When It Is Time for New Tires
Factors such as maintenance, temperatures, driving speeds, vehicle loading, and road conditions affect the wear rate of the tires.

Treadwear indicators are one way to tell when it is time for new tires. Treadwear indicators appear when the tires have only 1.6mm (1/16 in) or less of tread remaining. See Tire Inspection and Tire Rotation for more information.
The rubber in tires ages over time. This also applies for the spare tire, if the vehicle has one, even if it is never used. Multiple conditions including temperatures, loading conditions, and inflation pressure maintenance affect how fast aging takes place. Tires will typically need to be replaced due to wear before they may need to be replaced due to age. Consult the tire manufacturer for more information on when tires should be replaced.
See also:
Different Size Tires and Wheels
If wheels or tires are installed that are a different size than the original
equipment wheels and tires, vehicle performance, including its braking, ride and
handling characteristics, stability, a ...
Compact Spare Tire
WARNING
Driving with more than one compact spare tire at a time could result in loss
of braking and handling. This could lead to a crash and you or others could be injured.
Use only one compact ...
Power Lumbar
On vehicles equipped with either a two-way or four-way
lumbar, the control is located on the outboard side of
the seats.
For a detailed operation description see Power Lumbar . ...
