Your vehicle's suspension and underbody can be damaged if driven on rough/uneven roads or over speed bumps at excessive speeds. Use care and reduce speed when traveling on rough/uneven roads or over speed bumps.
Use care not to damage the vehicle's underbody, bumpers or muffler(s) when driving under the following conditions:

This vehicle is equipped with low profile tires allowing class-leading performance and handling. As a result, the sidewall of the tires are very thin and the tires and wheels can be damaged if driven through potholes or on rough/uneven roads at excessive speeds. Use care and reduce speed when traveling on rough/uneven roads or through potholes.
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TowingMazda 6 Owners Manual: Replacing a Wheel
WARNING
Always use wheels of the correct size on your vehicle: Using a wrong-sized
wheel is dangerous. Braking and handling could be affected, leading to loss of control
and an accident.
CAUTION
A wrong-sized wheel may adversely affect:
Tire fit
Wheel and bearing life
Ground clearance ...
Mazda 6 Owners Manual: Excessive Speed Warning
If the vehicle speed exceeds the speed limit sign displayed on the active driving
display, the warning sound is activated and the area around the speed limit sign
displayed on the active driving display flashes 3 times in amber, and if the vehicle
speed continues to exceed the displayed speed ...