GMC 2014 Yukon/Yukon XL Owner's Manual page 414

Do not mix tires and wheels of
different sizes, because they will not
fit. Keep your spare tire and its
wheel together. If your vehicle has a
spare tire that does not match your
vehicle's original road tires and
wheels in size and type, do not
include the spare in the tire rotation.
For more information about the
vehicle battery, see
.
If the vehicle's battery (or batteries)
has run down, you may want to use
another vehicle and some jumper
cables to start your vehicle. Be sure
to use the following steps to do it
safely.
Batteries can hurt you. They can
be dangerous because:
They contain acid that can
burn you.
They contain gas that can
explode or ignite.
They contain enough
electricity to burn you.
If you do not follow these steps
exactly, some or all of these
things can hurt you.
1. Check the other vehicle. It must
have a 12-volt battery with a
negative ground system.
2. Get the vehicles close enough
so the jumper cables can reach,
but be sure the vehicles are not
touching each other. If they are,
it could cause a ground
connection you do not want. You
would not be able to start your