The variety of armored vehicles to Ukraine is increasing every day, and these are not only Leopard 2 or Abrams, but also Polish PT-91 Twardy. The French Leclerc and even the Challenger 1 are on the "horizon", as well as the Leopard 1, which Rheinmetall occasionally mentions.
Thus, the more tank names appear, the bigger the question is the size of the "zoo": a situation where instead of a single model, the army has a variety of non-unified but identical weapons, which puts a huge burden on logistics and support.
To assess this situation, let’s go back to the beginning of 2022 and see which tanks had already been in service at that time:
T-64BV, T-64BV model of 2017, T-64BV model of 2022;
T-72B and T-72AV;
T-80B and T-80BV;
BM Oplot (even in a rather small amount);
That is, already a dozen tanks that had their own differences. Of them, the T-64BV has a different engine than the T-64BM Bulat, and the latter is different from the T-64BM2, which was unified with the T-84, but not with the T-80. There is also a difference in the engines between the T-72 and the T- 72AMT. Sights and fire control systems are also not the same. Also the Oplot, which is in service with the Armed Forces of Ukraine and it would be unfair not to mention it. Also, for the sake of simplicity, let’s not go into detail mentioning the T-64B1V, T-64BM1 and T-64B1M (these are different vehicles), and even more so the T-64BVK commanding vehicles.
So, now it is worth adding to this list the russian trophy tanks. And the list includes T-72B3, T-80B, T-80U, T-80UD, single ones like T-80UE-1, T-80BVM, T-90A, T-90S, T-90M, T-62 and T-62M. That is, there are more than a dozen models and versions, where even the T-80BVM goes with different trims, for example, in terms of sights.
Next, the help of allies, consisting of the T-72 tanks of the Warsaw Pact countries, which are also slightly different from the Soviet T-72M. Some of them were also modernized after overhaul, like the T-72M1R, or are their own deep modernization the PT-91 Twardy. Also, the M-55S that is a modernized T-55 with the NATO 105-mm barrel and other improvements.
That is, at the moment we are talking about approximately two dozen different versions of tanks. But after a positive solution to the issue with Western machines, the Armed Forces of Ukraine are waiting for the Leopard 2A6 and Leopard 2A4, while the difference between these vehicles is more than significant, both in terms of armor, sighting devices, barrels, and more. We might add another probable tank, which is the Swedish version of the Leopard 2A5, namely the Strv 122.
Add the Challenger 2 and the already announced Abrams M1A2, and we will get six more versions, and in total from 25 to 30 tanks of various versions right now and in the short term of entering the service of the Armed Forces of Ukraine. And this might be the world record for versions of tanks in the ranks of one army.
Of them, all T-64, T-72, T-80, T-84, T-90, PT-91, as well as the Oplot have the same ammunition, but about 6-7 different engines or their versions. The T-62, M-55S and Challenger 2 each have their own separate ammunition. The Leopard 2 and Abrams are unified in terms of ammo, but not only have all other components different, they even require different sets of tools in the metric and inch systems. Challenger 2 needs both sets, because the turret and the body are on different "bolts".
And almost half of the "zoo" already existed in Ukraine as of 2021, and 3/4 of the list by the end of 2022, however such a situation isn’t problem-free. Ukraine is not in a position with freedom of choice which tanks the allies should hand over, since the weapons are needed here and now.
Moreover, even the NATO countries that are close to the russian border are taking the similar steps. For example, Poland in the short term will have T-72M (if not all transferred to Ukraine), PT-91 Twardy, Leopard 2A4, Leopard 2A5, Leopard 2PL, Abrams M1A1 FEP, Abrams M1A2 SEPv3, as well as Korean K2. That is, eight versions of tanks and this in peacetime conditions.
P.S. Below is the entire approximate list of available, announced and possible candidates for strengthening the tank fleet of the Armed Forces of Ukraine:
T-64BV model of 2017;
T-64BV model of 2022;
T-72B3 model of 2013;
T-72B3 2016 model;
----- Ukraine is currently somewhere here in this part of the list, the following are announced, but not yet transferred:
----- Unannounced but hypothetical candidates: