Wednesday 24 April 2019

T-34 with Torsion Bars

"Decree #___
Committee of Defense of the USSR
Moscow, Kremlin

On the transition to T-34 tanks with a torsion bar suspension

Instruct the USSR NKSM (factory #183) to produce two experimental T-34 tanks by April 1st, 1941, with the following changes:
  1. Replace the spring suspension of the T-34 with an individual torsion bar suspension.
  2. Install wheels with internal shock absorption.
  3. Widen the turret ring to 1600 mm, protecting it from jamming and splash.
  4. The crew must consist of 5 men, 3 in the turret (commander, gunner, loader) and two in the front hull (driver, radio operator).
  5. The top speed must be 65-70 kph.
  6. Install a V-5 600 hp engine (modernized V-2-K).
  7. Other tactical-technical characteristics of the T-34 remain in accordance with KO decree #428 dated November 19th, 1940.
  8. Perform factory trials by April 1st, 1941. Present the tank to the NKO for trials by May 1st, 1941.
    Order the NKSM and NKO to present its findings to the KO on the feasibility of producing the improved T-34 tank by July 1st, 1941.
    Order the NKS (Mariupol Factory) to produce two armoured hulls and turrets according to factory #183 blueprints by February 1st, 1941.
Chair of the Committee of Defense within the Council of Commissars of the USSR, Voroshilov
Secretary of the Committee of Defense within the Council of Commissars of the USSR, M. Pugayev

Approved: January 17th, 1941"


  1. Did they even produce a mock up or even just a few modified T-34s with torsion bars in 1941? I imagine they could of cut down some bars used in KV-1s and installed them in a T-34 hull and ran it without a turret.

    1. There was a re-equipping of a T-28 with torsion bars as a proof of concept, the same thing was never done for the T-34. I think they already had confidence in the concept. A T-34M prototype was being built when the war broke out, individual armour components were already produced and tested for toughness.

    2. I believe Kv-1 torsion bars didnt go across the entire hull but doubled half the way. Perhaps no modification was needed and technology was available. Choice was made to use what they already have in production as benefits didnt justify changing production process and developing new lines in factories and retraining of workers in critical time of need. Once they could afford necessary time they didnt just convert t-34 to accommodate torsion bar suspension, they built entire new hull and new tank t-44. That was such a great success and was used in t-54 and t-55 tanks.

    3. You're thinking of the Panther. The KV-1 had conventional torsion bars that ran the entire way across the hull. You can see the opposite side torsion bar in this diagram of the suspension:

      Drawing of opposite road wheels from the British report:

    4. Wasnt the Panther even worse with the Torsion bars running across the entire width of the tank AND back?
      The only tank that comes to mind with half width torsion bars I think is the Obj 268, though thats solely observation based on the WoT model back when I still played that.

  2. With reference to the T-28 proof of concept you mention Peter. Are these the same vehicles referred to as T-29s with various return roller arrangements?

    1. The T-29 was the T-28 with Christie suspension, totally different concept. Easiest way to distinguish is by road wheel size as the torsion bars have KV-esque road wheel and T-29 has the very typically large Christie road wheels.

    2. Thank You! I've found a couple of bits about the KV road wheel type now. It makes sense that KV parts would be used when the T-29 used BT/T-34 wheels.