Who has the best factory suspension?

2WD or 4WD?

4WD would be GM, and IMHO, no point for discussion for reasons I've beaten to a pulp already.

2WD, probably not much difference, but no real frame of reference to comment.

4WD 2nd Gen Dodge had the panhard problems in addition to typical live axle issues, but I'm told upgrades fix that problem.

Ford 4x4 had similar issues, but again, upgrades fixed it, but I seem to recall it was a mount brace they needed?

 

I won't argue the live front axle is ultimately stronger and easier to lift and such. But have you towed (relatively) heavy with and IFS 4x4 and compared to a solid axle 4x4, particularly on sectioned concrete or "swoopy" roads and turns? IFS tows just as solid and steady as a 2WD. As someone who has towed a fair bit with both, and SFAs for most of my life, I can tell you without a doubt that a 2WD or IFS will be much less work and much more "steady", particularly when tail low with a heavy load. That's because the unequal length control arms and IFS complexity will "adjust" the caster, camber, and toe dynamically. Same reason it handles dips and ruts better.

Even if you have airbags or something to keep the level stance, there is a definite difference in behavior when you hit bumps or "crown" the road. It's not a *huge* deal, but it is noticeable and worth considering. I don't even have to touch the wheel when I have a load and hit a dip, and I don't have to correct crowning the road, something I have had to do (to greater and lesser degrees) with all SFA trucks I've towed with. It's just that much more comfort when towing long distances to no have to actively "drive" the truck the whole time. I like "point and shoot" no brain driving particularly when towing. But maybe it's just age…

So, IMHO, this is another of those points where there is no "right answer". The clearly both have their strong points, and I happen to think they are superior for most towing applications due to the behavior described above. But I defend IFS vigorously not because I'm a diehard fan, it does have its drawbacks and they are well known. And it's not because "that is what I own", rather that is what I own because of the way things I value and the goals I had. But the main reason I'm so vocal on it is because everyone else is so bent on completely writing it off due to ill conceived notions and, for the most part, unwilling to consider it's strong points. If I don’t speak up and make enough noise to be noticed, too many people will get a heavily biased idea on the matter and go for the SFA because "everyone *knows* they are just simply better in every way". I just want to make sure to get the point across that there are pros and cons each way and each person needs to figure out what they value most…

 

Bobby, if you get a chance, haul a heavy load (or heavy tongue trailer) with both and pay attention as you ride on "dippy" roads. Also try it at 75(ish) on a less than stellar freeway/interstate. And also changing lanes across the crown. These are the places I really notice the difference.

But don't look at ride, that's a matter of preference anyway and has no bearing at all on what I'm trying to describe. Pay attention to how much you need to correct and how much it makes you "drive" it. The GM IFS acts the same loaded or unloaded and tracks beautifully. In mine, if I am pointed the right direction, I can pretty much just take my hand off the wheel as it crowns or hits a dip, loaded or not. Sometimes there is a *small* deviation, and of course it needs correcting, but nothing like the solid axle dodge, twin beam Ford (never towed with a live front Ford that I recall, but my father had a twin beam) and older GMs (and no, not worn out) that I've towed with.

Like I said, the thing with live front axles is that the toe in can't change as things move, particularly as the body rolls front to rear with a load. Combine that with a castor that is locked in orientation to the frame (well, not quite if you want to get picky) and you have the reason that load affects the way it drives. No, I'm not saying it becomes a death trap that you have to work your behind off with just to stay on the road, at least not if the load is reasonable. But it does make a noticeable difference. A difference large enough that to some, myself included, it overshadows the potential future benefits of the solid axle. Swapping one in on the VERY off chance I might want it is a VERY small compromise to compare with the years of much nicer driving/towing experience. JMO…

As for sway, I have NO sway to speak of in the HD. That has nothing to do with IFS but is an effect of spring rate (something a Burb has very little of)and body mass over the CG (something a Burb has lots of). My tuck also has the sway bars.

 

That's why I added the fudge "(well, not quite if you want to get picky)". It's not as cut and dried, but at the time I typed it, I didn't feel like going into the detail to be fully accurate and that is sort of a nod in that direction, but, I didn't state it as fact. However, that "nod" hopefully does get people to think about the limits of what's possible with a live axle. Sure, unequal length links can account for some of it and help keep things in range, but it's no where near as dynamic as an IFS where every parameter is changing as the suspension geometry changes for optiimal toe, caster, and camber as the suspension cycles.

 

I'm not supporting the "worst suspension ever made" theory, though it does have it's problems, but I would like to mention yet again that "most" does not imply "best". And "most" is also debatable depending on how you "count".