Thomas B. Jeffery also manufactured bicycles before he took the gamble and started manufacturing motorcars. Jeffery, who emigrated from England, first built a motorcar in 1897 in Chicago. The model had a single-cylinder engine which powered the rear wheels via chains. At the end of the nineteenth century, Jeffery and his son Charles moved to Kenosha, where he specialised in the manufacture of motorcars. In 1902, the company already sold over 1,500 runabouts.
Rambler became one of America's most popular cars. 1905 saw the unveiling of the first model with a two-cylinder engine. In 1909, the last Rambler with such a two-cylinder engine rolled off the production lines. In 1910, the customer had a choice of two different four-cylinder engines, with either 34 or 45 bhp. The cars were definitely not cheap. One of the owners in that time was the American president William Howard Taft. Guarantees were unheard of in that era, but Jeffery had so much faith in his cars that he gave his customers full warranty for the first 10,000 miles. Thomas Jeffery died of a heart attack on 2 April 1910 during a holiday in Italy.
His son Charles then took over the business. Out of respect for his father he called the make Jeffery instead of Rambler from 1914 onwards.
Source: The complete encyclopedia of Vintage Cars - Rob de la Rive Box
The second largest manufacturer of cycles in America after the Columbia make of Colonel Pope was Rambler of Chicago. By 1902 Thomas B Jeffery had sold this cycle business to the Colonel, relocated to Kenosha, Wisconsin, and put into production a Rambler automobile. This was a conventional American runabout of the period, some 1500 being sold in the first year. A two-cylinder model with a horizontally-opposed underfloor engine was marketed in 1904 and this had more of a European look with a front radiator and wheel steering.
The Rambler factory was regarded as one of the best equipped automobile plants in America and turned Kenosha "from a prairie into a city", but Thomas Jeffery chose not to pursue a policy of mass-production. His unexpected death in 1910 brought the presidency of the firm to his son Charles who in 1914 changed the name of the cars to Jeffery. Charles retired in 1917 and sold the business to the Nash Motor Company that revived the Rambler name in 1950 for a twenty-year period.