The Diamond T Model 306 is a truck of 1949 from the Diamond T Motor Car Company of Chicago. It appeared at the end of the decade in which the company rebuilt its commercial range after the war, when heavy trucks were sold by gross vehicle weight and annual model changes had been dropped.
Diamond T Model 306 at a glance
| Maker | Diamond T Motor Car Company, Chicago |
|---|---|
| Founded | 1905 by C. A. Tilt |
| Model | 306 |
| Year | 1949 |
| Post-war range | five models in 1946, fourteen in 1947 |
| Ratings from 1947 | chassis of 8,000–36,000 lb (3,600–16,000 kg) GVWR |
| Body styles | conventional, sleeper and cab-over-engine (COE) |
| Engines | Continental, Cummins and Hercules, petrol and diesel |
| Axles | single or tandem rear axles in many wheelbases |
| Model changes | annual changes discontinued; many models unchanged until 1950 |
| End of the name | merged with Reo in 1967 as Diamond Reo Trucks, Inc. |
Diamond T has no Wikipedia article on the Model 306; this page is based on the description of the company’s post-war commercial range in the article on Diamond T (based on one source).
History of the Diamond T Model 306
A Chicago truck maker
Diamond T was founded in Chicago in 1905 by C. A. Tilt. The company made touring cars of up to 70 hp until 1911 and then became a truck manufacturer; its own account says the name came from a logo designed by Tilt’s shoe-making father, a large “T” for Tilt framed by a diamond as a mark of quality. Trucks carried a hood emblem of a sled dog in harness. In the 1930s the range was steadily improved: a closed cab with doors and all-wheel hydraulic brakes came in 1928–1929, an all-steel cab with roll-up windows in 1933, and a V-style windscreen with mechanical updates in 1935. That cab served commercial and military trucks until it was replaced in 1951, so a truck of 1949 still wore it.
The post-war range
Commercial production had stopped in 1942 for military work; a few trucks were built again in 1944 and more in 1945. In 1946, the first full year of peace production, Diamond T had five models, and in 1947 fourteen. After the war heavy trucks were measured by gross vehicle weight rating, the total weight of the chassis, body and payload, and in 1947 the chassis were rated from 8,000 to 36,000 pounds (3,600 to 16,000 kg). Buyers could choose conventional, sleeper or cab-over-engine bodies, petrol or diesel engines from Continental, Cummins and Hercules, and single or tandem rear axles in many wheelbases. Annual model changes were discontinued and many models continued unchanged until 1950, which is why the 1949 Model 306 looked much like the trucks that preceded and followed it.
The last years of Diamond T
By 1967 the company was a subsidiary of White Motor Corporation and was merged with the Reo Motor Company to become Diamond Reo Trucks, Inc. The Model 306 belongs to the period in which the post-war generation of Diamond T trucks was at its most settled: a proven cab, a choice of engines and gearboxes, and ratings that covered everything from light haulage to the heaviest loads on offer.
Design and features
- Settled design: with annual model changes dropped after the war, the 1949 truck differed little from the 1947 range.
- Three engine suppliers: Continental, Cummins and Hercules, in petrol and diesel form.
- Rated by weight: chassis ratings ran from 8,000 to 36,000 lb gross vehicle weight.
- Body choice: conventional, sleeper or cab-over-engine layout.
- Proven cab: the all-steel cab of 1933, with its 1935 V-style windscreen, stayed in use until 1951.
Diamond T Model 306 versions
- Conventional: the standard bonneted layout with the cab behind the engine.
- Sleeper: a conventional truck with sleeping space in the cab.
- Cab-over-engine: the short-wheelbase alternative.
- Tandem-axle chassis: two rear axles for the heaviest gross vehicle weights.
The earlier heavy trucks of the range are described in Diamond T 921, the later ones in Diamond T 969, and the company’s pickups in Diamond T Model 201. More vehicles are in the Diamond T collection.
Video: 1949 Diamond T model “306” lets ride!
Video on YouTube.
Sources
- Diamond T, English Wikipedia: post-war range, ratings, engines, company history
- 1949 Diamond T Model 306, YouTube: identification of the model and year in the film
