Limiting rear up travel.

[Struth]

My thoughts are to limit the up travel on the rear 5 link by extending the bump stops down by 1 1/2".

this is to hopefully force the front 3 link to work more and reduce how much the rear works.

The aim is to prevent the body from simply following the front suspension and it's limited flexibility compared to the rear.

Can expect any other adverse effects other than less up travel on the rear suspension.

Cheers[/u]

[sudso]

It'll try to force the drooping side down more at the rear because the extended bump stops will act as a pivot point if you know what I mean. That can be a good thing if you have longer shocks than normal for your lift as it will apply a bit more ground pressure (= traction) to the drooping side. The extended bump stops will stop your longer shocks bottoming out too if you make them the right length.
And yes it will make the front flex a bit more but only once the rear has reached it's max.
I find that GU slotted bushes help get a little more flex out of the front too.
Cheers

[80's_delirious]

are you talking about extending them further than what is needed to prevent tyres rubbing or shocks bottoming out? I dont see any other advantage

[gu town]

what they said...^

maybe a rear sway bar if you dont have one? heavier rate springs?

[Struth]

are you talking about extending them further than what is needed to prevent tyres rubbing or shocks bottoming out? I dont see any other advantage

Shocks do not currently bottom out and tires scrub only just at full flex.

I am trying to reduce the flex in the rear so that the front works more and also so that the body doesn't simply lean over to whichever way the front is inclined (this is a bad symptom of the rear being too flexible in comparison to the front.

The aim is to get the body to stay more level when articulated.

Cheers

[Struth]

what they said...^

maybe a rear sway bar if you dont have one? heavier rate springs?

Rear sway bar may be the answer, but it currently handles real well on road without one, the issue is that I need to stiffen the rear offroad.

Cheers

[thehanko]

what they said...^

maybe a rear sway bar if you dont have one? heavier rate springs?

Rear sway bar may be the answer, but it currently handles real well on road without one, the issue is that I need to stiffen the rear offroad.

Cheers

Then its needs stiffening, not reduction of flex IMO.

sway bar or slightly heavier rate spring so that it is balanced with the front.

if you just limit the total travel of the rear, it will still flex to the bumpstop on the rear then start on the front same as it is now.

[Guy]

what they said...^

maybe a rear sway bar if you dont have one? heavier rate springs?

Rear sway bar may be the answer, but it currently handles real well on road without one, the issue is that I need to stiffen the rear offroad.

Cheers

That may well be (handles OK on road) more due to the stiffness of the front than the softness in the rear ..




I know that reads soooooo wrong but I dont care

[Struth]

what they said...^

maybe a rear sway bar if you dont have one? heavier rate springs?

Rear sway bar may be the answer, but it currently handles real well on road without one, the issue is that I need to stiffen the rear offroad.

Cheers

That may well be (handles OK on road) more due to the stiffness of the front than the softness in the rear ..




I know that reads soooooo wrong but I dont care

Yes that reads wrong, but you are right

[Struth]

what they said...^

maybe a rear sway bar if you dont have one? heavier rate springs?

Rear sway bar may be the answer, but it currently handles real well on road without one, the issue is that I need to stiffen the rear offroad.

Cheers

Then its needs stiffening, not reduction of flex IMO.

sway bar or slightly heavier rate spring so that it is balanced with the front.

if you just limit the total travel of the rear, it will still flex to the bumpstop on the rear then start on the front same as it is now.

Yes that does make sense, thanks.

Cheers

[351ciofgrunt]

I think you should leave the rear alone

If the rear flexs well then leave it and concentrate on fixing the front.

The problem is the front not the rear

So work on getting more flex out of the front, GU slotted control arm bushes (if you have a GQ), softer flexi-springs, remove swaybar etc

If you limit your rear flex then you'll be limiting your 4wd capabilities, not increasing them

[Guy]

I think you should leave the rear alone

If the rear flexs well then leave it and concentrate on fixing the front.

The problem is the front not the rear

So work on getting more flex out of the front, GU slotted control arm bushes (if you have a GQ), softer flexi-springs, remove swaybar etc

If you limit your rear flex then you'll be limiting your 4wd capabilities, not increasing them

I disagree .. if your car is all floppy etc it will be a pig offroad .. also if your not getting a good split of flex front to rear it will be less successful 4wd than one with less (within reason) but more balanced flex.

That massively flexed up rear may still have a tyre on the ground but will have stuff all traction to it.

This is one reason so much work goes into front suspension setups on 80's Patrols, Suzukis, Dudluxs etc as the back usually pox's all over the front for articulation.

[351ciofgrunt]

So instead of improving the front, you want to punish the rear?

I say if the:

Rear flexs well - good

front flexes poorly - improve it

[Struth]

So instead of improving the front, you want to punish the rear?

I say if the:

Rear flexs well - good

front flexes poorly - improve it

Yes I agree partially, but it's a daily driver, and how would you suggest improving the flex on an 80 series 3 link front, that has only just been installed instead of a 5 link.

Cheers

[351ciofgrunt]

Well if you want it to be a daily driver then to a certain extent you will have to sacrifice offroad ability

[Gwagensteve]

Well if you want it to be a daily driver then to a certain extent you will have to sacrifice offroad ability

This is untrue, and is a legacy of the idea that a loose, floppy car is better to drive offroad than a controlled car.

Name one parameter of suspension performance that changes between on and off road use.

Roll stiffness? Nope - a 4WD will see more lateral G offroad than on.
Flex? Not relevant on road, but not a problem so long as the design parameters are right.
Spring rate? Nope
Shock valving? It's been 10 years since I thought it was cool to reduce shock valving off road.

It's perfectly possible to build a car that handles well on road and off road.

Struth - you need to add rear roll stiffness. Lowering the bumpstops won't achieve this. Adding spring rate isn't a great way of increasing roll stiffness, although this depends on your spring location.

Adding a swaybar will be the best option. It can be very effective and the small amount of lost rear travel will be more than compensated for by the car sitting flatter on obstacles and working the front harder, especially when climbing.

Steve.

[80's_delirious]

are you talking about extending them further than what is needed to prevent tyres rubbing or shocks bottoming out? I dont see any other advantage

Shocks do not currently bottom out and tires scrub only just at full flex.

I am trying to reduce the flex in the rear so that the front works more and also so that the body doesn't simply lean over to whichever way the front is inclined (this is a bad symptom of the rear being too flexible in comparison to the front.

The aim is to get the body to stay more level when articulated.

Cheers

thought that was what you meant but wasn't sure.
I cant see how longer bump stops will help. I think it will just mean the diff housing will be further away from the chassis when the rear suspension flexes up. This would still happen before the front if the rear is more compliant, rear diff would just be in a different position in relation to the chassis.

[Struth]

are you talking about extending them further than what is needed to prevent tyres rubbing or shocks bottoming out? I dont see any other advantage

Shocks do not currently bottom out and tires scrub only just at full flex.

I am trying to reduce the flex in the rear so that the front works more and also so that the body doesn't simply lean over to whichever way the front is inclined (this is a bad symptom of the rear being too flexible in comparison to the front.

The aim is to get the body to stay more level when articulated.

Cheers

thought that was what you meant but wasn't sure.
I cant see how longer bump stops will help. I think it will just mean the diff housing will be further away from the chassis when the rear suspension flexes up. This would still happen before the front if the rear is more compliant, rear diff would just be in a different position in relation to the chassis.

My thoughts were with limiting up travel on rear the point where the front is forced to work will come sooner.

[Struth]

Well if you want it to be a daily driver then to a certain extent you will have to sacrifice offroad ability

This is untrue, and is a legacy of the idea that a loose, floppy car is better to drive offroad than a controlled car.

Name one parameter of suspension performance that changes between on and off road use.

Roll stiffness? Nope - a 4WD will see more lateral G offroad than on.
Flex? Not relevant on road, but not a problem so long as the design parameters are right.
Spring rate? Nope
Shock valving? It's been 10 years since I thought it was cool to reduce shock valving off road.

It's perfectly possible to build a car that handles well on road and off road.

Struth - you need to add rear roll stiffness. Lowering the bumpstops won't achieve this. Adding spring rate isn't a great way of increasing roll stiffness, although this depends on your spring location.

Adding a swaybar will be the best option. It can be very effective and the small amount of lost rear travel will be more than compensated for by the car sitting flatter on obstacles and working the front harder, especially when climbing.

Steve.

My discussions with club members and input from people such as yourself, as well as Rockcrawler31 (who is investigating the same problem on his ATM) have lead me to beleive that a sway bar on the rear is the best first approach on this prob.

Yes it will lose a little bit of what is pretty excessive flex anyway, but that is why it has twin locks, to keep going when wheels are not grounded.

ATM I am going to investigate a Curry bar attached to either the chassis and the lower arms, or the chassis and the axle housings.

It will have the added advantage of improving what I think are pretty good road manners already.

Cheers

[Gwagensteve]

It's not really that simple - adding bumpstop length has no effect on roll stiffness - you'll end up with the suspension drooping more easily from the leverage, and a higher COG.

The rear will still go to full travel before the front can flex - so the effect on balance is basically zero.

Your car needs more roll stiffness, not less travel. They're not the same thing.

Steve.

[dano80]

Another vote for rear swaybar and maybe some flexy arms on the front.

Cheers, Dano.

[dano80]

What the hell is a Curry Bar?

Is that where the Curry Munchers go?

Dano.

[Struth]

What the hell is a Curry Bar?

Is that where the Curry Munchers go?

Dano.

It's a sway bar really, only made from a torsion bar and using the splines on each end to attach arms to.

Cheers

[Struth]

It's not really that simple - adding bumpstop length has no effect on roll stiffness - you'll end up with the suspension drooping more easily from the leverage, and a higher COG.

The rear will still go to full travel before the front can flex - so the effect on balance is basically zero.

Your car needs more roll stiffness, not less travel. They're not the same thing.

Steve.

That's right my thought was however that it would prevent the body from laying over quite as far as it currently does. But it would not effect the amount of droop that is acheived on the opposite wheel, it might even increase it???


But yep roll stifness will be the first thing done to help redress the excessive bodyroll when offroad.


Cheers

[sudso]

So instead of improving the front, you want to punish the rear?

I say if the:

Rear flexs well - good

front flexes poorly - improve it

Yes I agree partially, but it's a daily driver, and how would you suggest improving the flex on an 80 series 3 link front, that has only just been installed instead of a 5 link.

Cheers

Are you saying you've got 80's radius arms on the front or a whole 80's front? They should flex better than Patrol arms anyway because the front bush eyes are closer together than Patrol arms. Also 80's series front arms are closer to centre on the 80's diff housing than Patrols too.
The main limiting factor is the 3 link design itself. Slotted bushes is worth a bit more flex and softer front springs will allow it to flex more rapidly and with less weight distribution or invreased stiffness from the rear but it will still only flex to the limits of the 3 link design no matter what spring rate or sway bar you have. In other words you could have 7 inch articulation coils and 18" shocks but it's still not going to flex or travel beyond what the 3 link will allow.

[gu town]

what they said...^

maybe a rear sway bar if you dont have one? heavier rate springs?

Rear sway bar may be the answer, but it currently handles real well on road without one, the issue is that I need to stiffen the rear offroad.

Cheers

i believe the sway bar will stiffen the rear. and shouldnt limit flex very much if set up right.

i've been reading alot about these super flex arms and thats what alot of people are doing to "force" the front to work to keep the cab more level. i think its an easy thing to try out. im sure plenty of people would be willing to give away their unused sway bars.

i'd atleast give it a go before starting some big custom job

if it does make a difference, but not enough then these curry bars you speak of may well be your answer....

[Struth]

So instead of improving the front, you want to punish the rear?

I say if the:

Rear flexs well - good

front flexes poorly - improve it

Yes I agree partially, but it's a daily driver, and how would you suggest improving the flex on an 80 series 3 link front, that has only just been installed instead of a 5 link.

Cheers

Are you saying you've got 80's radius arms on the front or a whole 80's front? They should flex better than Patrol arms anyway because the front bush eyes are closer together than Patrol arms. Also 80's series front arms are closer to centre on the 80's diff housing than Patrols too.
The main limiting factor is the 3 link design itself. Slotted bushes is worth a bit more flex and softer front springs will allow it to flex more rapidly and with less weight distribution or invreased stiffness from the rear but it will still only flex to the limits of the 3 link design no matter what spring rate or sway bar you have. In other words you could have 7 inch articulation coils and 18" shocks but it's still not going to flex or travel beyond what the 3 link will allow.

Costom 5 link rear and custom 3 link front with 60s diffs on a 4 Runner.

Front flexes very well when forced but rear is currently too flexy to force the front before the body rolls.

[Struth]

what they said...^

maybe a rear sway bar if you dont have one? heavier rate springs?

Rear sway bar may be the answer, but it currently handles real well on road without one, the issue is that I need to stiffen the rear offroad.

Cheers

i believe the sway bar will stiffen the rear. and shouldnt limit flex very much if set up right.

i've been reading alot about these super flex arms and thats what alot of people are doing to "force" the front to work to keep the cab more level. i think its an easy thing to try out. im sure plenty of people would be willing to give away their unused sway bars.

i'd atleast give it a go before starting some big custom job

if it does make a difference, but not enough then these curry bars you speak of may well be your answer....

The problem with the superflex arms is that they are all built with castor correction, for big lifts.

Mine has a big lift but standard RAs with custom castor plates on the axle housing.

Cheers

[gu town]

i just re-read my post. i worded it wrong i think. i wasn't suggesting superflex arms. i was suggesting that the people who have those arms were re-installing their rear swaybar to "force" the front to work like you are trying to acheive..

[tim75b]

i can attest to a rear sway bar forcing the front to work better i fitted mine up with disconnects so i could disconnect it off road but it works a whole lot better off road with the rear bar connected





these are both with swaybar connected