose air after a time. Check
the inflation pressure regularly. It should be 60 psi (420
kPa). The compact spare is made to go up to 3,000 miles
(5000 km), so you can finish your trip and have your
full-size tire repaired or replaced where
you want. Of
course, it's best to replace your spare with a full-size tire
as soon as you can. Your spare will last longer and be in
good shape in case you need it again.
Your anti-lock brake system warning light may come on
when you are driving with a compact spare. See
"Anti-Lock Brake System Warning Light" in the Index.
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