Specification Crew : 4 Engine power : 500 hp Combat weight : 29,200 kg (64,386 lb) Max speed : road 47 km/h (29.19 mph) Range : 400 km (248.40 miles) Length : 8.15 m (26.74 ft) Width : 3 M (9.84 ft) Height : 2.45 m (8.04 ft) Main gun : 85 mm (3.35 in) Armour : 20 mm (0.79 in) to 45 mm (3.78 in)

Whereas the SU-122 had been designed as a multi-purpose assault gun the SU-85 was intended to be a dedicated tank destroyer.Design work commenced in August 1943 and was considerably assisted by the experience gained during the development of the SU-122.The armored superstructure of the SU-85 was virtually identical to that of the SU-122.However the SU-85's 85 mm (3.35 in) gun based on an anti aircraft gun was mounted in an armored ball mantlet also employed by late production SU-122s. By August 1944 the first 100 SU-85s were ready to enter service with the Red Army's newly-formed tank destroyer battalions.Like the German Panzerjager the SU-85 was handicapped by the limited traverse of its main armament.If a target moved outside it's field of fire the SU-85 often had to manoeuvre to engage it.Once involved in a mobile battle a tank with a fully traversable turret had the advantage.More difficult to explain the SU-85 lacked a machine gun making it vulnerable to enemy infantry with anti-tank weapons , a danger countered by SU-85s standing well back from their targets and engaging them at long ranges.The introduction of the T-34/85 medium tank with the same armament made the SU-85 obsolete.By early 1945 they had been withdrawn by the Red Army and replaced by the SU-100.Surviving SU-85s were handed ot to the armies of the Soviet satellite states in eastern Europe.