Thread: sway bars and corrugations

Originally Posted by copba

G'day,

Can someone clarify which vehicles had sway bars fitted from factory?

My 02 110 Extreme doesn't have front or rear fitted. I kind of doubt that the previous owner removed them, as it wasn't used for 'hard' off roading, and is stock standard.

Cheers,

Al

Yeh, 02 Xtreme doesn't have bars as standard.

Originally Posted by Lotz-A-Landies

Have you seen where the G Wagen 6X6 have the sway bar for the 2nd axle?

It's at the front on the trailing arms and works directly connected to the diff housing without the connector rods needed when it's fixed to the chassis at the rear.

yep and those things flex....

like a go kart.

Originally Posted by bushrover

Yeh, 02 Xtreme doesn't have bars as standard.

Thanks for that bushrover,

With all the talk about County's having them as standard, and some Perenties, it seemed strange that my TD5 doesn't.

Mine's a little 'rolly' around roundabouts etc. but it handles well, and is quite predictable as long as you keep the speed to an appropriate level.

But its a Defender, and they can't go too fast any way. If they had the Disco TDV6 in them, I reckon they'd need them then.


Cheers,

Re sway bars on County's: it is probably because they had the self levelling unit with lighter coil spring rates, thus needing a sway bar - just my wild guess!

Originally Posted by Bush65

Re sway bars on County's: it is probably because they had the self levelling unit with lighter coil spring rates, thus needing a sway bar - just my wild guess!

Thanks for your condolences earlier John.
Where I get confused with the effect of sway bars on corrugations is with respect to damper rates. If the dampers are valved to correctly control the rebound force from soft/light coils for when both wheels on the same axle strike bumps simultaneously, as on corrugations where a swaybar will have little effect, how can the same valving cope with the increased rebound rate of 2 springs when the swaybar is working on single wheel bumps? If the damper is valved to control single wheel bounce, including the increased spring rate and rebound force that the swaybar contributes, then I would have thought that the valving would be too stiff to allow the springs on both sides to react quickly enough on double wheel bumps, where the spring rebound rates are less. To my feeble mind, with admittedly only a basic understanding of damper technology, either setup would contribute to rear end skitteryness and possible loss of control on corrugations.
Bill.

Hi Bill

I would also like to offer my condolances.

But back to to the topic.
Most dampers have two circuits, high speed and low speed, which correspond to the two different natural frequencies a suspension system has.
Low speed and low frequency is the motion of the body moving on the springs. This is controlled through the low speed ports which are often free-bleeds or bypass circuits. Sometimes adjustable, mostly not.
High speed and high frequency is the motion of the wheels and axles moving up and down with the body staying more or less steady. This is bump control and in the damper is is usually stacks of flexible shims covering the ports in the piston. These shim stacks can be tuned in size and shape to provide an endless number of combinations giving an endless range of damper bevhaviour. From linear damping force vs shaft speed to progressive or regressive with shaft speed.

The two circuits interact and any given high speed movement will move through the low speed range (before the high speed ports open) both at the beginning and end of each stroke. On both compression and rebound.

On rebound a high speed port is needed to allow a wheel to return rapidly to the ground if it loses contact on the back side of a bump. It must let the wheel move fast enough that contact and traction are maintained. Essentially the high speed circuit is about controlling rebound rates to prevent overshoot or oscillation, the low speed rebound circuit is there to control body motion.
The effect of the sway bar increases the rebound spring rate to cause the high speed rebound to occur even faster. This can be a good thing to keep the tyre planted on the back side of the bump. But at the same time it reduces loading on the opposite side tyre. Nothing is free.

Overall I see the benefit as a positive one until the single sided bump effect on the sway bar starts inducing body motion.

Stave my puma has got a sway bar on the rear while the td5 did not have.
I also have a long range tank that extends below the chassis rails and I have put in spacers to bring the bar below the tank. The puma handles better with less body roll than the td5 did without the bar.

I haven’t read all the posts so forgive me if this has already been covered.

My 85 county with LL sill in use. I had horrible lean on cnrs so i went down the track of sway bars etc.

At the moment I have none. But what I do have is good shocks ( more good luck than management) it is quite noticeable that if i enter a roundabout at slow speed IE from a stop she wants to fall over. But if i drive in she’s as flat as.