Ural-5920

Ural-5920 at a glance

The plant's history is told in the story of the Ural factory, and its wheeled trucks from the Ural-375 to the Ural-4320 are in the Ural catalogue.

Why a tracked truck was needed

In the late 1960s the development of remote oil and gas fields needed vehicles that could carry heavy loads where no roads existed at all: across deep snow, bogs and thawing permafrost. Foreign companies already sold tracked carriers for such work. Buying them in large numbers was expensive, so the planners decided to develop a domestic carrier instead.

The task went to the snow-and-swamp vehicle laboratory of NAMI, the central automotive research institute. To speed up the work, the engineers tested several foreign all-terrain vehicles, among them the Canadian Foremost Husky. Field trials showed that the best layout for a cargo carrier was a vehicle frame resting on a pair of steerable track bogies. The imported carriers had a drawback: they were complex and needed skilled drivers and specialist maintenance. The new design had to be simpler and use as many parts as possible from trucks already in service, so that drivers and workshop staff would know most of the units.

NAMI-0157 prototypes and tests

The first prototype, the NAMI-0157BK, appeared in 1972. It borrowed heavily from the Ural-375 truck: the cab, bonnet, transfer case, cooling system, frame elements and a winch with a pulling force of 7,000 kg. The engine was the ZIL-375 petrol V8, and the driving axles also came from the truck family. The track bogies used double rows of rubber-tyred road wheels.

Tests revealed weak points, and two more vehicles, the NAMI-0157M, followed. The main change was single-row road wheels of larger diameter. They hardly clogged with mud, unlike the double rows, which had even caused tracks to come off, and they needed much less maintenance. According to the old 1cars text, the NAMI-0157M matched imported carriers and beat them on payload and running gear. It carried about 8 tonnes, reached around 30 km/h on dirt tracks, crossed swampy ground at speed and climbed 30-degree slopes.

From the 1974 order to small-series production

After interdepartmental tests in 1974, the automotive ministry ordered on 5 February 1974 that the tracked carrier should go into production at the Ural Automobile Plant. The production version, the Ural-5920, received more ground clearance, an improved track drive and a stronger frame. The petrol engine gave way to the KamAZ-740 V8 diesel with 154 kW (210 hp).

The plans were ambitious. The state plan for 1976–1980 called for about 8,000 tracked carriers. Reality was different: the first pilot batches left the plant only in 1983, because the plant was fully loaded with the Ural-4320 and the Ural-5557, which were in high demand. Small-series production began in 1985, with no more than about 150 units a year. The carrier was assembled at fixed stations rather than on a moving line, which made it expensive, and the plant sold it at a loss. Production ended in 1989.

Second life from 2003

Interest in the carrier returned with new investment in oil, gas and logging. In 2003 production resumed at a specialised-vehicle plant of the Ural group. The modern version uses the YaMZ-238M2 V8 diesel with 177 kW (240 hp), a hydraulic steering system and rubber-metal tracks with a longer service life. Its payload rose to 10 tonnes without increasing ground pressure, which stays at about 0.22 kgf/cm² at a gross weight of 24.5 tonnes. The plant offers bonneted and cab-over versions with flatbeds, rescue and fire bodies and a loader crane, and it builds carriers to order.

Engine, drivetrain and running gear

Both track bogies are driven. A symmetrical differential splits torque between them, and limited-slip worm-gear differentials in the drive units help in deep mud. Torsion-bar suspension gives a smooth ride for a tracked vehicle. The road wheels are of car type, but instead of air they are filled with a sponge-like mass, so they cannot be punctured. The track links have reinforced metal parts for strength and low wear.

By our calculation, the original carrier offers about 6.8 kW per tonne at full weight, and the 2003 version about 7.2 kW per tonne. Both figures are modest, but on a soft surface low ground pressure matters more than power. The power-to-weight calculator gives the same figure for other loads.

Checking a used Ural-5920

Most surviving carriers have worked for years far from workshops, so condition varies widely. A short inspection plan:

Spare parts for the engine, cab and transfer case come from the Ural and KamAZ truck families, while track parts are specific to the carrier and harder to find.