The SU-85 tank destroyer is a derivative of the successful T-34 medium tank family and made its public appearance in August 1943. At that time, the powerful Panther and Tiger tanks had to be fought at distances that did not result in suicide for the Soviets. Then, it was decided to modify the 85mm D-5 anti-aircraft gun and turn it into the D-5T anti-tank gun, capable of facing the German giants with a chance of success at normal combat distances. The new gun was installed in a T-34 tank chassis, in a casemate mounting, which greatly limited the traverse of the gun. However, the vehicle had excellent mobility and a low height, ideal to ambush its prey. The SU-85 stopped being built when the new T-34/85 tanks entered service in late 1944. This tank had the same gun on a turret, and this allowed them to fire in any direction without having to maneuver the entire vehicle. This is why the SU-85 was no longer necessary and was replaced by the SU-100, with a new powerful 100mm gun. About 2,000 SU-85 were built and a some examples were exported to a few Eastern countries, Vietnam and North Korea.
SU-85 gallery and more info