As above has anyone doubled up the rear ARB to make it stiffer?

Don't think you would want to double up the rear ARB. You can use uprated Whiteline 22mm (same thickness as OEM but stiffer) or 24mm. There is also Eibach which I believe is 23mm but it comes with the front ARB so much more expesive than Whiteline. General consensus here was that Whiteline 22mm is the way to go for fast road plus some track days. Whereas the 24mm for a track-oriented Coupe.

It's a very popular upgrade amongst my Saab buddies..

http://uksaabs.co.uk/UKS/viewtopic.php?f=3&t=75773

http://www.uksaabs.co.uk/UKS/viewtopic.php?f=3&t=31227

Stock rear ARB is 19mm.
Check the link in my signature.

Whiteline does not produce rear ARB now, neither Eibach or Novitec.
We are trying to male them by italian supplier.

Ultra racing 23mm is available. They come with brackets too

Final Price shipped to Europe?
I asked some months ago and it was circa 170 euros shipped + taxes, and we don t have feedback about ultra Racing...

So no one has actually tried it? I'll have to have a look to see if the ARB can be spaced a few mm from the original. Obviously the end 2/3 inches will need angle grinding off. It would be a very cheap alternative.

Can you post a simple scheme to explain it?

Pretty self explanatory.

Novitec do a 23mm Rear I've got one fitted

Interesting
Give it a go and post the results. The forum is always interested in new thoughts & ideas

interesting idea

Happy to give it a blast. Just need and old rear ARB.

Well, as they say you learn something new everyday. I hope that it won't be too stiff. Let us know.

I think that in this way you Will have a top stiff arb.
You have to take a book of building engineering and see How to calculate static moment of a 22mm circle and of two 19mm circle bar linked together, taking into account also the distance between one bar and the other.

I think that use double bar is not a good idea, no no..

It's worth a shot

The first picture makes sense as it's fully linked, the ones that are bracketed one fill me with fear, just not had time to work out why.

Phil, are you talking saabs of the vectra chassis era? The wooliest cars ever?

A couple of the photos are from Saab's of the GM era but the others are from the 9000 which handled pretty well for a barge. ARM still sell the piggy rear anti roll bar for the 9000.

http://www.abbottracing.net/product.php?id_product=103

135 gbp? We are searching for make arb at 160gbp.. But one pièce only not this strange Construction..

I was just using it as an example of what's available. If I do it it will be piggy backed with an old standard ARB. £160 Is great for a bigger rear ARB. £160 plus import tax, VAT etc + shipping is not so great. It'll end up too close to other kits available.

160 + shopping, nothing else

http://goo.gl/sCqK1D

Which = €280

Which = £205

Which = http://m.ebay.co.uk/itm/271338062333?nav=SEARCH

Some person don't trust in whiteline.. I don't know why..

Although I understand that the relationship between diameter and stiffness isn't linear, I can't help but think that TWO standard ARBs is going to be a fair bit stiffer than even the beefiest aftermarket ARB (which I believe is the 24mm Whiteline)

When I tried the 24mm, I found it too much for the road, especially with my front-end mods as well

I imagine two 19mm ARBs will have you pirouetting at every corner and it would be a nightmare on fast sweepers

Think its worth remembering the piggy Arb isn't attached by drop links etc at the ends. The space between the 2 Arbs also has a contributing factor regarding how "stiff" it becomes. I'll definitely look into this and hope to have an old ARB in my possession in the next week or so to try this out.

Think the braces between the two would be most important as these are transferring the load.
I'd have thought there position, quantity and construction would be very important.

Here's an interesting read, scroll down to the double bar section:

http://www.autospeed.com/cms/article.html?&A=112694

Nice find.

So, by my calculations, the % increase in stiffness of the options available to us are:
19mm 0% (i.e. standard)
19mmx2 100.0%
22mm 79.8%
23mm 114.7%
24mm 154.6%

Are we sure that Coupe rear ARBs are solid? (I've never hacked one in half to find out)

From reading the article linked by Jimbo, it would appear that if they're tubular, the ratios don't work in the same way