The racing death of star Antonio Ascari in 1925, along with a number of serious and fatal accidents drove the AIACR (forerunner of the FIA) to consider changes to its racing regulations. In October of that year, they resolved to combat the dramatic increase in power and speed from supercharging by dropping the engine capacity from 2-litres to 1.5-litres (albeit still open to be fitted with or without a supercharger). The minimum weight was also reduced from 650 to 600 kg. The AAA Contest Board (AAA), in the United States, followed the change adopting similar rules, to an equivalent drop from 122 to 91 cubic inches. Minimum width remained 80 cm with two seats, though only one driver was on board.Cimarosti 1997, p.72
