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50 years ago: Launch of the first ex-factory COE truck – the LP 315 – by Daimler-Benz

Apr 26, 2005
  • Large cab with two bunks
  • High payload capacity and easy maneuverability
  • Design oriented to bus styling
For a long time, Daimler-Benz had been extremely skeptical vis-à-vis the cab-over-engine design but then, in the mid-1950s, the company did finally ventured into adopting this design principle that was favored by a growing number of – predominantly – foreign customers. The first ex-factory COE truck, the LP 315, made its debut in June 1955. The basic vehicle had been no lesser truck than the long-distance bestseller L 315, derived from the L 6600 which in turn had been the first newly designed truck after the war.
The key features of the L 6000 had included a short cab with decidedly spartan appointments, a payload capacity of initially 6.2 tons (L 6600, model year 1950) and later raised to 7.2 tons (L 315, model year 1954), and the OM 315 pre-chamber diesel engine with 145 hp. In the course of time, it had been planned to fit the conventional L 315 with a long-distance truck cab, and the Daimler-Benz engineers, cooperating with colleagues from Wackenhut, had come up with a kind of short-nose truck whose engine protruded some way into the cab.
The engineers had hoped to create a long-distance truck cab in this way without any reductions in platform size. However, the new development did not go any further than the prototype stage. The principle was nevertheless adopted for the short-nose trucks of which Daimler-Benz was to build both heavy-duty and medium-duty versions from 1958. Daimler-Benz even used this design for the modern vans of the T1 generation, which were to come off the assembly lines at the Düsseldorf plant from 1977.
Seats and pedals moved forward
Anyone wishing to have the conventional L 315 as a cab-over-engine truck with a long sleeper cab had no choice but to tackle the conversion work themselves or have it done by specialists. Companies like Wackenhut, Schenk, Kässbohrer and Kögel specialized in converting conventional chassis into cab-over-engine trucks and fitting their own cabs and superstructures. This involved a lot of work which did not end with the forward movement of the seats and setting the steering column at a steeper angle. The pedals had to move forward too, and the gearshift linkage had to be modified accordingly.
Despite the skepticism vis-à-vis the COE design, it was therefore only logical for Daimler-Benz to offer vehicles in this design ex factory at last. The decision was made easier in the mid-1950s by the major increase in international demand for COE trucks as well as by forthcoming, highly restrictive dimensional and weight regulations which significantly boosted interest in the COE configuration in Germany.
As before, the letter “L” in the model designation of the LP 315 stood for “Lastwagen” (the German word for truck), while the newly added letter “P” denoted “Pullman”, a term used in the American railway industry. The streamlined passenger trains designed by inventor George Mortimer Pullman had once caused quite a sensation in the USA and become known as Pullman trains.
Cab supplied by Wackenhut
Pullman cabs, which had solely been destined for export initially, were supplied to the Gaggenau plant from just the other side of the Black Forest. But it wasn’t long before the first units were also operating on German roads with German number plates. Wackenhut, a company headquartered in Nagold, had developed long sleeper cabs in accordance with Mercedes-Benz specifications and continued to build the first COE cabs for several years before Daimler-Benz engaged in in-house manufacture.
Softly rounded contours gave the cab a likeable appearance, reminiscent – probably quite intentionally – of the front-end styling of Mercedes-Benz buses. For the driver, however, the COE design was a drawback in that an engine tunnel now protruded imposingly into his cab and the engine made itself heard quite resoundingly in its new location.
Seating for four plus two bunks
On the other hand, the large cab provided the driver with a level of luxury that was not to be found in the short cab of the conventional L 315. In its rear section, the LP cab accommodated two bunks: “During breaks or at night, the rear seats can easily be converted into two comfortable beds,” said a contemporary brochure in listing the advan-tages of the long cab. In those days, the driver was rarely alone in the truck, and so it was a benefit that the LP cab “offers generous space for four people,” as the brochure emphasized.
The new COE design also had economic advantages in that the factory was able to supply the trucks with a six-meter-long platform as standard, courtesy of the compact cab. By comparison, the conventional L 315 had a standard platform which was merely five meters long.
LP 315: Top-league player in the payload category
What’s more, a slightly shorter wheelbase length as compared to the conventional truck (4,200 vs. 4,600 millimeters) also benefited pay-load capacity. The advertising put it in a nutshell: “Even more favorable axle loading.” For the LP 315, this translated into a respectable pay-load capacity of 8.2 tons – clearly more than that of the conventional L 315. With this payload, and notwithstanding its permissible gross vehicle weight of 14,900 kilograms, the LP 315 soon played in a very different league, one from which the conventional truck had been barred: the league of expensive flagships with a gross vehicle weight of 16 tons and engines in the 180 – 200 hp range, the domain of as many as six German manufacturers. Such a 16-tonner cost around DM 50,000 whereas the LP 315 was to be had at a price as low as roughly DM 35,000. In those days, the difference of DM 15,000 corresponded to the price of a complete three-axle trailer.
“Roofed” engine maintenance
In addition, the compact design of the LP 315 and its shorter wheel-base translated in greater ease of maneuvering. While the conventional truck had a turning circle of 18.5 meters, that of the LP 315 was a mere 17 meters. In terms of maintenance and repairs, however, the rigidly mounted cab of the LP 315 was clearly inferior to the extremely easy-to-service conventional truck. The company did praise the advan-tage of effortlessly servicing the engine from inside the cab, under “ roofed” conditions, so to speak. But the heavy engine cover, attached to the rear wall by means of hinges, had to be folded away even for a job as ordinary as topping up the engine oil. An exercise which became second nature to the driver quickly as the OM 315 consumed 0.4 liters of oil per 100 kilometers according to the company. The brochure claimed that it was even possible “to remove the cylinder head from the engine in installed condition.” But when major repairs were required on the LP 315’s engine, there was no alternative to pulling out the six-cylinder diesel engine toward the front.
Wide range of versions
This first cab-over-engine truck remained in production until 1957. The LP 315 was available with different wheelbase lengths, as a platform truck, dump truck, semitrailer tractor and chassis, strictly retaining the proven technical ingredients of its conventional L 315 brother not just in terms of the engine but also in all other respects: six-speed constant-mesh transmission, a top speed of 70 km/h and a U-section frame with pressed sheet-steel cross members.
The first ex-factory COE truck nevertheless met with hesitant response. Whereas the plant produced 13,735 units of the conventional L 315 between 1950 and 1958, the cab-over-engine LP 315 reached a volume of just 2,480 units before production was discontinued in 1957.
Highly comfortable by contemporary standards: The interior of the Mercedes-Benz LP 315 with two bunks, 1955.