Eleve az obj 167ből indult az obj 172 fejlesztése, aminek a modern páncélelrendezéssel szerelt változata obj 172M lett. De néha nem ártana elkezdeni azon gondolkodni, hogy hogy nézett ki a szovjet ipar felépítése.
In 1967, the Uralvagonzavod formed "Section 520", which was to prepare the serial production of the T-64 for 1970.[22] Because of the time-consuming construction of the 5TDF engines, which took about twice as long as the contemporary V-45, the Malyshev Factory in Kharkiv could not provide a sufficient number of 5TDF engines for all Soviet tank factories.[23] The Military-Industrial Commission (VPK) authorized work on two alternative engines for a wartime T-64, a so-called "mobilization model" that could be produced more quickly and at half the cost.[14] Obj. 219 (which became the T-80, with a GTD-1000T gas-turbine) was designed in Leningrad. Ob. 439 with a diesel V-45 engine was designed by Uralvagon KB at Uralvagonzavod in Nizhny Tagil.[24]
GABTU sent a T-64A prototype with a team to Uralvagonzavod. Kartsev was to lead this team.[25]
Kartsev was unsatisfied with the innovations of the T-64, and began instead a more comprehensive project to redesign the tank. Kartsev melded what he believed were the best aspects of the T-64A, Object 167, and an upgunned T-62.[25]
During development the tank was code-named "Ural" after the Ural mountain region.[14] Uralvagonzavod produced the first prototype with a T-62 turret, D-81 125-mm gun and V-45 engine in January 1968. Ob. 439 differed so greatly from the T-64 that it was redesignated as "Object 172".[24]
Kartsev's defiance angered GABTU, which initially reprimanded him for his insubordination. However, after the tank proved indeed to possess potential as a less costly alternative to the T-64, Kartsev was allowed to continue work on his design. Politically motivated opposition continued to beset the tank throughout its development. Vagonka tank plant manager I.F. Krutyakov sought to subordinate Uralvagonzavod under Josef Kotin. Kartsev skillfully beat back this play for power, embarrassing Krutyakov in the process. Kartsev retired in August 1969, and was succeeded by Venediktov.[25]
The team soon found out that the more powerful V-45 engine put a lot of stress on the T-64 hull, so that after some time cracks started to materialize. A more stable solution was sought.[23]
Finally, an idea from 1960 was used, when a modification of the T-62 had been discussed: In 1961, two prototypes of "Object 167" had been built by Uralvagonzavod to test a stronger hull and running gear combination for that tank. Under influence from Kharkiv, the idea had been turned down by Moscow.[26] But this construction, with its big, rubbercoated roadwheels now formed the basis for the mobilisation model of the T-64.[27]
Additional changes were made to the automatic loading system, which also was taken from an earlier project, originally intended for a T-62 upgrade. The 125 mm ammunition, consisting of a separate projectile and a propellant charge, was now stored horizontally on two levels, not vertically on one level as in the T-64.[28] It was said to be more reliable than the T-64 autoloader.[27] In 1964, two 125-mm guns of the D-81 type had been used to evaluate their installation in to the T-62, so the Ural plant was ready to adopt the 125 mm calibre for the T-64A as well.[29]
Venediktov's team later replaced the T-64-style suspension with the Obj. 167's suspension. The tank was trialed in Kubinka in 1968, and Central Asia in 1969.[14] After intensive comparative testing with the T-64A, Object 172 was re-engineered in 1970 to deal with some minor problems.[30] Further trials took place in Transbaikal in 1971.[14]
Ustyantsev, Sergej Viktorovich; Kolmakov, Dmitrij Gennadevich (2004), Boyeviye mashiny Uralvagonzavoda. Tank T-72 (Combat vehicles of Uralvagonzavod. T-72 tank), ISBN 5-98485-003-6
Suvorov, Sergey (1993), ТАНК Т-72 ВЧЕРА, СЕГОДНЯ, ЗАВТРА (Tank T-72 Yesterday, Today, Tomorrow), ТанкоМастер