21 NIII » I-103

21 NIII was the author of the first multi axial off-road chassis. In 1966, they developed a new 6-axle chassis using details of two I-21-15 prototypes. This was the scaled model (25% smaller than real one) of a 22-tonnes I-103 12x12 chassis with 3 front and 3 rear driven axles with the same track wide (2304 mm).

It was fitted with a naturally aspirated UTD-20 V6 diesel (15,9 liters, 300 hp) from a light tank. Other design elements were similar to the 4-axle prototypes. It had a Tatra-type tubular spine frame with an independent torsion suspension, manual gearbox and two single place cabins with external corrugated panels. Turning radius — 17.9 meters. Curb weight — 36 tonnes. Wheelbase between the front and the last axle — 9450 mm. Overall dimensions — 11,400x3025x2350 mm. Top speed — 70 kph.