Is there Warthunder Bias For Soviet Tech Tree

Nope! Soviet bias was merely just a funny joke that spread out as a meme. Then some ignorant guys interpreted it wrongly and made it a "truth".

Tier 5 is class of its own, here we MAYBE have some kind of Bias- but in a different way, I will explain later.

If we skip Tier 1 and start with Tier 2, I have only 2 kind of vehicles I have problems with. First is the GAZ MM. This is a normal truck with an automatic cannon on it. It cannot fire at targets on the grounds which are in front of them; also it has, more or less, no armour. But it is fast. In battles where you have to take flags these things will be there first- or, some very smart players, they just place themselves there, waiting for the Cromwells and other fast tanks in this class to come to take them out. The GAZ cannon is able to take out every tank in this Tier, some even full frontal. On the other side: you can take out a GAZ with your cal.30. Also, they don’t like artillery very much, so we cannot really speak about BIAS in this case.
The other tank is the KV-1. It is a heavy tank, it is hard to penetrate, but you can easily outmanoeuvre it with, for example, a Cromwell.

Conclusion: no Russian Bias in Tier 2

In Tier 3, fighting against Russians, means: I have a horde of M18s, some Fireflys and some Shermans against 16 T-34-xx (or, mostly, 8 T-34s and 8 Tiger Tanks). The T-34 is a very good tank, but it also has its weak spots. The earlier versions can be taken out full frontal with some luck, from the side I usually oneshot them by placing a round right between and above the second and third wheel, no matter if you are taking a US 75mm, 76mm or a 17pounder. On the other hand, the Russian cannon is strong as well. I guess, my win/loss ratio against Russians in this class is 50:50.
One quote on the KV-2: the Russians put a ship cannon onto a tank. This is no Bias, this was reality.

Conclusion: no Russian Bias in Tier 3

In Tier 4 we will see some very good Russian tanks: the IS-2, the T-34-100, T-44 and maybe even an IS-3 (my highest BR in Tier 4 is usually 6,3, which prevents me of facing some tanks I don’t wanna see in a match). Depending on the map and the kind of game I usually start with a fast tank or tank destroyer, like the Walker Bulldog or the Super Hellcat. The Bulldog was a very good tank, but sadly, Gaijin nerfed it to dead, so it lost his best advantages. If I take out the Bulldog, I am usually the first on a flag, able to take it. If I am able to place some hits, I will be the first tank in game that gets knocked out- but then I come back in a plane, usually in a Skyraider or a Wyvern, and take out between 1 to 3 Russian tanks. If not, most of the time I have to take an AA. The M19 or the Crusader AA. Both are able to take out Light and Medium tanks of the Russians from the side as well.
In this class I also play with the Pershing. I really like this tank, but compared to the Russian tanks in the same class it is weak, also very slow. But if you take the advantages of your tanks, especially US tanks (speed), you will have an equal stage of development.

Conclusion: no Russian Bias in Tier 4

Finally we come to Tier 5. I am really not good in this class, so I play it very rarely. I think, the British tanks are outclassed in this Tier, the don’t have APFSDS/APDS- I don’t know the correct description right now. But we have the M47, M48, 2 versions of the M60 and- the M551. And for me, the M551 is the only thing I can speak about a Russian Bias. Because: they have the IT-1. This tank is based on the T-62, which means: it is a tank. With armour. The M551 is not a direct opponent of this tank, this would be the M60A2. But Gaijin did not take it, but the M551 which has no armour at all, also a very high reload rate. Since they released the IT-1, I usually get knocked out by this tank, no matter where I am on the map. I was still able to take out a T-10 with a Falcon, but I was not able to take out the IT-1 from the side with this AA.

Conclusion: maybe a small Bias in Tier 5 due to a lack of comparable tanks. Maybe the future will change something, then there will not be any Bias anymore in this game.

And one final quote: I have more problems with German tanks recently. Is there maybe a German Bias in War Thunder?
PS: Some weeks ago I played a round on the Russian side. I was able to take out 8 enemy tanks and survived the round without a loss. There were many 'Russian Bias' comments in the chat, along with camper, cheater and so on. Ok, I agree, I camped (6 of these 8 tanks were on their way to a baserape-festival). But depending on Bias: I was in a Premium Tank, an M4A2 (76)W. This tank has no difference to its US brother. US Bias in War Thunder?