Rear anti roll bar

[bullstarz]

Looks like it might be possible to fit an anti roll/sway bar to the rear suspension on a Stag. I know that it will be once again trial and error.

Has anyone fitted one.

Saw these online for TR6

[Seaking]

Steve
have a look at
http://www.monarch-stags.co.uk/productinfo.php?id=20 or http://www.britishv8.org/Triumph/BarryRicketts.htm

Cheers Glenn

[Lingen]

Steve. Where do you then mount the shock absorbers?
The monarch kit is not an anti-roll bar. It is to control the "Twitch" caused by the driveshaft splines locking under load. If you have modified driveshafts there is probably no point in fitting it.
Mike.

[mjheathcote]

Monarch used to sell a rear anti roll bar kit, but stopped many years ago for some reason?

[bullstarz]

Steve. Where do you then mount the shock absorbers?
The monarch kit is not an anti-roll bar. It is to control the "Twitch" caused by the driveshaft splines locking under load. If you have modified driveshafts there is probably no point in fitting it.
Mike.

Those photos are a TR6. I'll keep the separate spring and damper can't see the point in coil overs at the moment. The roll bar would have to be mounted on the underside of the spring/trailing arm or shock/trailing arm.

Yes my drive shafts are a modified Nissan GSTS with 200sx hubs so they wont suffer from anything hopefully.

[Guest]

Monarch used to sell a rear anti roll bar kit, but stopped many years ago for some reason?

You wouldn't want to fit a rear anti roll bar to a Stag, it would oversteer like crazy, then it would swop ends so fast you would only blink in the wet before rear ending.

Those Triumph cars fitted with front roll bars, handle very well (2.5pi Estate, Stag).
They give a healthy understeer warning as STD, before twitching around the rear.

If you look at that photo above it's the rear suspension on the TR6.
It's a system is totally utterly compromised by having the trailing arms attaching to a low point on a chassis.
It was their way of squeezing a compact IRS into miniumum space, but for geometry it's a mess.
The roll bar as shown is also a mess, because the fulcrum point is totally out of alignment with travel.
Who on earth thought that up?

TR4A IRS-TR6s gives variable degrees of toe in/toe out during suspension travel, which has always made the rear end quite violently unstable.
The classical (bodge) to make the TR6 stop twitching around, is to inhibit suspension travel by fitting the hardest possible springs that can be squeezed in + thickening the front roll bar.

This makes the car have a back breaking ride as well understeer a lot more in the wet.
I can't think of a worse way to try to improve handling, but that's what everybody and their dog buys!

(My solution was to let the suspension travel using my own design, bespoke progressive rated springs varying from as soft as original rating to up to 3x stronger under travel. This approach works, and doesn't stress the chassis.)

The Stag & 2.5pi saloons simply don't have anything remotely close to the TR4-6 rear instability because the trailing arm is a totally different shape with a much higher attachment point. (thank goodness!).

If you look at the rear suspension on a typical Porsche 2.7RS, you will start to understand how they tame this trailing arm behaviour.
It's quite similar to the Stag, as is the rear end of a Sierra Cosworth.

My old (2L pi) estate was fitted with a Salisbury plate type LSD & improved front & rear springs.
This was for me the ultimate sideways motoring experience.
It's suprisingly quick in the corners.

There's several 2.5pi Mk1 being used for circuit driving in Australia.
They are very very fast in the corners.
I developed some special springs for them, and they have proper Koni dampers.

[mjheathcote]

You wouldn't want to fit a rear anti roll bar to a Stag, it would oversteer like crazy, then it would swop ends so fast you would only blink in the wet before rear ending.

Those Triumph cars fitted with front roll bars, handle very well (2.5pi Estate, Stag).
They give a healthy understeer warning as STD, before twitching around the rear.

In fairness, the rear bar they did sell was to complement their uprated thicker front anti roll bar, so not just to add to the car with just the standard sized front bar.

[Guest]

Yes this is the "crazy" Revington kit.
This badly thought out thing makes the car unbelievably uncomfortable.

Being as the chassis is the weakness on the TRs all such people are ending up doing, is making the roll stiffness and spring rating higher than the torsional stiffness of the chassis, then claiming it makes the car handle like a dream.. grief!

It's one of the worst ideas anyone could dream up,- actually worse than SPAX or other needle valve dampers (if it's possible to imagine.)

(Spax dampers were nicknamed "snaps" in Silverstone racing school, because they were so crap)

A combination of 450lb linear rate rear springs stiff roll bars and all that c..p for 2 1/2 grand?
I can get a much better result for a fraction of the price, it's beautifully comfortable and will drive around the outsides of a Porsche 911 on a circuit.

[kev100]

Yes this is the "crazy" Revington kit.

I can get a much better result for a fraction of the price, it's beautifully comfortable and will drive around the outsides of a Porsche 911 on a circuit.

Can I ask what you recommend, I will be looking for improvements to the suspension, and if you know of a better system at a reasonable price I would like to look into it.

Cheers
Kev

[Guest]

Can I ask what you recommend, I will be looking for improvements to the suspension

Is this for the saloon/stag trailing arm derivative or the TR4A-6?
That's "my thing" I did on R & D.

I have a strong belief in the "WINDOW", a combination of the spring & damper rate curves crossing at the same time as camber-caster-toe in geometry becomes absolutely optimal.

Sometimes the "insane" route is the right one...like the syndrome:- errk...

"I think I might have overdone it this time

This often turns out to be an intuition of being "spot on".

If it's for a Stag,-
The stag is basically identical to the Mk2 pi, with a couple of small detail changes to the rear chassis legs.
The front suspension is the same apart from the slightly larger Stag brakes, a sort of stabilised macpherson, so it's all long travel stuff.


For those cars,the bloke you want to have a chat to is Andy.
I supplied him some bits, so he might have something left over.

Here was my little brain wave accompanied by some decent dampers:-


Andy's important tweaks:-


One of the beasties which is now "all steel 2.7L", (using my pistons, head & special design cam).


Both of them are chasing each other's times and determined to see off the Datsun 240Zs for good. (They're now very close to doing it!)

I recommend using a plate type LSD on the saloon/stag, but fully built up they don't come cheap.
I have to take a flight one of these days & pay them all a visit.

[Carboy0]

Down_the_plug_hole

I like the looks of the springs/shocks and the four pot calipers and vented discs.

I'm a Stag newbie and don't know Andy, I'd love to know more if there are details, or a contact address for 'Andy'.

[bullstarz]

I have fitted a front strut brace which apparently is one of the best things for the macpherson strut suspension.

I went for Wilwood calipers up front as i have always found them to be one of the best with Alcon vented disc.

The shocks are Gaz which i have found very good. I have fitted a LSD (Toyota) as well and the back end never broke loose. There again it was only used on the roads.

The whole idea of a rear roll bar was to keep the car flat in a bend and allow more power to be put down before losing traction. Which in my car if traction is lost and the revs rise as a result things will go horribly wrong, very quickly. The higher the revs the higher the boost the less traction, a vicious circle until impact.

[Guest]

Not wishing to upset anyone.
GAZ shocks were done originally by exactly the same bloke as AVO. (A guy called AVON suprise suprise).

They are needle valve dampers and suffer the most appalling fade as well as being totally untuneable for anything else but rebound.
As the oil cavitates, the bump setting then goes to pieces as it does with all the other "adjustable" needle valve crap dampers like Spax, Avo etc etc.

You will notice Andy (Thompson from PERTH), uses proper Koni dampers which have a totally different high speed damping characteristic from a needle valve system, can be stripped down and retuned/rebuilt and generally tweaked to give you proper bump and rebound settings to make a car handle properly.

You can get him via his funny blog.
He has also just rebuilt a Stag engine.

Konis do NOT fade or suffer cavitation.
I know this because I make/have made bespoke dampers with factory parts, which are then checked and set up on a SPA dyno.
I notice down in OZ, they found the strut brace did make a big improvement, but notice they are using Mk1 Pi cars which are under 1000kg.

They are very very quick in the corners, on one occasion I remember laughing when it was related how a Nissan Skyline came zooming past on the 1st lap, only to be overtaken on the inside some 2 laps later, as his brakes turned to smoke.

To me the most impressive cars have always been those that go round corners.
Forget all the rest!

[bullstarz]

I have had no problems with my Gaz shocks and was told by a shed load of people that these were one of the best, that's why i got them opposed to Spax (and others). Plus when i spoke to the then owners Warren and Mark Gazzard they were very helpful.

Spax replied to what Down_the_plug_hole said

"Very funny fairy story & interesting reading. We were an engineering company who manufactured most of the components for Spax, Avo & Woodhead & a fair few were designed by us or improved & we decided to make our own dampers back in 2000 & now produce over 3000 units a month & support many race championships who have to use our kits as mandatory fitment. Most of the dampers we manufacture are a twin tube setup the same as Koni & their ex sales director used to work for us & we know many Koni service agents & how they work but if this person wants to have his own opinion then I am not going to worry about him, wouldn’t surprise me if he is a koni supplier.

Regards

[Guest]

wouldn’t surprise me if he is a koni supplier.

No, I deal with Koni factory and a very smart specialist on the continent.

I refuse to have anything to do with most BRITISH dampers suppliers.

One thing for sure they would laugh their socks off at Spax.
If you want further souvenirs, a SPAX damper nearly killed me and a passenger when it suddenly sheered off at the root of the thread, we rolled a cabrio violently with no roll cage.
Ever since that experience I have no hesitation telling everyone that Spax are dangerous SH T.

I and a friend were nearly gonners....