KrAZ-250

KrAZ-250 at a glance

The KrAZ-250 was the plant's attempt to give its proven heavy truck a modern cab and a chassis ready for special equipment. German-language Wikipedia describes it as technically very close to the KrAZ-257, which stayed in production in parallel for the whole period. The main visible difference is the newer cab with a shorter bonnet. Electrics and brakes were revised, and a version with a wheelbase 80 cm longer was offered.

The plant's background is told in the history of KrAZ, and every model is listed in the KrAZ catalogue.

From early prototypes to series production

The idea of a new KrAZ heavy truck goes back to the early 1960s. The plant built two prototypes of a new truck at that time, together with a prototype fire engine on the same chassis. Series production took much longer to arrange. According to the old 1cars text, the main obstacle was the plant's dependence on outside suppliers for key components, so about two decades passed between the first design work and the start of production.

Production began in 1978. KrAZ designed the 250 as a unified vehicle: important parts were interchangeable with other Kremenchuk trucks and even with the MAZ-500 family, whose front axle it shared. The old 1cars text notes that the cab was modified three times during the production run. The truck worked mainly in mining, oil fields and construction, and it was rated for operation between −40 °C and +40 °C.

YaMZ-238M2 V8 diesel

The KrAZ-250 uses the YaMZ-238M2, a four-stroke V8 diesel with a displacement of 14.86 litres. German-language Wikipedia lists 177 kW (240 PS) and 883 Nm. The engine has an all-speed governor, an eight-section injection pump with a low-pressure feed pump, a fuel-injection advance coupling, a pre-start heater and a dry air filter with a clogging indicator. The old 1cars text adds that the 250 received a tubular-ribbon radiator in place of the earlier tubular-plate type.

Clutch, gearbox and transfer case

Power goes through a dry twin-plate clutch of the YaMZ-238 type with peripheral springs and a mechanical release. The YaMZ-236N five-speed manual gearbox has synchronisers on second to fifth gear. Behind it sits a two-speed transfer case with a lockable centre differential between the two rear axles. The transfer case is shifted mechanically, while the differential locks engage pneumatically. Three propeller shafts carry the drive to the rear axles.

Chassis, brakes and steering

The front axle hangs on semi-elliptic leaf springs with shock absorbers. At the rear, a balancer (bogie) suspension uses two semi-elliptic springs with sliding ends and reaction rods. Ground clearance is 270–275 mm, depending on the source.

The service brakes are dual-circuit and air-operated, with drum brakes on all six wheels. According to the old 1cars text, one circuit serves the front and intermediate axles and the other the rear axle. A mechanical transmission brake acts as the parking brake. An alcohol-type anti-freeze unit and a water separator stop condensate from freezing in the air system in hard frost. Steering is of the screw and ball-nut type with hydraulic power assistance.

Dimensions and weights

By our calculation, 177 kW at a gross weight of 24 tonnes gives about 7.4 kW per tonne. Compared with the later MAZ-5337 at 18 tonnes and 169 kW, about 9.4 kW per tonne, the KrAZ is slower to accelerate but carries far more. Other loads can be checked with the power-to-weight calculator.

Cab and equipment

The all-metal cab seats the driver and two passengers. The driver's seat adjusts for height and weight. Equipment included a heater, warm-air demisting for the windscreen, wipers, a fan, wind-down windows, swivelling vent windows and rear-view mirrors. The old 1cars text also mentions a radio, a document compartment and a sun visor. Warning lamps on the dashboard report high beam, low air pressure in the brake reservoirs, low oil level and engine overheating. The cab and front panels sit on the frame at four points.

Crane, mixer and tractor versions

Most KrAZ-250s left the plant as chassis for special equipment. Common bodies were truck cranes, hoists and concrete mixers; the flatbed truck with drop sides was rare. The list of KrAZ vehicles also names the KrAZ-250V tractor unit and two prototypes, the KrAZ-251 and KrAZ-252.

The best-known crane on the chassis was the KS-4562. According to the old 1cars text, it lifted up to 20 tonnes and had outriggers for stability. Its maximum hook height was 10.3 m, it could lower a load 4.4 m below ground level, and its reach ran from 3.5 to 12 m depending on the boom equipment. The relatively compact wheelbase let the crane work in tight construction sites.

Related KrAZ trucks and successors

In 1992 KrAZ replaced the 250 with two new families. The KrAZ-6510 tipper and the KrAZ-6443 tractor (with its 6x4 version, the KrAZ-64431) kept the same engine and wheelbase. The all-wheel-drive KrAZ-260 was the 6x6 counterpart of the 250 in the same period, and the older KrAZ-255 remains the plant's best-known off-road truck.

Owning a KrAZ-250 today

Surviving trucks are usually crane or mixer chassis that have done decades of site work, so condition matters more than the year. Before buying one, check these points:

• the air system: listen for leaks with the engine off and watch how fast the reservoirs fill;
• the YaMZ-238M2: cold start, smoke on load and oil pressure when warm;
• the transfer case and the pneumatic differential locks, which should engage and release cleanly;
• the frame around the crane or mixer mounting, where cracks and old weld repairs tend to appear;
• the steering box and power-steering pump, which take heavy loads on a slow-moving crane truck.

Parts for the engine, gearbox and axles are shared with many other trucks of the period, which keeps an old KrAZ-250 workable.