Breaking in a new car in Las Vegas involves driving a vehicle in a slow-to-moderate pace so that the engine can get used to running. Although the manufacturer can break the car in, companies still recommend owners to drive below 5,500 RPM for the first 1,200 miles. How to Break in a New Car in Las Vegas First, each model has an ideal speed for breaking in a new car. The rough estimate is between zero and the mid-speed of the vehicle. It is unwise to floor the gas pedal in the first 1,200 miles. The primary purpose is to help the piston rings to settle well in the cylinder. The metal mixes with the engine oil leaving smooth pits.