Tire Wear

WARNING: This page is about a different car, the 2015 Kia Soul EV. However, it is still accessible from the selected car via links, so may be relevant.

Measure the tread depth of the tires.
Tread depth [limit]: 1.6 mm (0.0630 in.)
If the remaining tread depth (A) is less than the limit, replace the tire.
NOTE: When the tread depth of the tires is less than 1.6 mm(0.063 in), the wear indicators (B) will appear.

Fig 1: Tread Depth Dimension
Courtesy of KIA MOTORS AMERICA, INC.