In the late 1940s, the military and civilian structures of the Soviet Union faced an acute problem: it was necessary to establish the transportation of heavy equipment, primarily tanks, over long distances without wearing out their own power plants. The experience of operating American tractors, such as the Diamond T-980, Federal 604, and Federal 606, supplied under the Lend-Lease program, showed the high efficiency of multi-axle heavy-duty road trains. However, the imported equipment was gradually depleting its resources, and the country needed its own alternative.
It was under these conditions that the YAZ-210G ballast tractor appeared in the line of three-axle trucks of the Yaroslavl Automobile Plant.
The first prototype of the vehicle was assembled on October 17, 1948. The design was based on a chassis unified with other members of the YAZ-210 family, but it was significantly redesigned to operate as part of a heavy road train. In general, this family was considered one of the most heavy-duty in the USSR of the late 1940s and was intended for operation in difficult road conditions with a total weight of the road train exceeding 30 tons.
Design changes included:
- shortening the wheelbase by 970 mm (to 4780 mm compared to the flatbed version)
- reducing the rear overhang of the frame by 1000 mm
- shifting the transfer case forward by 359 mm
- shortened cardan shafts to the rear bogie
To increase traction, engineers changed the gear ratios. In the reduction gear, the constant gear was increased from 1.07 to 1.41, which provided a final gear ratio of 11.6. This significantly increased traction on the drive wheels, a critical parameter when starting a road train weighing tens of tons.
As a result, the maximum speed in overdrive decreased to 45 km/h. However, for the conditions of that time, this was considered acceptable: columns of heavy equipment usually moved at an average speed of about 30–35 km/h. The estimated payload of the trailer was 25 tons, with the main loads falling on the engine and transmission, while the chassis was designed for the level of the base truck.
Special attention was paid to increasing the adhesion weight. The tractor received a ballast platform with a volume of 4.9 m³ with a folding tailgate. Metal blocks, stone, or concrete were loaded into it, which made it possible to increase the adhesion of the drive wheels to the road.
Equipment layout included:
- two front compartments for spare wheels
- a lifting boom with a block for their maintenance
- a winch borrowed from the YAZ-210A, with the cable output forward and backward
The winch allowed not only to drag equipment onto the platforms of heavy-duty trailers, but also to use the tractor for self-extraction. Fuel consumption at full load was estimated at approximately 100 liters per 100 km, a figure comparable to American counterparts that consumed 90–110 liters.
In 1949, the only YAZ-210G unit, along with a 40-ton 4R-1372 three-axle heavy-duty trailer, was sent for interdepartmental testing. They revealed a significant number of shortcomings, both structural and manufacturing in nature. Over the next two years, both the tractor and the trailer were refined.
Repeated tests started at the end of May 1951. The updated tractor received an experimental 200 hp engine, and the trailers were equipped with 14-ply tires of size 8.25–20, which allowed increasing the payload to 45 tons. However, even before the start of testing, a serious breakdown occurred: the crankshaft failed, requiring a major engine overhaul.
Additionally, the following improvements were made:
- installation of front suspension shock absorbers
- replacement of cardan shafts
- adjustment of units
Despite this, the commission again noted insufficient refinement and problems with the quality of manufacture.
Nevertheless, serial production began in the fourth quarter of 1951: 11 vehicles were produced by the end of the year. Delays in the development of the YAZ-206 engine did not stop the process, as the need for tractors remained extremely high.
State acceptance tests of serial samples took place in 1952 (on chassis No. 417 and 430). They were largely formal, as the equipment was already entering the troops. At the same time, the vehicles received a number of improvements:
- chrome-plated upper compression rings
- ST-26 starters
- heating systems for winter starting
Despite the improvements, the list of comments remained significant. However, the conclusion emphasized the need to continue production due to the acute shortage of such equipment.
The key problem of the entire YAZ-210 family remained the engine. Even the modernized version of the YAZ-206A by 1953 did not provide the declared resource of 20 thousand kilometers. The main malfunctions concerned the piston group, drive, speed controller, and clutch.
The experimental 200-horsepower engine was never put into production, so all YAZ-210G were equipped with 165-horsepower units, which worked with overload as part of heavy road trains.
Over time, the design of the machine changed. The first production copies were equipped with American winches, but since 1952 their installation ceased due to the depletion of stocks and the lack of their own production.
By 1953, changes affected the layout:
- spare wheels were moved between the cab and the platform
- the platform design was redesigned
- wooden extension boards, benches, and an awning were added
The main customer for the tractors was the Ministry of Defense, but the equipment also found application in the civilian sphere. In particular, the YaAZ-210G was used in airports to tow jet aircraft, the mass of which exceeded the capabilities of standard airfield tractors, as well as in construction for transporting heavy equipment.
Production continued until 1958, after which the production of the entire YaAZ-210 family was discontinued. They were replaced by more modern KrAZ-214 vehicles and subsequent models of the Kremenchug Automobile Plant, which inherited a number of design solutions.
According to archival data, a total of 2303 YaAZ-210G ballast tractors were produced, including the first prototype. The machine became an important stage in the development of Soviet heavy automotive equipment, despite the numerous problems identified during operation.