It is important to use the correct size rim for your car, as using a rim that is too large or too small can affect the performance and safety of your vehicle. Using a rim that is too large can cause the tires to rub against the wheel wells or suspension components, which can damage the tires or cause the vehicle to handle improperly. Using a rim that is too small can cause the tires to be underinflated, which can lead to problems such as reduced traction, increased wear and tear on the tires, and potential damage to the wheels.