Rear anti roll bar

[KOY 23]

I had Spax adjustable at the rear, the threads were badly formed at the base and the 1/2 nuts stripped them at a few ft/lbs of torque, the fronts had 28 click adjustments from hard to solid. Spax told me that they had since re-valved fronts to make softer but would not offer any discount. Now replaced by fixed KYB's which suit me fine.

John.

[Guest]

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,

It doesn't matter what the shed loads said, they were WRONG.

Anyone who is anything, will tell you the needle valve damper people are in denial, and sure as anything they're never going to tell you their dampers are bad or cavitate.

I did buy some Gaz dampers for a Jag some years back.
6 months later they were leaking like the cr..p they really are.
'nuff said they were promoted by some outfit (classic spares) who were running the whole damn race championship as a nice insider cartel,- suprise suprise!

Of course the other thing nobody will tell you either, NO (budget) adjustable damper EXCEPT koni dual adjustables allow you to set the bump setting, they only set the rebound.

Any suspension specialist worth their salt will always tell you, the bump and rebound ratio are vital to get right.
It reminds me of a Lambo I worked on years ago.
The "shed loads" will always tell you what wonderful cars they are.

They're not.
The understeer was chronic (it would literally wipe out on slow roundabouts) and the lift off oversteer was frightening at exactly the wrong moments.
The dampers had near non existent bump,hard rebound and high spring preload, like nearly all those evil handling "Italian exotica" have.

There are lots of good damper specialist but you will find them working for professional rally teams, like Ohlins, Penske, Reiger, proflex....and of course our humble Koni (or Bilstein) who get fitted as OEM on a lot of good cars.

Funnily enough, a good damper and spring combination is worth any number of extra horsepower, as Seb Loeb will easily tell you.

His damper guy is deservedly world famous, and British.
Their web page says it all does it?:-

World Rally Champions: Subaru 2001 | Citroen Sport 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

[mjheathcote]

When I rebuilt my suspension, 20 years ago now, I fitted the best I could afford, that being Koni and Leda springs.
The Koni being adjustable off the car only, and the the Leda springs lower, and slightly stiffer at the front. The rear springs if I remember correctly are already 400lb from the factory.
Been no problem at all in all that time.
Would have like the Leda dampers, but too rich at the time. Not sure if Leda are still trading I recall they went under at one point.

[Guest]

Leda appears to have some connection with Harvey Bailey nowadays.
As far as I remember their dampers were also needle valve types.

I've had Harvey Bailey modified cars to work on.
They were some of the most lethally dangerous vehicles I have ever driven,- absolutely terrifying in the wet.

I came so close to crashing it several times it was one of the fastest suspension conversions I have ever done to get shot of all that rubbish.

The first thing to be thrown away was their oversize front roll bar which gave it chronic understeer.
Then I realised they had managed to attach the rear roll bar to the body while attaching the ends of the bar through over compliant bushes to the bottom wishbones which mounted to the diff and subframe (Jag dual wishbone suspension).

WTF was that idea?
The problem was, simple, the suspension and subframe would wind up until the bushes all compressed to max, then the thing would suddenly develop a rear roll resistance, and BANG would snap into the most terrifying oversteer.

So, what you got was, poor turn in with no feel,then build up of a little resistance in the steering, followed by the car sailing straight on in wet roundabouts, followed by a very sudden horrific desire to swop ends.

You couldn't make it up,- literally, all of the worst of all worlds one after the other, like some death wish.

People must have been swearing at me all the time watching the antics of this so called "modified thing" going all over the road.

[bullstarz]

Admittedly the front inserts are adjustable for rebound only but i'm sure the rears will adjust bump and rebound off a single control knob. You can adjust both while still on the car. I have no idea what they would be like on the track, but for road proposes there far better than standard.

I know that control for both bump and rebound independently would be better. However, years of riding bikes with more suspension adjustments than you can shake a stick at for bump, compression, rebound and preload, sometime its hard to find that sweet spot.

[Guest]

i'm sure[COLOR=#333333] the rears will adjust bump and rebound off a single control knob.

How can you be so sure?

There is no damper I know of that can be adjusted for anything else but rebound with an adjuster.
Logic always determines the outcome.
Also it's quite impossible to have an external adjuster for anything else other than a needle valve, which of course it's why you have to remove a Koni to be able to adjust it internally.
(cos of course it's not a needle valve damper!)

On a double adjustable koni, you have a smart little device down the inside of the damper rod which adjusts the bump setting, while the rod itself as usual (for Koni single adjustable too) locks into the valve at full travel to adjust rebound.

Another important feature of a Koni is having the valve right in the foot of the damper.
This makes it possible to have up to an almost 50/50 tube length to damper stroke possibility.
This permits a lot longer suspension travel for a given damper length.

There are other advantages, such as its progressive damping character which is just about the opposite of a needle damper (hence the legendary comfort).

http://www.f1technical.net/forum/viewtopic.php?t=8937

This is a so called Force-Velocity diagram of a KONI damper. It shows the relation between damping forces and the speed of the damper in operation. When a car accelerates, brakes of rolls, typical damper speeds are in the (A) area.

Damper speeds caused by road surface irregularities usually are in the (B) area. Our engineers tune the damping forces in both ranges separately to a large degree. Their aim is an optimum balance between handling and comfort. Whereas Red KONI Special dampers are more biased towards comfort, yellow KONI Sportdampers are so towards handling.

KONI Adjustability - The diagram also clearly shows another unique feature of KONI dampers; their true full-range adjustability. This is essential, since adjusting only part of the characteristics disturbs good balance. The minimum value (full soft setting) is the recommended factory setting. When your driving style requires so, you can easily tune the suspension by adjusting the dampers. This makes your car respond even better but in the same time may change the comfort level. Therefore, we advise to make adjustments in small steps (half a turn) at a time and, of course, in equal amounts left and right.

KONIExternally Adjustable Dampers - These dampers are at the high-end of our range. They can be adjusted while remaining mounted on the car so that damping levels can be adapted to personal requirements in a matter of seconds.

KONI Sport vs KONI Special - The characteristics of shock absorbers hardly ever get the attention they deserve, despite the damper being responsible for comfort, roadholding, stability and safety.

Below is a force velocity graph of a KONI SPECIAL and a KONI SPORT shock, both designed for the same vehicle. The graph displays the adjustment ranges for both shocks. The pink area shows the adjustment range where both shocks are equal in value. The red area indicates that portion unique to the KONI Special, while the yellow area is specific to the Sport shock only.

An example:-






On "normal" dampers such as Spax it's impossible to get close to the 50/50 open closed ratio, because the valve is located a considerable way up off the bottom.
This explains why many of these gaz, spax, avo etc dampers have a reduced stroke such as to be totally unsuitable for the car they are fitted on,-

Hence on the TR6 a spax damper is the WRONG length, it either bottoms devastatingly badly before actually reaching the full suspension travel or bump stops, or it is installed so as not to crash and bottom, but instead runs out of travel and lifts a wheel on full extension..

I have repeated this for the best part of 30yrs but nobody pays attention, and people keep coming in with cars that are all wrong, with bottoming suspension and the wrong damper rates.

I have never understood why people have fitted the WRONG dampers on Triumph cars for decades, put up with the crashing and bottoming, and dreadful ride quality with the WRONG bump/rebound ratios, then claimed somehow it's normal for their type of "sports car".

Strikes me as masochism or denial or both.