IFS, Sway Bars, and the new Tacoma

[Alphonse]

Good info, thanks guys. You have addressed my concerns and answered my questions thoroughly as expected.

My swaybar is off and is staying that way. My commute is only about 5 miles and in traffic at 60mph tops, and after driving without the swaybar for 2 days I am finding the slight increase in body roll manageable and the ride is actually less harsh as well. (Not that donahoe coilovers are harsh, but you know what I mean.)

From a quick excursion yesterday offroad I also definitely feel the rig is sitting more level on uneven terrain as well.

I think for my rig set up the way it is the tradeoff is well worth it.

 

[TBranco]

These photos were posted earlier, and they show the problem perfectly.
Notice in the front view, the tire is up on a rock; but the body is being forced to lean heavily, and the tire on the rock is not being stuffed into the wheel well.

Then look at the view from the rear. The rear suspension is being forced to do all the work.

The rear is on level ground, and the rock is forcing the right front tire and the body over to the side. This is what wears out the driver. The front suspension is too stiff; either from a swaybar or stiff springs. This suspension is tall; but it is NOT working well, and the driver takes a beating.

That truck looks familiar! With or without the swaybar, the IFS is still going to be the same. Maybe a little more flex but not much! An LT kit would allow more travel and flex and allow the CV angles to go further! Personally, I'm over my drop bracket kit! No regrets though...it has taken me many places a 3" lift wouldn't have. I left the sway bar on in those pics to keep the CV's from flexing too far since that trail is pretty rocky! I will be doing an SAS and before I cut out the IFS I'm going to test the CV angle without the sway bar. I'm curious now to see how well they hold up!

 

[Photog]

I must say, that is a nice looking truck.

When discussing IFS & flex, CV joints are always a concern. Most of the lifted IFS trucks don't get all the flex that the CV joints will allow. A sway bar should have no effect on the life of a CV joint; because it does not control suspension travel.

Example: If you drive fast, into a dip, the left and right suspension will rise an fall together, and the swaybar will not be involved. The suspension may go to full compression, and as you come out of the dip, the suspension may go to full extension. If this compression or extension is more than the CVs can take, then something is missing; but it has nothing to do with the swaybar.

If anyone wants to keep their CV joints healthy, they need to have proper suspension travel stops installed; typically limiting straps and/or bump stops.

From the factory, IFS has a fair amount of flexability. Then we install stiffer springs, to get some lift, and much of the flexability goes away. A straight axle will have the same problem, if it has stiff springs. The point is, we need to install springs that add lift, and not a lot more spring rate. We will loose downtravel, but we should still have access to the uptravel.

When flexing on the trail, you want one tire to be able to move up, while the other can move down. This is what a swaybar will prevent, on IFS or straight axle.

 

[TBranco]

I must say, that is a nice looking truck.

When discussing IFS & flex, CV joints are always a concern. Most of the lifted IFS trucks don't get all the flex that the CV joints will allow. A sway bar should have no effect on the life of a CV joint; because it does not control suspension travel.

Example: If you drive fast, into a dip, the left and right suspension will rise an fall together, and the swaybar will not be involved. The suspension may go to full compression, and as you come out of the dip, the suspension may go to full extension. If this compression or extension is more than the CVs can take, then something is missing; but it has nothing to do with the swaybar.

If anyone wants to keep their CV joints healthy, they need to have proper suspension travel stops installed; typically limiting straps and/or bump stops.

From the factory, IFS has a fair amount of flexability. Then we install stiffer springs, to get some lift, and much of the flexability goes away. A straight axle will have the same problem, if it has stiff springs. The point is, we need to install springs that add lift, and not a lot more spring rate. We will loose downtravel, but we should still have access to the uptravel.

When flexing on the trail, you want one tire to be able to move up, while the other can move down. This is what a swaybar will prevent, on IFS or straight axle.

Great points! This is why I prefer a solid front axle...one tire goes up, and the other is forced down which gives you 4WD instead of just 3. I think a quick disconnect sway bar would be the best way to go. Too bad they dont make them for all 4WD vehicles to begin with!

 

[ntsqd]

snippage.......

When flexing on the trail, you want one tire to be able to move up, while the other can move down. This is what a swaybar will prevent, on IFS or straight axle.

I think you've hit on the cause. One tire on a live axle influences the other tire. This (& the high unsprung weight) is the root of why LA's classically do not ride as nicely as do IFS'. To the limit of the travel range an IFS truck should be more compliant than a LA truck on any type of surface because the extending tire isn't being interfered with by the compressing tire's spring & vice versa.

Roger Brown's technique of using diagonally opposite car ramps in the driveway is a great way to evaluate the status of a truck's suspension. Which ever 'axle' the body favors (leans with) is the less compliant suspension. If both suspensions are equally compliant then the body will be level to the driveway.
He goes on to use blocks to raise the ramps, thereby increasing the "articulation" all while sitting on flat ground. This is also a great way to check for binding, tire rub, and other potential problems at the travel extremes.


I've previously stated what I think the solution is. A longer, lower rate spring installed with more pre-load. A 200 lbs-in spring installed with 2" of compression carries the same load as a 400 lbs-in spring installed with 1" of compression, only requires a further 200 lbs loading to compress another inch vs. the 400 lbs-in spring needing twice that.

At some point in lowering the spring rate & increasing the free length dynamic stability will be calling for the sway-bar to be re-installed. Any off road resulting harshness of ride means that the swaybar's spring rate is too great for the application. Enter products like Currie's "Anti-Rock."

 

[Cackalak Han]

I had some quick disconnect sway bar endlinks from www.wabfab.org and they worked great (for my 3rd Gen 4Runner). They are 20 times more stout than the flimsy factory endlinks. I don't see that they have the 4th Gen 4Runner/5th Gen Tacoma endlinks on there, but I'm sure he'd be willing to fab some up. Might be worth looking into.

Broken stock endlinks...

WabFab endlinks on my 4Runner:

When my OEM endlink broke(on the driver's side), I could definitely feel the sway on the road. Left turns vs. right turns really showed how much the sway bar limited body roll. Like others have said, off-road wasn't a dramatic difference, but I believe the benefit was there. Photog makes some great points.

 

[Photog]

This is SOAZ's 4Runner. It is flexing as well as an IFS can flex. Full stuff & full extension, without making the body lean or lifting a tire. He said it rides much more comfortable off road, than his previous setup.

 

[Alphonse]

This is SOAZ's 4Runner. It is flexing as well as an IFS can flex. Full stuff & full extension, without making the body lean or lifting a tire. He said it rides much more comfortable off road, than his previous setup.

That is outstanding! What is the set up on this 4 runner?

 

[techGary]

The pic above is the true benefit of a non sway bar truck, both sides of the suspension can move without effecting the other side, less sketchy leaning on the trail, more on the road. Search around tons of disconnect setup available and they dont need to be purpose built for the tacoma, just have to fit through the holes and be within an inch in length of the stockers.
Added bonus it looks really cool when you come around an uphill corner by your house, throttle pinned and a front tire 4" off the ground!

 

[Photog]

That is outstanding! What is the set up on this 4 runner?

He said he reduced the preload on the DR coilover springs, and removed the swaybar. He left in the rear sway bar, to transfer some of the twisting load to the front, and help highway manners.

This thread started asking about swaybars on the latest gen of Tacomas. So far, I do not know of any good quick disconnects for the new Tacoma/4Runners. But; if you have installed some lift springs that are stiffer than stock, you can certainly do without the swaybar.

If one of the spring manufacturers would make a front spring, with the factory spring rate, in a series of extra lengths, we could have the flex we want, the lift we need, and a need for quick disconnects for the swaybar.

 

[ntsqd]

On the drive to work this morning I got to wondering how the aftermarket spring rate(s) compare in generating the desired undamped 3-5 Hz natural freq in the suspension. I'd have to look up the math, and even then I'm not sure it's something I'd want to tackle, but I'm curious all the same.

 

[Spikepretorius]

That articulation is blerrie marvelous for an IFS

 

[slooowr6]

If one of the spring manufacturers would make a front spring, with the factory spring rate, in a series of extra lengths, we could have the flex we want, the lift we need, and a need for quick disconnects for the swaybar.

Can't find info on the OEM spring rate for 05+ tacoma. Anybody has this info?

OME 886 has 660 lb/in
OME 885/884 has 590 lb/in
DR come with 650 lb/in

 

[Jacket]

IIRC it's around 550 lb (at least that's what my memory tells me)

 

[Photog]

These are the numbers for the latest generation of 4Runners.

V6: 16mm x 340mm - 7.75 coils - 3.7kg - 580lb/in
V8: 16mm x 345mm - 7.75 coils - 3.7kg - 580lb/in

The V8 coil is 5mm longer than the V6 coil.

OME specs:
Front:
883 - 17mm x 375mm - 10.6 coils - 5.7kg - 590lb/in
884 - 17mm x 385mm - 10.6 coils - 5.7kg - 590lb/in
885 - 17mm x 395mm - 10.6 coils - 5.7kg - 590lb/in
886 - 18mm x 402mm - 12.5 coils - x.xkg - 660lb/in

The 884 gives a 4Runner a 3" lift, but feels quite a bit stiffer.
There are 3 more coils added in, and it is 45mm taller than stock.