While automotive experts recommend using four like tires on a vehicle, and specifically the type best suited for the vehicle, exceptions are allowable within certain limits. Within these limits and especially when the limits are exceeded, problems can occur — the effects proving as harmless as throwing off speedometer readings or as hazardous as creating steering, braking and handling issues. Damage to the vehicle can also result from tire variations.
Tire size can vary by width and height, and although a specific tire is usually recommended for a vehicle to perform optimally, there is a window of sizes that will work safely — roughly a 3 percent change in size for cars and 15 percent change for SUVs and trucks, according to Tire Rack. Within this window, effects are felt mostly in the steering, braking, acceleration and overall driveability.