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I have a basic understanding of the function and physics behind anti-sway bars. However, I'm sure that there is an added twist when dealing with surfaces other than tarmac.

What are some setups that people are running out there for sand, gravel, etc. with regards to anti-sway bars? Are people running front and rear? Front only? Rear only? None? If running any, what sizes are being used for rally?

Is this based on trial-and-error or analysis? Can you provide some reasoning?

Thanks for you input.
 

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I usually run without a front sway bar but with the rear one. The logic behind it is that on a very rough surfaces as long as you have enough spring your front wheels will stay on the ground more with out the bar leading to more traction which is really what you are going for on loose stuff. This is something that dates from my days running a MkI VW and that my DMS were manufactured wrong so the "ears" broke the swapbar end links at full lock.

I really comes down to personal preference since it is an easy way to tune the handling of the car. Run a couple of stages with it. Then run some without it and see what you like / can you notice a difference.
 

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Like Andrew, I run no sway bar on the front and have stock on the rear for loose surface events. Actually I've left the stock front sway bar in place and just remove the dog-leg connectors.

Simon
 

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kind of digging up an old thread here but it is a fairly common question.

For gravel it is often better to control body roll with spring rates rather than sway bars. That way it allows your suspension to be completely independent so driving over a rock with one wheel won't upset the geometry of the other three. A lot of people cure understeer by adding a larger diameter rear sway, or deleting the front, because it is cheaper. But for gravel it is often preferable to have even or slightly stiffer spring rates in the rear, to dial out understeer. It is also a good idea to have slightly stronger rebound dampening in the rear. This way when you turn into a corner the inside front wheel will droop faster than the inside rear to fight understeer. For tarmac it is generally best to run a larger diameter rear sway bar than the front sway bar. But at the end of the day it all comes down to driver preferance and budget.
 

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^As above, I run no swaybars on the rally car. I have never run the front one, though I did run the rear for a few events but found that it made the car twitchy. From what I've heard it all comes down to driving style; of course suspension setup would probably make a difference too. I like the idea that each wheel has full independant motion through all of it's stroke.

Setup wise we run

-2 Front camber
-1.5 Rear camber

1/32 Front toe in
0 Toe rear

It goes straight under power.
 

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What are you using to adjust camber front and rear on your car?
 

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Setup wise we run

-2 Front camber
-1.5 Rear camber

1/32 Front toe in
0 Toe rear

It goes straight under power.
Do you run front toe-in for straight-line stability and to reduce steering effect from bumps?
Do you have any issues with it pushing on turn-in?

Thanks! I'm just learning to dial in my rally car.
 

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What are you using to adjust camber front and rear on your car?
We have aftermarket front camber plates. In the rear we have custom 1" O.D. tubular DOM steel tube with heimjoints for toe arms and control arms so those just get turned in or out to adjust camber and toe. If you take a look at the "Aggressive weight reduction for rally" thread that I started in the zetec tuning section you can see them in the rear (they're lime green of course!).

We do also run the Ford Racing rear subframe with camber adjustment but have eliminated that as this is much simpler.
 

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Do you run front toe-in for straight-line stability and to reduce steering effect from bumps?
Do you have any issues with it pushing on turn-in?

Thanks! I'm just learning to dial in my rally car.
We run just a touch of toe in because the front wheels tend to toe out under power with FWD, so it gives a straight track when you're on the pedal. As for bumps I don't know if that impacts steering, personally I haven't noticed it you just need to prepare your car for what's coming ie. take the right line and know what will unsettle the car/throw it this way or that way.

As for pushing on turn in, not at all! We even run 2psi lower in the back for a little understeer. If you stay on the gas (this is the key to fast FWD), left foot brake and run a proper plated differential with the right settings (1.5way plated diff. at 60% lock) it's just magic!
 

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We run just a touch of toe in because the front wheels tend to toe out under power with FWD, so it gives a straight track when you're on the pedal. As for bumps I don't know if that impacts steering, personally I haven't noticed it you just need to prepare your car for what's coming ie. take the right line and know what will unsettle the car/throw it this way or that way.

As for pushing on turn in, not at all! We even run 2psi lower in the back for a little understeer. If you stay on the gas (this is the key to fast FWD), left foot brake and run a proper plated differential with the right settings (1.5way plated diff. at 60% lock) it's just magic!
I think you'll find this interesting:
Grassroots Motorsport Mag camber/caster/toe guide

referring to FWD or independently suspended RWD: "When driving torque is applied to the wheels, they pull themselves forward and try to create toe-in. This is another reason why many front-drivers are set up with toe-out in the front."

Toe out can cause the car to wander over uneven surfaces so that is why I thought you might run toe in.

And: "toe-out encourages the initiation of a turn, while toe-in discourages it." So that is why I was wondering if you had any issues with understeer on turn-in.

But it sounds like you're happy with your setup and that is what counts! The setup has to suit the driver.
Thanks for the advice.

another resource:
Longacre Racing guide
 

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I think you'll find this interesting:
Grassroots Motorsport Mag camber/caster/toe guide

referring to FWD or independently suspended RWD: "When driving torque is applied to the wheels, they pull themselves forward and try to create toe-in. This is another reason why many front-drivers are set up with toe-out in the front."

Toe out can cause the car to wander over uneven surfaces so that is why I thought you might run toe in.

And: "toe-out encourages the initiation of a turn, while toe-in discourages it." So that is why I was wondering if you had any issues with understeer on turn-in.

But it sounds like you're happy with your setup and that is what counts! The setup has to suit the driver.
Thanks for the advice.

another resource:
Longacre Racing guide
Fair enough, having read the article, I admit that I made an assumption on the fact that fwd cars toe out under power. I actually borrowed these settings from someone who raced a Focus prior to me and assumed that was why. Evidently it would be for straight line stability which is why I didn't notice an issue with that ever; keeping in mind of course that 1/32" toe in is pretty minimal but probably enough to keep it straight combined with the toe in effect of applying power (remembering of course that we don't have the grip levels of tarmac).

So basically correlation is not causation as per usual lol.

But I do recommend you try this setup as it's worked well for us!
 

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I agree 1/32" of toe probably has little effect when on gravel. But alignment changes are usually only made a few degrees at a time.

I noticed that Kenny Block's "HFHV" appears to have gobs of positive caster and so that is why I really got into researching this (the angle of the steering pivot axis may not be as radical as the angle of the coilover):

It's pretty cool how positive caster causes the wheel to gain camber as it is turned.

P.S. Its kinda funny how this thread is almost three years old and pretty off topic.
 

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I agree 1/32" of toe probably has little effect when on gravel. But alignment changes are usually only made a few degrees at a time.

I noticed that Kenny Block's "HFHV" appears to have gobs of positive caster and so that is why I really got into researching this (the angle of the steering pivot axis may not be as radical as the angle of the coilover):

It's pretty cool how positive caster causes the wheel to gain camber as it is turned.

P.S. Its kinda funny how this thread is almost three years old and pretty off topic.
I know that the positive caster on the strut is a trick used to be able to run a longer damper. Being that Ken's car is a WRC car, he's probably using the same 60mm cannons that the WRC guys are that are suuppppeerr long. I can't remember if they were 60" long? At any rate they're huge.

Of course the positive caster helps the straight line stability. I also know that the aluminum front control arms that come on some of the Subaru STi's give the cars a +5 caster and this is on a street car.
 

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For loose surface, Like andrew and simon, i run no front bar. But I found i prefer it without a rear as well. Ran with and without it. Have to use left foot braking more to get the car to rotate but I personally had better stage times.
 

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Except for my last rallycross, I ran the whole season with stock ZX3 front and rear bars.

For my last race,I disconnected the front and tied it up-left the rear alone...seemed to work good..WAY more traction immediately apparent-even on the street.

In 2 days i try my new setup-ditched the 129 lb. svt front springs for some taller 175 lb. (was having front bottoming issues), still disconnected bar in front, and 24mm bar now in rear.

I'll post up how that works....
 

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Just a few notes on performance handling...

ADJUSTMENT INCREASE UNDERSTEER INCREASE OVERSTEER


Front tire press Lower Higher
Rear tire press Higher Lower
Front tire section Smaller Larger
Rear tire section Larger Smaller
Front Camber More Positive More Negative
Rear camber More negative More positive
Front springs Stiffer Softer
Rear springs Softer Stiffer
Front roll bar Stiffer Softer
Rear roll bar Softer Stiffer
Weight dist Move forward Move rearward


Hope this helps a bit...
 
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