No offense but you need a much better source than this Statista graph.
TLDR: the USSR produced about 2800 tanks in 1940 and 6690 in 1941, so the numbers don't look anything like this graph and the Soviet Union had been manufacturing tanks at scale since the early 30s.
Soviet combat vehicle production during World War II - Wikipedia
Light armoured fighting vehicles
- 1940 2,422 (1601 T26)
- 1941 2,321 (1388 T60)
Medium armoured fighting vehicles
- 1940 128 (T34 mostly)
- 1941 3016 (T34 all)
Heavy armoured fighting vehicles
- 1940 243 (KV1, KV2)
- 1941 1353 (1121 KV1)
Remember, in 1941, at the start of Barbarossa, Russia has a huge advantage in tank numbers, 11000 to 3800.
They did not get produced in 2 years and Khalkin Gol - 1939 - went badly for the Japanese in no small part due to Soviet tanks. Indeed look at the T26, its most numerous tank.
Produced 1931–41
No. built 10,300 tanks
Tanks of the Soviet Union - Wikipedia has some general background on them, if not exact year by year numbers. One really doesn't have the impression there was a lull in 39 40.
In 1926, under a secret annex to the Treaty of Rapallo, the Soviet Union and Germany set up a joint tank school at Kazan in the west of the Urals, which was illegal under the Treaty of Versailles. Both countries learned much about tank design and tactics in this co-operative venture.
Based on a mixed force of foreign tanks and imported prototypes, the Soviets developed a large domestic design and production capability. The T-26 light tank was based on the Vickers E (as were many other tanks of the period), chosen after it beat a Soviet FT derivative in trials.
Kliment Voroshilov ordered the creation of the "Special Commission for the Red Army (RKKA) new tanks" under the direction of S. Ginzburg to define the tank type suitable for the Red Army. ... On 13 February 1931, the Vickers 6-Ton light infantry tank, under the designator T-26, officially entered service in the Red Army as the "main tank for close support of combined arms units and tank units of High Command reserve".
While things look pretty amateurish in 1941, let's not forget that Tukhachevsky developed the Deep Battle concept in the mid 30s and seems to have been every bit, if not more, forward-thinking as his peers like Guderian, Liddell Hart, DeGaulle... The USSR is not inventing tank doctrine or manufacture in 1940+, it has been doing both for a long time (which is how it had 11000 tanks at the start of Barbarossa), it just happened to have purged its military theorists ;-)
Order of battle start of Barbarossa
Even though tanks like the BT7 and T26 get dissed compared to the T34s and KV1s, the comparison is less disfavorable when compared to German tanks, which generally weren't much to write home about in 1941. The T34 comes as a complete surprise to the Germans and far outclasses anything the Germans field, on paper. In practice it had some flaws, but was still much better than its German counterparts (this concerns 1941 and tanks evolve very quickly in 1942+ on the German side, if not always in optimal fashion either).
Germany enjoys early success in armored warfare against the USSR due to better doctrine, better leadership and Soviet deficiencies in leadership, logistics, stockpiles and auxiliary gear like radios. But certainly not through an absence of theoretically-competitive Soviet tanks.
Come back with some other sources and maybe there is a basis to look at those numbers more in detail. But as it is, this question, is starting from what's most likely a massive mistake by a company that's more specialized in modern data.
Re. tooling for tanks in 1941, the "big event" that dominates everything is having to move production lines to the east of the Urals, after losing so much ground in Western Russia. So a detailed month by month look at 1941-42 would probably see a dip or at least flatline for parts of it, before a strong rebound as the relocated factories come back online.
IIRC there was also a massive rationalization, as everything shifted to T34s, KV1s and T60s: the Russians very quickly aimed for maximizing the numbers of their latest and dropping the older stuff. Later on lighter tanks like the T60s and T70s would lose some of their emphasis and they would start experimenting with stuff built on common chassis like the SU-76.
Soviet combat vehicle production during World War II - Wikipedia
Interestingly, the near-flatline numbers for 1940 make more sense, if they are understood to mean medium or heavy tanks: Soviet numbers there are very low: 100s and 200s. The action is in the light tanks: 2422 produced in 1940. That's not that unusual: WW2 started out with a number of countries fielding very light tanks that were pretty quickly recognized to be obsolete.
Chelyabinsk Tractor Plant/Tankograd is an interesting snapshot of one plant's evolution.
Already located safely in the east, it does not produce tanks at the start of the war, but retools quickly from tractors to tanks:
The Chelyabinsk Tractor plant was a project of the first five-year plan.[6] The plant was founded in 1933; the first product was a 60 hp tracked tractor C-60 (Сталинец-60, Stalinets-60) fueled by petroleum ether (Benzine). In 1937 the factory produced its first diesel-powered vehicle C-65 (Сталинец-65, Stalinets-65). By 1940 the plant had produced 100,000 tractors.2
During World War II seven other industrial entities (including most of Leningrad's Kirov Plant and 15,000 of its workers[7]) were either wholly or partially relocated to Chelyabinsk, the resulting enterprise commonly known as "Танкоград" ('Tankograd', or 'Tank City').[note 1] The work force increased to 60,000 workers by 1944, from 25,000 during non-military production; during the conflict the works produced 18,000 tanks, and 48,500 tank diesel engines as well as over 17 million units of ammunition. Production included the KV tank from 1941, T-34 tank from 1942, KV-85 tank and IS tanks from 1943, and T-34/85 tank and SU-85 self-propelled field gun from 1944[1][8][9] By 1945 the plant had been awarded the Order of Kutuzov, 1st Class, the Order of Lenin, the Order of the Red Star, and other honours for its efforts in helping to defeat Nazi Germany.2
