In 1912, the purse was raised to $50,000, the field was limited to 33 (where it remains), and a riding mechanic was made mandatory. This second event was won by Joe Dawson in a National, after Ralph de Palma's Mercedes broke. Although the first race was won by an American driver at the wheel of an American car, European makers such as the Italian Fiat or French Peugeot companies soon developed their vehicles to try to win the event, which they did from 1912 to 1919. The 1913 event saw a change to a maximum engine size.