Sway Bar Disco Essentially Useless on IFS?

[Comadivine11]

Found this message on a 4-Runner forum. And yes, it is just some opinion on the interwebs, but I thought I'd see what you guys have to say. Essentially the argument is that on an IFS system, only the tire under compression will have traction since the other tire will have near-zero weight load. Also, since articulation on an IFS is mostly limited by the shaft angles and geometry more than the sway bar, the increase in articulation will be minimal at best. Thoughts?

From Sonoran Steel FAQ:

Sway bar disconnects are not needed with an IFS suspension
By disconnecting the front sway bar you may gain a very slight amount of added a-arm droop, but here is the problem with an IFS truck. The only tire that has any weight on it is the one compressed, so it does not matter if the other tire is in the air, almost on the ground or on the ground. It will spin because it has no weight on it.

It is however correct to disconnect a sway bar on a straight axle truck as it will increase articulation. The real benefit of having a straight axle is that both front tires bear the weight at all times, not only one like an IFS truck under articulation.

We do not recommend sway bar disconnects as we have found them to be completely useless on this vehicle.

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[Zraver]

Mostly true for an open diff but the bad lands will ve locked so the wheel under compression will still get power. Add in modern computers able to selectively route wheel torgue and the added articulation will indeed be useful.

 

[SoccerDude]

Well it doesn't seem to be a HUGE difference, but it does make a difference as you can see from the video's. I think they said 5" more travel if I recall right....

 

[Comadivine11]

Mostly true for an open diff but the bad lands will ve locked so the wheel under compression will still get power. Add in modern computers able to selectively route wheel torgue and the added articulation will indeed be useful.

I think what they're saying is that, even with lockers, since one wheel will have little to no weight on it, you won't really be gaining much if any traction from that tire. In a SFA, both wheels bear weight at all times. In an IFS only one wheel is really bearing weight in a off-kilter situation.

 

[Zinn]

Mostly true for an open diff but the bad lands will ve locked so the wheel under compression will still get power. Add in modern computers able to selectively route wheel torgue and the added articulation will indeed be useful.

Aren’t you saying two different things? If the diff is locked then it won’t be routing torque, rather all torque will be evenly split across both wheels - right?

 

[Zraver]

I think what they're saying is that, even with lockers, since one wheel will have little to no weight on it, you won't really be gaining much if any traction from that tire. In a SFA, both wheels bear weight at all times. In an IFS only one wheel is really bearing weight in a off-kilter situation.

Nope tgey were talking the uncompressed tire spinning. Thats open diff not locked.

 

[Buckin' Bigfoot]

Well it doesn't seem to be a HUGE difference, but it does make a difference as you can see from the video's. I think they said 5" more travel if I recall right....

5” of travel is a big difference. (That’s what she said)

 

[Zraver]

Aren’t you saying two different things? If the diff is locked then it won’t be routing torque, rather all torque will be evenly split across both wheels - right?

On older lockers yes, Ford claims the Bronco will be able to apply power to the wheel(s) with traction.

 

[ForestBronco]

I took both sway bars off my 4Runner. Tires can now get stuffed way into the fender. Sway bars affect all suspension types. It’s a solid metal bar connecting both sides. Wanna see it in action? Droop your suspension like on a lift or with a jack, then zip off your sway bar end link and watch your suspension instantly drop several inches due to being unloaded.

 

[Natai]

I think it will depend on the situation.
Disconnecting the sway bar is going to drop suspension on both tires. So if your tire with the lightest load was at least close to making contact, it should end up with an increased weight load.

Sure, you could put yourself into a spot where even with the sway disconnect, one tire isn't making contact, but having the sway disconnect increase the travel for both wheels should minimize the chances of that.

 

[Bison]

Yeah the bronco looks to get more droop then my Fj so regardless it’s better. I took mine off the Fj so it would not break the links and stab my cv boot. Haven’t had it on for 60,000 miles. I won’t do the rear as one of my springs will pop out unless I do some extra work.

 

[Comadivine11]

I understand what a sway bar does. The point I'm trying to make isn't that it won't increase travel but that that travel doesn't really matter because if there's little to no weight on the tire that can now droop further, you're not gaining any more traction than if said tire was hanging.

Having read some other forums since first posting it seems that some other, less intuitive, benefits from IFS disco are that because sway bars limit travel in both directions, disco will allow the compressed tire to compress even further and, secondly, having the front disco'd can actually help the rear tires stay planted by giving the vehicle better balance.

 

[aplm7]

Couldn't you argue that the disconnect isn't only for traction for the tire, but also for stability? It means your wheel in the air is going to find the ground sooner rather than crash towards that side so much. And it's going to get weight bearing compression sooner

 

[guernsej]

I understand what a sway bar does. The point I'm trying to make isn't that it won't increase travel but that that travel doesn't really matter because if there's little to no weight on the tire that can now droop further, you're not gaining any more traction than if said tire was hanging.

If your tire is an inch off the ground and you disconnect the sway bar to get an extra couple inches of droop, once that tire makes contact it's going to compress and load that tire to some weight equal to or greater than your spring preload. You're also going to get better compression on your opposite tire unless it was already fully stuffed.

Disconnecting the front sway bar won't get you to SFA levels of articulation but it's not going to be useless.

 

[guernsej]

The real benefit of having a straight axle is that both front tires bear the weight at all times, not only one like an IFS truck under articulation.

Nonsense. I've seen plenty of flipped jeeps whose tires stopped bearing weight at least once .

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