The vehicle was equipped with a new eight-cylinder, diesel-powered YaMZ-238 engine. Due to the versatile design of the KrAZ-255B, a wide variety of technical equipment was developed based on its chassis.
TECHNICAL DESCRIPTION:
The KrAZ-255B is an off-road/on-road truck featuring all-wheel drive, designed for transporting cargo and towing trailers across various road conditions.
The drivetrain includes a dry, dual-plate friction clutch with cylindrical pressure springs. The transmission features five forward gears and one reverse gear. Two inertia-type synchronizers ensure smooth shifting between the 2nd–3rd and 4th–5th gears. The transfer case consists of a two-stage auxiliary gearbox, the main transfer unit—which houses an inter-axle differential for distributing torque between the rear axles and the front axle—and a power take-off unit for driving the winch. The driveshaft system comprises five shafts and an intermediate bearing for the rear-axle drive. These are open, tubular-type driveshafts, with the universal joints (cross-joints) equipped with needle bearings. The middle and rear axles are identical in design; each features a two-stage final drive consisting of a pair of helical-toothed bevel gears and a pair of spur gears with straight teeth. The front-axle half-shafts are fitted with constant-velocity (homokinetic) joints. The axle tubes are press-fitted into the axle housings.
The frame is constructed from two channel-section side members connected by five crossmembers. Bumpers and towing equipment are located at the front and rear of the frame. A towing hitch is mounted on the rear crossmember, while the front features towing forks equipped with rubber shock absorbers. The vehicle’s front suspension is based on semi-elliptical leaf springs, with the ends of the springs seated in rubber cushions housed within the mounting brackets. The leaf springs operate in conjunction with two telescopic shock absorbers.
The rear suspension is of the swinging-arm type, utilizing two longitudinal semi-elliptical leaf springs, the ends of which rest freely on the cylindrical surfaces of special brackets. Propulsive forces, as well as the torque and reactions generated during braking, are transmitted via reaction rods. The vehicle is equipped with disc-less wheels featuring removable rim flanges. There are seven wheels in total: two at the front, four at the rear, and one spare. Wheel toe-in is measured relative to the front faces of the brake drums. The tires feature a wide profile, and their inflation pressure is managed by a central tire inflation system, with pressures ranging from 3.5 to 1.0 kg/cm2 depending on road conditions.
A winch is located in the central part of the vehicle, beneath the cargo bed. It features a horizontal drum and is equipped with a cable-laying mechanism (level-wind) with a winding limiter, a band brake, and various safety devices. The working length of the cable is 55 meters, with a diameter of 21 mm.
The cab is an enclosed, metal-and-wood structure with seating for three: an adjustable driver’s seat and a bench seat for two passengers. The cab is equipped with a heater, air vents, pneumatic windshield wipers, a blower that directs warm air onto the windshields, a cooling fan for the driver, rearview mirrors, a storage box, a document pocket, an ashtray, a fold-out sleeping bunk, and a sun visor. The dashboard features control instruments, including a speedometer, an ammeter, a fuel level gauge, a water temperature gauge, an engine oil pressure gauge, and gauges for air pressure in the braking system and tire pressure.
The cargo bed is made of metal and features an opening tailgate. In the front section of the floor, there is an access hatch for operating the winch. The cargo bed is equipped with removable openwork side extensions, folding side benches, bows for securing a canvas cover, protective flaps, and mounts for tools such as shovels and pickaxes. At the front of the cargo bed, there are sockets for positioning the bows when the canvas cover is removed.
Technical Specifications: 6×6 drive; payload capacity – 11,950 kg. Maximum towed trailer weight: 50 tonnes on hard-surfaced roads; 20 tonnes on unpaved roads or off-road. Overall dimensions: length – 8,645 mm; width – 2,750 mm; height to the top of the cab (unloaded) – 2,940 mm; height to the canvas cover (unloaded) – 3,170 mm; height to the cargo bed floor – 1,640 mm. Cargo bed (metal): length – 3,770 mm; width – 2,185 mm; height – 800 mm. Curb weight – 11,350 kg. Vehicle weight including equipment – 11,950 kg.
Engine: YaMZ-238, a four-stroke, V-type (90°), 8-cylinder diesel engine with a displacement of 14.86 L. Engine power: 240 hp at 2,100 rpm. Engine weight: 1385 kg; fuel tank capacity: 2 x 225 L; maximum speed: 70 km/h. Transmission: manual, five-speed plus reverse. All gears synchronized except for 1st. Gear ratios: 1st – 5.26, 2nd – 2.90, 3rd – 1.52, 4th – 1.00, 5th – 0.664, R – 5.48. Two-stage transfer case with ratios: H – 1.23, L – 2.28. Fording depth: 1 m; tire size: 1300x530x533. Wheelbase: 5300 mm; track width: 2160 mm. Ground clearance (loaded): 360 mm. Turning radius: 13 m; minimum external turning radius: 14 m. Central tire inflation system.
