Truck T14 KrAZ 255B 6x6 (Red) with instructions

Model "Truck T14" KrAZ 255B 6x6 is build with LEGO® in scale 1:17,5 and motorized using LEGO® Power Functions®. It is a model of a KrAZ 255B 6x6 off-road truck which is used for extreme applications. 

Update 1: instructions are available: Instructions are now available for you to build your own copy of this truck. This first release of the instructions will include the build of the basic model. See building instructions and inventory/parts list!.

Update 2: log truck conversion added: The already available instructions do now include the conversion to the log truck edition and the build of the stinger steered log trailer. 

The truck features: solid axle suspension on all axles of which the rear axles use a tandem bogie suspension, PF powered driving on all axles 6x6 drive, reduced speed to increase power/torque, Servo powered steering, fully functional fifth wheel, modeled V8 engine, detailed cabin interior and two light units.

Scale: 1:17,5
Length: 477 mm (+ trailer 926 mm)
Weight: 1,92kg (+ trailer 2,41kg)
Parts: 1840 (+ trailer 2270)

As a tribute to this truck this project shows some of the unlimited possibilities. Even though this specific truck was never produced as a civilian truck however after its retirement it has been used as such. Within a couple of minutes it can be changed into one of the four different editions which include:
- Semi-truck with fifth wheel
- Ballast tractor with ballast box
- Trial Truck edition
- Log Truck with stinger steered trailer
So it is up to you what kind of job it does: just having fun as it being a Trial Truck, or will you give it a semi-trailer? Or will it be hauling logs?


As one of the designer's trademarks this truck model is provided with full suspension. Regular LEGO® Technic shock absorbers proved too large. Installing those would have compromised the tractor's chassis realistic looks. Instead Rubber Belts are used as shock absorbers. To achieve this the movement is converted using a lever constructions. In the end a spring is pushed in and comes back, a Rubber Belt is stretched and comes back. This applies to the front axle only, the double rear axle setup is fitted with a tandem bogie suspension. The us of this setup allows easy axle and wheel travel.

Because it doesn't use any shock absorbing the wheels and axles do not have to deal with any force. It is based around the concept of the walking beam suspension. Both front and rear axles are fitted with "Technic Steering Wheel Hub with 2 Pin Holes". These hubs have proved to be a real improvement, less friction and the wheels do not bend under the weight of the model as it would without.

This KrAZ 255B 6x6 model is powered by a YaAZ-238A V8 4-stroke Diesel Engine which is visible with the hood opened. This power source has 8 cylinders in a V setup with a displacement of 14,87 liters. The initial YaMZ-238 delivered 215 hp with a torque of 785 at 1500 rpm. Since 1966 the YaAZ-238A engine was installed and delivered 240 hp with a torque of 883 at 1500 rpm. This detailed V8 engine is nice to build and to give it those realistic looks a total number of 80 parts is used. It is detailed with for example air filter, fan, fan belt, pulleys, hoses, by-pass oil filter and the exhaust system.

Together with much more engine bay details which are added the looks are phenomenal. These include break fluid reservoir, multiple reservoirs and details, radiator with tubing and steering shaft. By opening the cabin doors the interior becomes visible. It shows a steering wheel, basic gauge setup, a gear shift and another shift to engage high or low gear and finally some basic seats.

Semi-truck with fifth wheel
For a basic configuration a fifth wheel is mounted. Because of this a semi-trailer can be hooked up. Since this is a common application it makes the truck extremely versatile and depending on the used trailer it still suites any kind of terrain. At the rear end of the chassis has wedges installed to allow easy attaching of any semi-trailer. By adding a winch the versatility can even be increased. The battery box is simply sitting behind the cabin and the spare tire is mounted to the truck's roll bar.

Ballast tractor with ballast box
As used to haul extremely large and heavy loads this truck can be fitted with
a ballast box. What it basically does is adding weight to the rear axles to improve traction. While fifth wheel mounted trucks have there semi-trailer to add weight to the rear axles it is now replaced with a ballast box. The truck's battery box is inside this ballast box and acts as weight. If required more weight could easily be added by fitting a second battery box. A spare tire is mounted that fits the truck as well as four spare tires that would fit for example a drawbar lowboy trailer.

Trial Truck edition
To be used as just an off-road truck to fool around with a trail truck body
can be installed. To distribute the weight of the truck equally over all axles the battery box placed on top of the rear axles. Even though spare tires are not common for trail trucks two are installed to improve the looks of this truck. It is always impressive to see a truck with these large wheels having some spares. Mounted to the roll bar and easy to access when needed. To improve the off-road abilities the rear end of the chassis could be changed easily. In order to be able to change this truck to any given configuration the chassis is standard. Shortening the chassis would increase the departure angle of the truck. Also could the approach angle be increased as well by removing the front end's tow socket.

Log Truck with stinger steered trailer
Using this truck to transport logs requires to additions. The first one is a bolster mounted to the truck's chassis. It is sitting directly on top of both rear axles which enable good weight distribution. Second is the stinger steered trailer. Basically this trailer is a large tube with a tow ball at one end and a partial chassis with a bolster and two sets of wheels attached to it. The two sets of wheels are attached to solid axles which uses the same hubs as the truck does. Essentially the axle setup is equal to that of the truck without the drivetrain. Again it uses a tandem bogie suspension setup which allows easy axle and wheel travel.

To hook it up to the truck it has a tow ball which connect to the truck's tow
ball socket. The trailer's bolster is exactly the same of that of the truck and both are foldable. A optional chain across keeps the load secured. Finally the partial chassis with the axles and bolster attached is slidable. Allowing the full log combination to haul different lengths of logs. Both minimum and maximum reach are marked as is the centre location. The latter is used to be stored on top of the truck's bolster using a log loader for example. This is the most efficient way to transport the truck without any load.

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