The Rolls-Royce 20/25 was the second of Rolls-Royce Ltd's pre-war entry level models. Built between 1929 and 1936, it was tremendously popular, becoming the most successful selling inter-war Rolls-Royce. Its success enabled Rolls-Royce to survive the economic difficulties of the Great Depression years and remain one of world's great brands. A total of 3,827 20/25s were produced, of which over 70% are still on the road today.
The 20/25 was the successor of the highly successful 20 hp Rolls-Royce Twenty introduced in 1922. The target market for the 20/25 was the same as the Twenty – the luxury, owner driver market. The project to develop the next generation 20 hp was code named Goshawk. The goal for the new model was to increase power & performance. This was achieved by increasing the bore size from 3 to 3.25 inches. The stroke was unchanged at 4.5 inches. This resulted in a 17% increase in capacity from 3128 to 3675cc – bring the RAC rating up to 25.4 hp.
The new 20/25 model was debuted at the 1929 Olympia Motor Show and proved to be tremendously popular becoming the greatest of the inter-war successes. There were 3827 20/25 hp produced – over twice the number of its contemporary sibling the Phantom II. The popularity of the 20/25 saved Rolls-Royce Limited during the pre-war economically difficult years. Ultimately 20/25 model was replaced by the 25/30 model in 1936 in which the bore was further increased to 3.5 inches. In 1938 the 25/30 was given a new chassis with independent front suspension and was renamed the Wraith.
The 20/25 also enabled Rolls-Royce Ltd to quickly capitalize on its 1931 acquisition of Bentley Motors Ltd. As part of integrating its acquisition, Rolls-Royce management discontinued the Bentley 8-Litre car due to the perceived market overlap with the Phantom II.