How good is the TR 85-M1 tank?

There is no credible source that mentions this theory with the Type 80 as the origin of the TR-85. The tank has a number of parts with Chinese origins, but overall it is certainly not a collaboration with China.

Mircea87, you also can be right in terms of Romanian-Chinese cooperation in the production of the TR-580 and TR-800 tanks. As I said the source cited by me is questionable (he says that he was a military engineer and worked in the 23 August factories in Bucharest) in in the sense that the Romanian-Chinese cooperation could materialize only on some components of the tank f.i. (making his statement to be true) and maybe even after the production started. I believe his claim because I saw many similarities between our TR-580 and the chinese Type-80. However I must admit that there are some temporal inconsistencies since our tank appeared in 1977 and the Chinese only after 1980... But still I do not exclude the idea of ​​a collaboration in the design of tanks between Romania and China, without this necessarily lead to a joint execution of TR-580 tank.

TR-580 is a licensed built T-55. The chassis was extended in order to accommodate a larger Leopard 1 engine. West Germany refused to give the license for the engine and, as such, the tank used the initial extended chassis and the V-2 engine of the T-55 (which, by some sources, was of Polish origin until we were able to produce it locally). The government decided to use the extended chassis anyway because it could later retrofit it.

Ok Mircea87, I can believe that!
Once I don't have solid evidence (documents or testimonies) of the jointly construction or cooperation of our tank with China, it's very possible that you told the truth! Or why not that the chinese inspired themselves from our design?
But back to the subject "How good is the TR 85-M1 tank?", I think that is an acceptable tank who missed the chance to be even a good tank! I repeat what was already said in this topic, namely that an ERA add-on armor on the turret and on the front and side of the chassis and also a 125mm A555 smoothbore main gun planned for TR-125 could make him a strong competitive tank! It isn't fair to compare him with the newest ukrainean T-55AGM tank, as long as the ukrainian tank appeared only few years ago, but I am sure that this T-55AGM is better than ours. It's questionable if the Russian tank T-55M5 or the slovene T-55S1 (M-55S1) are better or not but the fact is our tank could be better. The good thing is however that the romanian BM-412M cartidge for the 100mm gun can penetrate 418mm of armor at 2000m and 380mm of armor at 3000m. That means that in theory the T-72, T-72M or T-64A (all of them without ERA) armor can be pierced by a frontal shot. My question is : what about T-64BV (transnistrian and ukraineans have it!) or the better T-64BM Bulat not to talk about the T-80BV/-80U or UD or the newer T-84/Oplot and Oplot-M? I agree that in the 1992 war in Transnistria some russian/transnistrean T-64BV were destroyed by the moldavian MT-12 "Rapira" AT guns (so our A407 100mm anti-tank gun M1977 can do the same) but what to do with the more advanced tanks...?

First of all, ERA armour is pretty expensive, it is sort of heavy for a tank which is already underpowered and is only useful against HEAT/HESH rounds and small anti-tank weapons. The penetrator rod of a sabot round could theoretically be deflected, but in practice it's rather hard to achieve such a result. For example, Kontakt 5 reduces APFSDS penetration only by about 20-35%. If you install a 125 mm gun in a tank with a prolonged hemispherical turret, you need to have an automatic loader or you'll have less than 20 rounds available. You also need to modify the recoil mechanism and you need to balance the heavy weight of the gun. These changes would result in a rather obscene price for the TR-85M1, which is already expensive for the age of the design and actual capabilities.

The Russian conducted a number of tests in the 1980s with an Israeli 105mm M111 APFSDS. They found out that it could penetrate the glacis armour of T-72s and early T-80s. That's why they installed 20mm add-on armour on the T-80B. After 1990, the US Army conducted a number of tests with T-80U and T-72B. Their 120 mm ammo had difficulty penetrating the armour of these tanks. The TR-85M1 is likely unable to penetrate the frontal armour of the late models T-80, while it its own frontal armour can easily be penetrated by using advanced 125 mm ammo. From the side, both tanks can destroy each other, no doubt about it.

TR-85M1 could probably penetrate the frontal armour of the T-64BV, especially in the hull glacis:

Israeli M111 Hetz AP stats: 310mm at 2km (150 mm for armour at 60°)
Romanian/Israeli M309 AP stats: 418mm at 2 km

The turret glacis is rather hard to penetrate for both T-64BV and Bulat. The question of how good is the TR-85M1 vs T-64s is irrelevant since there are over 2000 T-64 tanks in service in Ukraine while RoArmy only has 54 TR-85M1 tanks. It will be overrun in a matter of days, by enemy fire or attrition rates.

Thanks Mircea for some new informations I didn't know (the soviet tests with israeli ammo)!
I read about the German army (Bundeswehr) tests after 1990 on East German T-72M and M1 tanks, but also on T-64B and T-80B (the last two don't know where they would have had?) after which they said their Leopard 2 tanks are far superior to any of the soviet ones (in terms of protection and firepower)! So for those who plead for the purchase of Leopard 2 tanks by the Romanian army the answer is YES! Do it! (if we can?!)
About the T-64BV tanks, I was first thinking at Transnistrians tanks (only 18!), not the Ukraineans, since I am one of those who say that any (military) conflict with Ukraine would have for as the same consequences as for Georgia the war with Russia...
Indeed the small number of TR-85M1 is decisive, so that any discussion about his combat value of is slightly useless...