Start with what the Rolls-Royce 25/30 is: a car with 4257 cc, built from 1936 to 1938, when streamlining and independent suspension were arriving together. What it meant takes a little longer.
How it came about
The Rolls-Royce 25/30 built between 1936 and 1938 is an updated version of the 20/25 with a larger engine to provide more power, as over-large bodies had often been fitted to the earlier model leading to complaints about its performance.
The hardware
The engine is 4257 cc. Drive goes through a 4-speed manual. The wheelbase is 132 in. These are manufacturer figures carried by Wikipedia and Wikidata, not road-test measurements.
Family and rivals
In the Rolls-Royce line-up the Rolls-Royce 25/30 has a clear place: it replaced the 20/25; it handed the line to the Wraith. The cars a buyer would have weighed it against include the Bugatti Type 57, the Volkswagen Beetle, the Chevrolet Suburban. Its Rolls-Royce stablemates include the Rolls-Royce 100EX and the Rolls-Royce 102EX.
Owning one today
There is no federal ownership record for the Rolls-Royce 25/30 — it predates the complaint database or was never sold in the United States — so MotorJury publishes no running-cost figure for it. For a car of this age the price is set by the collector market and the condition of the individual example, not by a formula.