IFS, Sway Bars, and the new Tacoma
- Thread starter Schattenjager
- Start date
OK, after lurking on this site for about a year I am finally going to jump in here since I have been following this thread for a while and it's got the wheels in my head turning.
After reading this thread and giving it alot of thought I removed the front swaybar today from my Donahoe Coilovered FJ Cruiser. My main concern was what you see pictured below:
(As you can see the passenger tire is barely stuffed while bearing all the weight.)
Now after driving it I have a few thoughts below and would like to get some opinions since you guys seem to know what you are talking about.
Benefit of No Swaybar as I see it is that it keeps body roll down and possibly maintains driver side tire contact longer in the picture above.
If traction is a simple factor of force/area then wouldn't 1 tire receiving 100% weight = 2 tires receiving 50% weight? So one of the No Swaybar benefits is really an imagined benefit?
Now for IFS besides the obvious on road body roll issue when running no swaybar on road I am thinking there is another more serious issue for the offroader. In the picture above imagine a tree stump is dead center at the top of the crest. W/O Swaybar wouldn't your front end be sitting lower and thus suffer more impacts due to less clearance?
The biggest benefit for IFS offroad (Non Baja racing) is the extra front ground clearance, but when you remove the swaybar aren't you significantly reducing this benefit?
Just wanted to throw these thoughts out there and see what others had to say. For now my Swaybar is off but I am not sure if it will stay that way yet.
Regards,
Alphonse
After reading this thread and giving it alot of thought I removed the front swaybar today from my Donahoe Coilovered FJ Cruiser. My main concern was what you see pictured below:
(As you can see the passenger tire is barely stuffed while bearing all the weight.)
Now after driving it I have a few thoughts below and would like to get some opinions since you guys seem to know what you are talking about.
Benefit of No Swaybar as I see it is that it keeps body roll down and possibly maintains driver side tire contact longer in the picture above.
If traction is a simple factor of force/area then wouldn't 1 tire receiving 100% weight = 2 tires receiving 50% weight? So one of the No Swaybar benefits is really an imagined benefit?
Now for IFS besides the obvious on road body roll issue when running no swaybar on road I am thinking there is another more serious issue for the offroader. In the picture above imagine a tree stump is dead center at the top of the crest. W/O Swaybar wouldn't your front end be sitting lower and thus suffer more impacts due to less clearance?
The biggest benefit for IFS offroad (Non Baja racing) is the extra front ground clearance, but when you remove the swaybar aren't you significantly reducing this benefit?
Just wanted to throw these thoughts out there and see what others had to say. For now my Swaybar is off but I am not sure if it will stay that way yet.
Regards,
Alphonse
ntsqd
Heretic Car Camper
WOW! He really has been moving around, hasn't he? Must be all of the heavily armed illegals manning the pot farms in Humbolt that chased him away.
A sway-bar has no spring rate as long as both tires move together, like when going over a speed bump. It only has a spring rate when one tire is moving relative to the other.
So removing it should have NO effect on ride height. If it did, it usually is because of the friction in the bar's bushings.
Sway-bars limit body roll by reducing articulation. Removing it should increase both body roll and articulation.
Unfortunately traction isn't that simple. On a hard surface it can be that simple, though not always, but each different type of soft surface is unique.
Unless purpose built, most IFS designs have less clearance than a solid axle, not more. I feel that unless you're rock crawling that it's a moot point.
A sway-bar has no spring rate as long as both tires move together, like when going over a speed bump. It only has a spring rate when one tire is moving relative to the other.
So removing it should have NO effect on ride height. If it did, it usually is because of the friction in the bar's bushings.
Sway-bars limit body roll by reducing articulation. Removing it should increase both body roll and articulation.
Unfortunately traction isn't that simple. On a hard surface it can be that simple, though not always, but each different type of soft surface is unique.
Unless purpose built, most IFS designs have less clearance than a solid axle, not more. I feel that unless you're rock crawling that it's a moot point.
DaveInDenver
Middle Income Semi-Redneck
It's not bearing all that much weight, the way you are angled up like that. On flat ground or point nose down, it would have stuffed more. Or maybe if you had the yeti (that showed up when the contrast was raised) sitting in the passenger's seat... It does look like you are getting some up travel on the right wheel anyway compared to the droop of the left one. I think a solid axle truck would have lifted its left wheel there, too, though.Alphonse said:
I think he's right in saying that static, sitting on pavement IFS will have more clearance between the front cross member than a third member of a solid axle. Usually the low point on the front end is a ball joint, though, so depends on where you measure. But obviously as IFS compresses, the cross member dives straight for the ground. My front skid plate proves that, I get to beat dents out of it all the time.ntsqd said:
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ntsqd
Heretic Car Camper
Concur, nose high like that has most of the vehicle's weight on the rear tires.
It would be splitting hairs, but I disagree. The reason being that, using our earlier yota's as an example, while the SA has an 8" ring gear it only has the clearance toyota deemed necessary for the lower part of the housing to clear the RG by plus the metal's thickness. While the IFS has the necessarily thicker casting surrounding it's 7.5" RG followed by the various suspension related bits that pass under the diff casting. Whatever skidplate there might be will need to have some air gap btwn it's top and the bottom of the IFS diff housing. The stock angle in the CV's tends to be limited for various design constraints and the engine usually limits upward space so I doubt that the front diff can be moved up enough to gain much clearance.
Still, I don't think it's all that important unless rock crawling or similar.
It would be splitting hairs, but I disagree. The reason being that, using our earlier yota's as an example, while the SA has an 8" ring gear it only has the clearance toyota deemed necessary for the lower part of the housing to clear the RG by plus the metal's thickness. While the IFS has the necessarily thicker casting surrounding it's 7.5" RG followed by the various suspension related bits that pass under the diff casting. Whatever skidplate there might be will need to have some air gap btwn it's top and the bottom of the IFS diff housing. The stock angle in the CV's tends to be limited for various design constraints and the engine usually limits upward space so I doubt that the front diff can be moved up enough to gain much clearance.
Still, I don't think it's all that important unless rock crawling or similar.
Photog
Explorer
Science time: With a straight axle suspension, when one tire gets stuffed, and the other (extended) tire is still on the ground, the load is not 50/50 on each tire. It takes a lot of force to compress that spring, and stuff that tire; and it takes a lack of force, to allow the other tire to extend downward. With a vehicle in this position, look at the sidewalls of the tires. The stuffed tire will be compressed, and appear half flat. The extended tire will appear to be fully inflated. This does not happen when both tires are equally loaded.
Now, if the SA suspension had stiff springs, or a sway bar, it would lift the unloaded tire, just like the IFS. Also, the body of the truck would have a much higher tendency to to lean and bounce, as it followed the front suspension. A flexible suspension allows the axles to articulate in opposite directions, and the body can stay somewhere in between. This is a lot easier on the occupants, as they don't get thrashed as much.
Our IFS can act more like a flexible SA, if we remove the swaybar. There are other things that can also be done, and we may get into that; but this thread is about the swaybar. Without the swaybar, the front suspension will be allowed to move as freely as it can, without forcing the body to move with it; thereby reducing the thrashing of the occupants.
Now, if the SA suspension had stiff springs, or a sway bar, it would lift the unloaded tire, just like the IFS. Also, the body of the truck would have a much higher tendency to to lean and bounce, as it followed the front suspension. A flexible suspension allows the axles to articulate in opposite directions, and the body can stay somewhere in between. This is a lot easier on the occupants, as they don't get thrashed as much.
Our IFS can act more like a flexible SA, if we remove the swaybar. There are other things that can also be done, and we may get into that; but this thread is about the swaybar. Without the swaybar, the front suspension will be allowed to move as freely as it can, without forcing the body to move with it; thereby reducing the thrashing of the occupants.
Photog
Explorer
I once read an article, where a fellow installed the opposite of a "swaybar". He installed a pair of Air-Shocks from Gabriel, and connected the valves together. When one shock became compressed, it tried to force the other shock to extend.
When going through whoops, both shocks were compressed, adding spring-rate. When articulating, the shocks forced the suspension to move a little further, and unload the forces on the body.
The Toyota XREAS suspension works this way; but from corner to corner, instead of from side to side. Maybe it could be modified for the front only, and remove the rear components for better shocks. Hmmmm.
When going through whoops, both shocks were compressed, adding spring-rate. When articulating, the shocks forced the suspension to move a little further, and unload the forces on the body.
The Toyota XREAS suspension works this way; but from corner to corner, instead of from side to side. Maybe it could be modified for the front only, and remove the rear components for better shocks. Hmmmm.
I think the main thing I am considering is now is this, is the possible loss of ground clearance under certain conditions enough of a detriment to keep one from removing the swaybar, or do the benefits of it's removal outweigh this possible negative effect. (Strictly speaking about wheeling and not on road driving.)
In other words, if I had no swaybar in that pic above then the passenger tire would be stuffed more, and if thats the case then the front end of the FJ (under the skid) would be closer to the ground (in that pic).
Like if I imagine a tree stump or rock in the center of that crest I could see where the swaybar which keeps the passenger tire from stuffing and thus lifts the front might be a benefit in such a case.
In other words, if I had no swaybar in that pic above then the passenger tire would be stuffed more, and if thats the case then the front end of the FJ (under the skid) would be closer to the ground (in that pic).
Like if I imagine a tree stump or rock in the center of that crest I could see where the swaybar which keeps the passenger tire from stuffing and thus lifts the front might be a benefit in such a case.
ntsqd
Heretic Car Camper
Several to many threads on that air shock trick on the 4xwire forum. I think in the Toyota specific forum with regards to the pre-Tacoma IFS.
Sonny Honiger (sp?) used a design that the Toyota is patterned after on his "Scorpion" many years ago. Their effects are the same though the methods employed are different.
Sonny Honiger (sp?) used a design that the Toyota is patterned after on his "Scorpion" many years ago. Their effects are the same though the methods employed are different.
Photog
Explorer
ntsqd said:
I remember seeing that suspension on the Scorpion. It was very interesting. The whole rig was interesting.
As for the "Stump" scenario, that is what skid plates are for. It is a very specific situation, and one that isn't a huge problem, even if it happens. Being thrashed by your front suspension, on every trail you drive, becomes very fatiguing. Trail fatigue causes many folks to make "rookie" errors by the end of the day. I think a few scratches on my skid plate is a better deal.
Another problem we get, with the IFS, when we install lift springs is, we loose down-travel, and the up-travel is much stiffer. So it becomes much more difficult to use the available articulation in the supension. On the trail, this has a similar effect to a soft suspension, with a stiff sway-bar, except in the whoops.
Photog
Explorer
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.
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.
DaveInDenver
Middle Income Semi-Redneck
It's really a pretty unimportant difference and I would agree that there's probably not much difference on stock trucks. On my truck there is a less clearance under the middle my rear diff than at the middle of the front cross member, but I have torsion lift and that pushes the A-arms down, cross member up. The lower ball joints are way low. But yeah, no matter the configuration, it's splitting hairs since any additional clearance is quickly eaten up as the cross member heads south.ntsqd said:
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This is definitely true. Even in rock crawling I think people get too worked up over SAS this and that. I've seen guys in very stock trucks do fantastic and having all the right bits and pieces does not guarantee you'll make it cleanly.