Citroën rear suspension (1):
monogramme AMI6 Atlas

Original page created on 29/04/2023; last modified on 18/01/2024.

Rigid axles on cars with independent wheels: an aesthetic problem

At 1:87, model car manufacturers don’t bother to represent independent wheels. It’s true that, most of the time, it’s hardly noticeable. The exception to this is the small Citroëns, from the 2CV to the AMI8, which have a very high rear end, and whose very special suspension is particularly visible, even when the car is resting normally on the ground.

Wiking has put independent rear wheels, with varying degrees of success, on its Renault 4. Why not consider it for other models?

A little riddle

Citroën Atlas / Norev

Little riddle: What do these Citroën Atlas / Norev have in common? Well, they have rear wings without (or almost without) wheel arches.

As a consequence, the view from the rear is spoiled, especially for the Ami 6, by the axle that doesn’t exist in reality, and also by the rear track that is much too narrow, because of the too strong thickness of the casted metal wings. The rear track is roughly 2 mm too narrow. As the rear wheels are close together, the wheelbase seems to be reduced. Compare the AMI 6 Atlas with the real one…

As Wiking did with more or less success on their Renault 4, I wanted to give this Ami 6 a rear suspension with independent wheels, and to refine the wings to get a rear track more in line with the original.

Operations

Disassembling the chassis

To remove the chassis, you need to remove the front rivet: I use a ⌀ 2 spherical and a ⌀ 2.5 cylindrical mill bits.

Milling the rivet

Note: this picture was taken later, so the rear wings are already machined, which will be discussed next.

Separation of the rear axle

This separation is not easy, because the axle ends are knurled, and the wheels are tight on it. You have to pry with a small screwdriver between the wheel and the chassis to get it off.

Machining the body

The aim is to thin the rear wings down. This is done with a ⌀ 2.5 cylindrical milling bit, with care not to go through. We can easily remove 0.5 mm of material.

Left wing…

Machining the left wing

Click on the picture to see the machining.

… then right wing.

Machining the right wing

Then, drilling the old rivet to ⌀ 1.3 (max. depth 3.5) then tapping M 1.6 to replace the rivet by a screw.

Machining the chassis

Trim the axle passage that protrudes under the chassis (arrow). I should also have taken the opportunity to level the locking system on the base. That’s for later…

Levelling the axle passage

Click on the picture to see the machining.

Drill a ⌀ 1 hole about 3 mm deep on both sides at 3 mm in front of the old axle passage. The drill bit shows the location.

Drilling the suspension arm joint

Click on the picture to see the drilling location.

Making the suspension arms

These arms have a centre distance of 3 mm. I made them from 0.2 mm thick nickel silver. The 1 mm axles are soldered in the holes, then shortened to a suitable length: 1.5 mm for the wheel axle, and 2.5 for the arm axle in the chassis.

Soldering the suspension arms

The arms are burnished for discretion.

Burnishing the suspension arms

The wheels are glued with CA glue. They will not roll any more (they never did, by the way).

Gluing the wheels on the arms

Click on the picture to see the wheels better.

Assembly

The arms are inserted in the chassis. They are not glued, so the suspension height can be adjusted.

Mounting the wheels on the chassis

Click on the picture to see the assembly.

The interior is put back in place, then the chassis is put back into the body, and fixed with an M 1.6×3 screw.

View of the screw fixing

Result

Front three-quarter view.

Front three-quarter view

You can see that the suspension is not perfectly adjusted…

Rear three-quarter view.

Rear three-quarter view

Before and after comparison.

Before/after comparison, front view

The expected double effect is there: the car underside is clearer, and the rear wheels are further apart.

Before/after comparison, rear view

There is still one horror to eliminate: the locking system.