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, and resistance to rollover may be affected. If the vehicle has electronic systems such as antilock brakes, rollover airbags, traction control, and electronic stability control, the performance of these systems can also be affected.

WARNING
If different sized wheels are used, there may not be an acceptable level of performance and safety if tires not recommended for those wheels are selected.
This increases the chance of a crash and serious injury.
Only use GM specific wheel and tire systems developed for the vehicle, and have them properly installed by a GM certified technician.

See Buying New Tires and Accessories and Modifications.