Test report of 23 April 1958: friction of front suspension components (Dascotte)

In this document

This is the first page of a 5-page test report, titled "Mesures de frottement sur organes de suspension AV" (Friction measurements on front suspension components), carried out by the Dascotte establishment on 23 April 1958 on the car registered DS 8962 BX 78 p. 11.

Protocol

The document describes the necessary setup: removal of the front wings and cylinder protective plates, connection of two front cylinder supply tubes to a pump equipped with a pressure gauge, and placement of an index p. 11. The goal is to measure the pressure variation in the front cylinders required to obtain a displacement of the car, the latter being "substantially at the road position" p. 11.

Series of measurements

Four successive configurations are recorded, with a series of handwritten values and a calculated average for each:

The mention "après gymnastiquage de la voiture" p. 11 suggests a cycle of movements imposed on the vehicle before taking measurements again, without the document specifying the nature of this further.

The bottom of the page contains a standard Citroën administrative box (NAME/DATE/VISA columns, "LANCE PAR NOTE N°", "REMPLACE", "MODIF." mentions), which remained empty of visible entries.

Context

The DS, launched by Citroën in 1955, is equipped with the hydropneumatic suspension developed in particular by Paul Magès. This type of friction test on suspension components is part of the development and quality control campaigns conducted in the factory and at subcontractors or test service providers such as the Dascotte establishment, not identified more precisely here.

Measuring the friction of the cylinders and linkages (steering ball joints, shock absorbers) was a significant technical challenge to ensure the comfort and precision of handling sought by this suspension system, which is sensitive to the slightest parasitic resistance.

Archivist's view

This document is a raw technical piece, probably intended to support the development work on the DS front suspension carried out in Paul Magès' circle at the end of the 1950s. Its interest lies in the precision of the experimental protocol and in highlighting, by comparing the four series of measurements, the influence of the shock absorber and steering ball joints on the overall friction of the front axle p. 11.

It is likely part of the same test file as page 5 on wheels without front shock absorber and page 3 on trestles, roll links disconnected, both carried out on the same DS 8962 BX 78 vehicle, which suggests a methodical test campaign exploring several successive mechanical configurations.