T.P.V. test report at La Ferté, 4 November 1948

In this document

The three cars and the participants

The report describes a comparative test conducted at La Ferté on 4 November 1948, between three vehicles: the A.6 series car, the L car (with single spring) and the A 11 bis (with rubber interaction suspension) p. 69. Present were Messrs. Pompon, Cadiou, Lefebvre, Magès, Lavoix and Renault p. 69.

Variable load tests

A first series of tests was conducted with two people and 50 kg of luggage: the A6 "has shocks in the floor", the L car shows "greater pumping [...] and less damping", while the A 11 bis has "almost zero pumping" but proves to be "a bit harsh" p. 69.

With four people and 50 kg, the A6 is judged "less good", harsher; the L car retains its qualities with fewer shocks, but "a little more damping would be desirable"; the A 11 bis remains "just as harsh", with few vibrations and few shocks p. 69.

Comfort in the rear seats is also noted: Mr. Lavoix's car (L car) offers comfort "better than A.6", while the A 11 bis is "harsher and worse than A.6" p. 69.

Finally, empty ("alone on board", with spare wheel and tools, without the 50 kg), the A6 and the L generally retain their qualities, Lavoix's car pumping less and approaching the A6; the A 11 bis shows more pumping than in the previous tests, but less than the A6 and the L p. 70.

Height and weight measurements

A control table (2 people + 50 kg of luggage) gives, in mm and kg, left (G) and right (D) sides:

p. 70

Context

These November 1948 tests are part of the development programme for the T.P.V. (Toute Petite Voiture), a project that would later lead to the Citroën 2 CV. The confrontation between different suspension principles — classic spring, single spring, rubber interaction — reflects the research conducted at that time within the design office to find the best compromise between comfort and road holding. These tests took place after the establishment of the plans for hydropneumatic suspension with differential interaction on 17 February 1944 (Hydropneumatic suspension plans with differential interaction (17 February 1944)) and preceded the first tests of the 2 CV with hydropneumatic suspension in May-July 1946 (Notebook of the first 2 CV hydropneumatic suspension tests (May-July 1946)) — research that Paul Magès would then lead until the hydropneumatic suspension applied to the future DS.

Archivist's perspective

This document concretely illustrates a phase of comparative tests, with the direct presence of Magès in the field p. 69, alongside engineers and managers from the design office. It testifies to a stage of arbitration between several suspension technologies for the T.P.V., in the period separating the hydropneumatic suspension plans of 1944 and the 2 CV tests of 1946, before the final choices were made.

The rigour of the recorded measurements (heights, weights, per side) shows the concern to objectively quantify driving impressions that were otherwise qualitative ("harsh", "pumping"). This document is part of the same collection as other items relating to suspension research from this period, such as the theoretical study folder on hydropneumatic interaction suspension 1943/44, which sheds light on previous research that may have informed these comparisons.