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The rally Golf was front wheel drive in the FIA Formula 2 series which ran from the mid-'90s to ~ 2000.

There was a 4WD Golf 4 R32 sold to Gran Canaria from the UK, but this was a one-off Group N+ ex-race car, if that's the one you're thinking of.

Seat Ibiza Kit Car Evo 2 rear beam:








Golf 4 Kit Car rear beam.




Same principle, but you have to look harder at the beam to see the point at which there are 2 halves.

There is a sway bar running down the centre of it, though it is independent. Just neat packaging.
 

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Facinating! That's a beefy setup for sure. I can see why with such a large diameter tube they wouldn't be able to make it one piece - a tube that size wouldn't give the flexibility required of a sway bar. I can also understand going to a large diameter tube, rather than the two flat plates welded together, from a strength point of view.

Also interesting is that the triangulation goes not to the middle of the beam, but towards the other pick suspension pick up point, giving a triangulated arm that goes from one pick up point to the other. This prevents any lateral loads from being transferred to the middle of the tube - pretty slick.

Anyway, from looking at it, I'd conclude they separated the two trailing arms for strength reasons - the suspension geometry is still a traling arm design (i.e. no toe/camber change over travel.)

I can't imagine ever bending those rear beam setups - you'd more likely tear off the mounting points on the unibody before those things gave way.

Lastly, for some reason people don't consider our rear beam setups as IRS, though they are. They just have an integral sway bar.

Thanks for the pics!
 

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There's no doubt that strength is part of the explanation for the design.

Both Golf 3 Kitcar and Ibiza Kitcar Evo 1 were standard beams on toe kits. Due to the nature of gravel and rough stages, a quote I have was that the suspension on an Ibiza Evo 1 was fit for the dustbin after one event.

Circuits clearly allow a standard beam to survive far longer.

However, you still have to ask the question why they made them independent. As if to further the point, Ford homologated a special rear axle on the Escort RS2000 F2 car (FWD), again IRS. This was ~ 1995, and again I have a picture some where. Seat created the Ibiza Evo 2 in 1997 and VW finally competed with their long gestating Golf 4 F2 rally car in 1999. The development pattern is indisputable :thumbup:

I don't agree that our beams (Rabbit, Golf A2, Golf A3) are IRS with sway bars. The Rabbit is a T-section on its side, with a bar strapped to it on GTI models, but it is still wholly connected. A2 & A3 have a welded torsion bar, but if it was true IRS, a Rabbit/Golf (non GTI, ie no sway or torsion bar) wouldn't lift an inside wheel on turns. Sure, it's designed to twist, but it's not IRS.
 

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if it was true IRS, a Rabbit/Golf (non GTI, ie no sway or torsion bar) wouldn't lift an inside wheel on turns. Sure, it's designed to twist, but it's not IRS.
It is IRS, with an integral sway bar. If you didn't have this, the car would understeer like mad. The sway bar is required to keep as much traction as possible on the inside front tire in turns. Otherwise, any suspension with a sway bar, whether built in or not, would be 'not IRS.'

Adding a pivot in the middle just defeats the built in sway bar. You'd have to compensate in one way or another (add external swaybars or move to insanely stiff springs in the rear) to get it to handle properly again.

BTW, 911's lift the front inside tire in turns - does that mean they don't have IRS in the front?
 

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I think our belief in what IRS is, differs, which is fine – as long as we respectively know what we’re referring to.

My take on it is that Rabbit/Golf A1-A4 had non-IRS and A5 has IRS. Obviously GTI models have sway bars.

Non-GTI models (A2 + A3) have no integral sway bar. They still lift inside wheels. Non-GTI Rabbits have no strapped on sway bar. They still lift inside wheels. As a clear baseline I personally don’t call that independent, and that’s because inherently they are connected through the beam, one side interfering with the other.

If the sway bar is removed from the Golf A4 rally or Ibiza Evo 2 beam, then the 2 sides are truly acting independently.

I realise what the function of the sway bar is, and how it can affect traction on the inside front wheel, and I realise the implications of not having it present, and the methods available to compensate. But this digresses away from the beam discussion.

I think the most valid point to bring in here is the difference between a standard beam on high rate springs + no sway bar, and one with a large sway bar / additional sway bars. One behaves + handles bumps and ridges very differently to the other. Clearly rally set ups necessitate far more compliance, even on the tarmac stages, and likewise bumpy track set ups err towards a softer spring rate.

However, my interest in this thread is mainly to show the beam designs being debated and to show where works inspiration took the technology. Moving that on, I wonder if another part of the answer lies in set up precision: a two-half bearing rear beam removes any “spring rate” associated with a standard flexing rear beam (normally an unknown, variable rate, according to twist?). Bearings would then allows a far more precise car set up, via springs, damper rate (bump, rebound, high speed, low speed) and sway bar only.
 

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The thing to look at are the cars that have both beam and IRS like some AWD and non AWD versions of cars. See what they did. I am thinking about this because I am looking to AWD my car and the passat syncro stuff weighs a ton.
 
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