The Diamond, and the R.A.C.: the Ricketts continued under a new name

1910 — 1912

The marque: The Diamond Automobile Company of South Bend succeeded the Ricketts works, and Georgano's encyclopedia states the relationship in one sentence: "The Diamond was a continuation of the Ricketts." The car it sold was the Ricketts idea at full size — a fifty-horsepower six-cylinder, produced in three body types, among them a five-seater touring car priced at 2,200 dollars. During 1911 and 1912 the car was referred to as the R.A.C., "apparently in memory of the Ricketts Automobile Co.," as Georgano gives it. Doyle's register carries the marque under that later name only — "R.A.C. — Diamond Automobile Co. — South Bend, Ind. 1911–1912" — while Georgano dates the Diamond itself 1910–1912; both datings stand here as the two references print them, and the difference is a year at the front of a three-year life, not a dispute about the car. With the Diamond the city's independent field closes: no South Bend maker outside the Studebaker orbit is documented after 1912 until the corporate era taken up below. One name-trap is disposed of here: the Diamond of South Bend is not the Diamond T of Chicago, the truck maker — no relation appears in either company's record.

Sources:

1. Georgano, The Complete Encyclopedia of Motorcars, Diamond entry, as carried in the prewarcar marque register — the Diamond Automobile Co. of South Bend, 1910–1912, the continuation of the Ricketts, the fifty-horsepower six in three body types, the five-seater touring at $2,200, the R.A.C. renaming of 1911–1912 and its stated reason.
2. Doyle, The World's Automobiles, full text read first-hand (Internet Archive) — the register's listing of the marque as "R.A.C.," Diamond Automobile Co., South Bend, 1911–1912.