Background
Any car good enough for Land Speed Record hero Sir Donald Campbell is good enough for us, and he owned a 20/25. And as Sir Don would surely have appreciated, its predecessor the 20, was in need of a performance hike. So the new model’s engine was enlarged from 3.1 to 3.7-litres, giving the 20/25 significantly more acceleration in the process.
The 20/25 was the second of Rolls-Royce’s pre-war entry level models. Built between 1929 and 1936 it was tremendously popular, becoming the most successful selling inter-war car built by the world famous Derby-based company. 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 a staggering 70% are still on the road today.
The new model utilised the chassis of its predecessor, the 20, but improved power had become a necessity because owners often insisted on fitting elaborate and heavy coachwork, which severely affected the cars’ performance. This was an important change – Rolls Royce owners didn’t like to be overtaken by what they believed to be inferior cars.
An Autocar report in 1931 describes the 20/25: 'Every single feature spells durability, the machine is on a plane altogether superior to the normal style of motor car'. This claim is backed up by the fact that this model was the choice of some of the most famous drivers of the day. Aside from Campbell, other racing drivers with 20/25s included Tommy Sopwith and Prince Bira of Siam.
The 20/25 kept the Rolls-Royce tradition of a two-model policy, being sold alongside of the Phantom II. It was offered as a more economical car and was smaller than its sibling. All of the 20/25HP were outfitted with custom coachbuilt bodies from legendary names such as Park Ward, Vanden Plas, Freestone and Webb, Brewster, Gurney Nutting, Park Ward, Coachcraft, and Thrupp & Maberly.
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 due to the perceived market overlap with the Phantom II. This meant the acquisition brought with it the Bentley brand, debt and engineers & manufacturing employees – but no product to produce.
The engine was a 3699cc straight-six with overhead pushrod operated valves, featuring a cast iron block with an aluminium crankcase. The single cast iron cylinder head sat atop the assembly with a single spark plug per cylinder. The typically British long stroke design also incorporated a seven main bearing crankshaft with a vibration damper and pressure fed lubrication, with a relief valve feeding the rocker shaft and timing gears. Heady stuff for 1929.
Mated to this was a four speed manual gearbox with synchromesh on third and fourth gears, and a single plate dry clutch – again, advanced stuff for the time, pushing Rolls to the top of the technology tree. On top of that, the new model had brakes on all four of its wheels, and they were even servo assisted.
With nearly 4000 chassis created the 20/25 was one of Rolls-Royce's best selling contemporary models, lasting from 1929 through 1936. During the production lifespan of the 20/25, the car was constantly updated. The ignition, brakes, clutch, and carburettors were just a few of the mechanical areas to receive modifications and improvements.
In 1936 the 20/25 was superseded by the 25/30.
