The Mack DM series was the extra-heavy-duty member of the R family. It used the offset “Commandcab” of the U series, with the driver’s door in the same vertical plane as the side of a trailer, and was most often ordered as a 6×4 construction truck.
Mack DM series at a glance
| Maker | Mack Trucks |
|---|---|
| Based on | Mack U series, with the offset Commandcab |
| Typical layout | 6×4 construction truck |
| Cab | offset to the left, engine doghouse alongside the passenger |
| DMM version | all-wheel drive, short hood, set-back front axle |
| DMM hood | model-specific fibreglass hood-and-fender unit |
| Cab length | 89 in bumper-to-back-of-cab on the U series |
| End of production | scheduled to be built into 2004 |
| Assembled | Macungie, Pennsylvania |
The DM is described in the development and production history sections of the English Wikipedia article on the Mack R series; there is no dedicated DM article.
History of the Mack DM series
The DM grew out of the U series, the short-cab derivative of the R that Mack designed to cut the bumper-to-back-of-cab length. The U’s trick was an offset cab, called the Commandcab, that placed the driver’s door in the same vertical plane as the side of the trailer; to make room for the engine, a doghouse intruded into the passenger footwell while the driver’s position stayed where it was. The U replaced the earlier C series with a cab only one inch longer (89 inches against 90) but with the improvements of the R cab.
The DM took that layout and turned it into an extra-heavy-duty truck, usually a 6×4 for construction work with a dump body or a mixer. The DMM was the all-wheel-drive member of the family: like the RMM it drove through all its axles, but it also had a short hood, the offset cab and a set-back front axle, which meant it needed its own fibreglass hood and fender arrangement. The DM family proved long-lived. While the highway R models were replaced by the CH and CL in the 1990s, the severe-duty derivatives kept going, and Mack was still scheduling the RB and the DM for production in 2004; the RD and RM ended in late 2003 as 2004 models.
Design and features
- Offset Commandcab: the driver sits close to the trailer line, with the engine doghouse beside the passenger.
- 6×4 construction chassis: the typical DM was a tandem-axle truck for dump and mixer work.
- All-wheel-drive DMM: full traction for site work, with a short hood and set-back axle.
- Long production life: the severe-duty R derivatives outlasted the highway models by a decade.
Mack DM series versions
- DM600: the standard extra-heavy-duty construction truck.
- DM800: the heavier rating in the same family.
- DMM: all-wheel drive with a model-specific fibreglass hood and set-back front axle.
- DM (late production): still scheduled for building into 2004.
The DM came from the Mack U series, which itself was a short-cab version of the Mack R series. The truck that finally replaced the severe-duty R models was the Mack Granite. More trucks are in the Mack collection.
Sources
- Mack R series, English Wikipedia: the U and DM series, DMM layout, end of production
- Mack Trucks, English Wikipedia: company history and plants
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