panhard to rear-that old nugget

[a7grenade]

            what a brilliant and active site this is

I've trawled through many links to do with this subject but none quite hit the mark
i have a riley engined special (sorry) and have run it for many years on its original set up (built on a budget) but now getting some upgrades including a tube style front end which i think I'm fine with the set up and many of you have commented on which has helped-thanks

I'm looking at the rear now at the same time which has been fairly standard ish and its been fairly awful
i was, looking to add the oft used radius arm connected to the chassis leg up to the rear axle as on many single seaters and possibly a panhard rod from some extra cross box framing run under the torque tube and mounting friction shocks further rearwards as many run successfully 
but my engineer helper is throwing up the question of using the triangulation as per attached image from the green book (can't upload at the moment-will keep trying)

do the vscc frown on this? or as I'm a special anyway is it ok (shhh-its out of sight) 
and what is best out of the two main ideas?

i have flat springs in the usual position 

i know its adding weight but i would like some more chassis structure further back from the chassis ends to offer more body support
it currently is mounted off the rather thin chassis extension
and the last box/cross section is before the end of the chassis - it does have rudimentary cross bracing as the seat support but of no real benefit
not shown in photo

the car is mainly for sprints but is used occasionally on the road and already has a harsh ride so thats not a problem
my son has aspiration to race it and it needs to be respectful for vscc entry

its more of a special than an austin so i don't think we need to be fully period correct-maybe?

over to you-with thanks

[Greig Smith]

That's a very pretty looking little special, I particularly like the Riley diamond pattern in the louvres to suit the Riley engine

Can you post a few more pictures ??

Aye
Greig

[a7grenade]

thanks greig-i will-my mac is effing me about at the moment-as soon as i can
cheers

[Ian Williams]

Agreed nice looking car. What problems are you having with the back end? I imagine a lot more power transmission than most of us with A7 engines. I know one or two sevens have run Panhard rods but as you suggest somewhere to mount is an issue, there were some pictures of John Miles set up on here somewhere. Additional clamps around the rear springs to stop the leaves sliding sideways on themselves when cornering help slightly and must be accepted by VSCC, but hey its a vintage special, and IMHO it needs to perform as a vintage special. Not sure when Panhard rods on rear axles came into common use, I may be completely wrong, but my gut says post war??

[Stuart Giles]

Looks great, and must have useful performance too. I triangulated to the ends of the chassis extensions on my '32 special when I fitted a Panhard rod on the rear, there is also a sheet metal bulkhead which carries the shock mounts as well as the drop bracket for the Panhard rod. It has really sharpened up the cornering, especially because the car, being an old trials car, has cambered springs at the rear.

[Bob Culver]

If you watch the shots of bouncing in trials chummies I think you will be content with the original chassis extensions!
I cannot figure what all the tubes do in the Austin photo.
Is there any other known application where a panhard rod is used but a more or less rigid lateral spring location retained? I guess if the springs can handle the normal spacing changes with roll they can handle the panhard rod. I dunno exactly where the original roll centre is but presumably lowering the roll centre is the virtue.
Dunno if allowed but I found hydraulic lever shocks transformed rear end of a saloon, but increased tyre load related oversteer.

[Roger Goldthorpe]

Copied from Wikipedia.

'A Panhard rod (also called Panhard bar, track bar, or track rod) is a suspension link that provides lateral location of the axle.[1] Originally invented by the Panhard automobile company of France in the early twentieth century, this device has been widely used ever since.'

I assume early 'twentieth century' will be pre war?

Roger

[Bob Culver]

Probably pre Boer War. I dunno the exact origin but early cars often had full elliptic springs and similar with consequent little location.
When straight axles with torsion bars or coils became fashionable a Panhrad rod  became necessary. The traction avante Citroen and Jowett Javelin have, and common in the 70s. A refined version with more uniform characteristics left and right turning is the Watts parallel motion linkage.

[a7grenade]

so are we thinking the full triangulation back to the rear axle is more 750 than vscc ?
i agree with it being vscc/special and look feel and drive like that-thats why we have them isn't it

[Alan]

If you want to know about VSSC eligibility, it’s best to ask them directly for an opinion. The Chairman of their Eligibility Committee posts here and I think he’s an approachable sort of chap.