Citroën rear suspension (1):
Atlas
Original page created on 29/04/2023; updated 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
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.
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…
Click on the picture to see the machining.
… then 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…
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.
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.
The arms are burnished for discretion.
The wheels are glued with CA glue. They will not roll any more (they never did, by the way).
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.
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.
Result
Front three-quarter view.
You can see that the suspension is not perfectly adjusted…
Rear three-quarter view.
Before and after comparison.
The expected double effect is there: the car underside is clearer, and the rear wheels are further apart.
There is still one horror to eliminate: the locking system.