KrAZ-256: the twelve-tonne quarry dump truck from Kremenchuk

The KrAZ-256 was a heavy quarry dump truck of 12 tonnes, built by the Kremenchuk automobile plant. It replaced the KrAZ-222 and the YaAZ-210E, and in its 256B and 256B1 forms it became one of the most common machines in Soviet quarries and on large construction sites.

KrAZ-256 at a glance

The article is based on the Russian Wikipedia page on the KrAZ-256B; the English Wikipedia page on the plant supplies the model’s place in the range.

History of the KrAZ-256

Development of a new dump truck to replace the KrAZ-222 «Dnepr» began in the early 1960s and took about two years. Specialists from the Minsk automobile plant took part in the chassis work, and the KrAZ-256 shared its steering gear, springs and part of its electrical equipment with the MAZ-500 range. For the design the plant received a second-degree diploma from the VDNKh exhibition, and the truck won a gold medal at the international fair in Plovdiv.

The KrAZ-256B was exported to more than 30 countries. Machines sold between 1971 and 1979 through Avtoexport to the British company UMO Plant were then resold in Britain under the name BelAZ-256. In 1974 the dump truck received the State Quality Mark of the USSR. In 1977 the trucks were fitted with a new two-circuit brake system, and the resulting version was designated KrAZ-256B1. By the start of 1975 the electrical equipment of the 256B was 71% unified with other Soviet lorries, and the plant set itself the aim of reaching 75%.

The design was steadily improved. Service life before the first major overhaul rose from 100,000 km for trucks built before 1970 to 150,000 km for those of 1970–1976 and 160,000 km for those of 1977–1982; by 1985 the 256B1 had reached 165,000 km. In 1983 the NAMI test ground and KrAZ studied ways to cut the metal content, and in 1984 a bent-profile subframe reduced the weight of the frame by 115 kg. A version with a lighter body, for cargo with a density below 2 t/m³, was developed in the same year. Serial production ended at the end of 1993, with 4,928 dump trucks built in that year; the last 256B1S was made in January 1994.

Cuban operators kept the type alive: in October 2008 the Cuban ministry of construction and AvtoKrAZ set up a joint venture to repair and modernise KrAZ trucks, and in January 2009 the KrAZ-SOMEC plant opened in Cienfuegos with a capacity of up to 200 vehicles a year. More than 300 machines had been modernised there by 28 August 2014.

Design and features

• Rear-tipping scoop body: 4440 × 2430 mm, raised by two hydraulic cylinders through a lever-and-balance system.
• Two-circuit brakes: introduced in 1977 with the 256B1, one circuit for the front and middle axles and one for the rear axle.
• Heavy-duty chassis: five-speed gearbox and a two-speed transfer case with a lockable inter-axle differential.
• Export success: more than 30 countries, including a batch resold in Britain as the BelAZ-256.

KrAZ-256 versions

• KrAZ-256: the first model, a 12-tonne dump truck with a 215 hp engine, built from the first half of the 1960s.
• KrAZ-256B: 240 hp engine, built from 1966 to 1977.
• KrAZ-256B1: the 1977 version with a two-circuit brake system.
• KrAZ-E256BS: an experimental version for the Far North, developed in early 1967, with three machines built that year.

The 256 was one of the three models of the KrAZ-257 family, together with the KrAZ-258 tractor, and it was replaced in production by the KrAZ-6510. More trucks are in the KrAZ collection.

Video: KrAZ-256B1 old soviet dump truck

Video on YouTube.

Sources

• КрАЗ-256Б, Russian Wikipedia: history, design, production, modernisation
• KrAZ, English Wikipedia: place of the model in the plant’s range