Lomax 223 rear wheel problems.

[cmwbob]

To answer a few of the queries raised in last few posts.

1. The official Cradley Motor Works (Lomax) rear arm mod always included strengthening webs comprising 4mm x 25mm (or 3mm x 30mm) flat bar rolled to match the arm profile. This support is essential to counteract the additional torque leverage and the potential weight overload on the single rear wheel. Sketch attached for those wanting to do a DIY upgrade.

2. The twin inner facing rear wheel setup, to create the impression of a three wheeler whilst retaining 4 wheels was an option supplied in Holland where 3 wheel new builds became outlawed. The body kits were provided with a special wide inner rear arch and yes they did fit within the std rear boat-tail.

[cmwbob]

found some pics of modded rear arm

[cmwbob]

Bit more info on Lomax 223 rear arm issue,

A 223 with modded / extended std arm will have a safe maximum rear axle load of 250kg and the vin plate must show that for axle 2.

A 223 with web strengthened extended arm will have a safe maximum rear axle load of 340kg and the vin plate must show that for axle 2.

Any 223 sporting a Citroen vin plate showing anything higher such (as 500kg or 550kg) for axle 2 is illegal for use on UK highways.

The above figures are derived from technical discussions and agreements between Cradley Motor Works, Citroen UK (Homologation) and DVLA/VOSA and the basis of issue of a Lomax Certificate of Conformity.

[AlanM]

Thank you Moon Monkey for the link to the photos, I like it!

Thank you Bob for the additional info. The modified rear swinging arm (complete with axle tube) that is surplus to my requirements, is not strengthened and was provided by the Mumford motor works. Mind you being rated at 250kg that’s should still give a reasonable amount of luggage etc. carrying capacity.

[Rocketman1955]

What was the suspension configuration with dual rear wheels? Were there 2 active suspension arms?

Interesting item above about the rear axle loads with & without strengthening webbing. Was the revised lower rating for the Mumford parts just because they were a different supplier or due to issues?
I might go single seat & leave the wife and dog at home in future to be safe!
Also from the sketches, the Crawley Motor Works webbing only reinforces the arm not the joint behind the back plate where the deformation appears to be. The original deformed arm on my Lomax had webbing on the arm extended to the bottom of the backplate, but it was still the joint behind the backplate that failed in tracking instead of camber (see pictures)
Fortunately changes seem to be slow and easy to check, but a robust solution would be good without major re-design.

[AlanM]

Hello Rocketman

I was waiting for someone with more knowledge than me to reply to your question, but here is my offering.

From memory the two swinging arms were swapped round left to right although part of the original outer bearing housing area on each swinging arm was ground down to enable the bearings to seat properly.

Both spring packs remained unaltered and the wheels/swinging arms could operate independently; i.e. if one wheel caught the edge of a bump or pot-hole the other wheel would be relatively unaffected.

Fitting the wheels must have been a bit tricky though as there wasn’t a lot of room to get your hand in to fit the wheel nuts and tighten them.

Alan

[howardjs]

Regarding the rear arm from Lomax... here is a photo taken on the Lomax stand at Stoneleigh in about 1995-6 It is the cutaway body demo car revealing the "works" Not surprising that fully loaded the arm was subject to torsional deformation
Howard

IMG_0002.jpg (86.31 KiB) Viewed 47106 times

[cmwbob]

Hi Howard,

Absolutely correct, That photo of the exhibition cutaway 223 shows very clearly the issue with the earlier/original rear arm mod.

Later versions use a larger dia extension tube as well as the webs.

Also as Rocketman discovered the attachment of the extension tube to the backplate is critical. When splicing the backplate it is essential to leave a reasonable section of the original arm stub that can be securely inserted and welded within the larger dia extension tube.

Bob

[moon monkey]

Hi Bob, could you clarify when the strengthening webbing was used? In one post you say it was "always" done, in another you refer to "later versions" -- so was there a time that this strengthening started? Thanks.

[cmwbob]

The rear arm strengthening was introduced in early 2000's, around the same time as the early potholes seemed to become a way of life and the very occasional failure number increased dramatically.

From the outset in the 80's until late 90's it was almost universal practice by the kit constructors to just tack the 2cv vin plate on their 223 pride and joy. Those vin plates would incorrectly suggest the safe rear axle load was 500 kg (or more). It was this type of poor practice which saw the inevitable introduction of SVA (MSVA) and hence the subsequent agreement for rear axle weights and the availability of CMW/LOMAX Vin Plates.