OK, baseline > '12 Boss already running 5300-T springs with stock bars and everything.

Got new sway bar end links because why not?! And because I've never had a mustang that I didn't bend the stock end links on. Out installing the new Steeda end links and something was just off about getting them set up. Turns out, it's the factory bonding to the bushings. No big deal, I just happen to have a set of correct front bushing from another kit I can install. So, I have the stock bar out and ready to strip off the old, bonded bushings.

Good, correct call for setting up a sway bar, correct??

Second thought; since it's apart, why not just pop in a new 5490-A sway bar set? but then I got to thinking, the 5490 and the stock sway bar are the same size. Only benefit would be the adjustability, which I currently think is beyond my capabilities and/or usage.

Is there any benefit from going down in size in the rear (26mm down to 22mm in the 5490)?? I suppose the new end links/bushings would make for a descent upgrade? AND, since the LS is built around the 26mm bar, is it accurate to say you could use a stiffer setting on the 22mm bar to account for the smaller size, if so desired?

Thoughts on any or all of my logic? Strip down the stock bar and reuse? F$%& it and get the 5490? (remove money & logic from your equation, lol).

And disregard my comments about the rear bar as it is not adjustable.

Most of the track guys on TMO will tell you that the best way to take advantage of a solid rear axle Mustang's strengths is to maximize traction coming out of a corner exit so you can put the power down. To do that they most often recommend either no rear bar at all or a very small rear bar.

But for a street car -- you might have different priorities. When I tried this on my car (Steeda Boss springs and Koni yellows) I found the rear end to feel floaty and understeer to be a little much. On a track car I think you'd adjust for this with spring rates... I tried the V6 bar too, but I ended up putting a slightly smaller GT bar on my Boss. IMO the stock GT bar works well for a square tire street setup on the S197. I think the Boss increased the size of the rear bar to offset the understeer caused by the staggered tire setup.

I think the best answer is it depends on what you want to do with the car, and what it's other current specs are like spring rates, tire sizes, etc. My car is a daily and I can't track it right now -- so I outfit it with what feels good for a fun daily. But generally the serious track cars on TMO run no rear bar or a tiny rear bar.

Here's a chart I like to use for what various mods do to oversteer/understeer:

Rule of thumb: Increase rear traction relative to front traction, increase understeer. Increase front traction relative to rear traction, increase oversteer.
More rear bar reduces rear traction (cornering) in order to reduce body roll. Less rear bar increases rear traction but comes with more body roll.

Weeelllll, after a low turnout on this thread, and tons of research (that started long before I made this post), I decided to get the 5490-A sway bar kit for the LS. Worst possible thing that could happen is what, don't like the rear?? I'm thinking with the stiffer than stock rear springs, the softer rear bar would balance out more than hurt anything. And the front being the same 35mm size, it's a wash. If anything, I gain some adjustability. Plus it's blue to match my springs and shocks, lol. I just didn't feel like tackling off the bonded stock bushings, which I considered mandatory with the lower springs and new end links. Oh well.

Sorry for the slow response, I think @BackInBlack hit it about right. What do mean you didn’t take off the bonded stock bushings? Are you talking about the front bar? I think Ford did that to avoid squeaking or something. I didn’t like how it at least theoretically affects the overall wheel rate, but I don’t know how much that math actually works out to be. Just get rid of it.

22 mm rear is a step in the right direction but smaller is better imo. Now you know how easy it is to swap out the rear, try just taking it off completely and see how you like it.

Basically, the more you can isolate the left and right rear wheels impacts and movements from each other, the more composed the rear will be on bumpy surfaces. A simple way to do this is a smaller or no rear bar. A second more expensive but still easy way is by using true rear coilovers which place the springs further outboard.

The dynamic in this video is what we’re trying to reduce:


The common misperception is that the problem is inevitable because the axle is solid, which may be true to a degree but you can improve it greatly with the mods we’re discussing here.

In all of this make sure you have rear shocks with plenty of rebound damping. Our SRA have a ton of unsprung weight- in fact that’s probably the bigger challenge than the fact that it’s solid - and it’s important to get that weight under control as much as possible when you hit a bump. You want a one and done up and down movement, not bounce bounce bounce.

EDIT, you may find this old thread interesting. I’ve come to more fully appreciate the effect of rear sway bar sizing in this discussion. https://trackmustangsonline.com/threads/true-rear-coilover-daily-ride-and-handling-comparison.16874/

stevbd said:

What do mean you didn’t take off the bonded stock bushings? Are you talking about the front bar?

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Hey, thanks for the feedback. Yes, the bonded bushing on the front bar. I was in the process of removing those before I decided to go new. At ground level, I had to apply pressure (resistance from the bonded bushing) to get the stock end links back in. And my new adjustable end links were not long enough to fit the stock bar if I let the bar sit freely with no preload on the stock bushings. I know enough to know that’s not right. Thus removing the stock bonded bushing from the stock bar. That’s when I said f’ it, and just bought the new set, lol.

That's a good video. There's a couple other good points in the full video.
1. An advantage the stick axle has:
2. How to mitigate the problem:

Well yes but we’re talking about mitigating the skip with setup not counter steer. If you’re counter steering through the corner you’re probably losing time. I think it’s interesting that in that video the car has an upsized rear sway bar.

BackInBlack said:

That's a good video. There's a couple other good points in the full video.
1. An advantage the stick axle has:

2. How to mitigate the problem:

Click to expand...

These guys literally do not know what they're taking about. They will produce these really impressive videos describing car handling all sorts of wrong. They know a selection of words, but those words have different meanings than they suspect.

TeeLew said:

These guys literally do not know what they're taking about. They will produce these really impressive videos describing car handling all sorts of wrong. They know a selection of words, but those words have different meanings than they suspect.

Click to expand...

I don’t know much about that whole channel but agree with you there is a lot of unhelpful misinformation or at least incomplete info in that video. I only posted it for the actual video picture going over the curb, not the commentary. I should’ve been more clear sorry.

stevbd said:

I don’t know much about that whole channel but agree with you there is a lot of unhelpful misinformation or at least incomplete info in that video. I only posted it for the actual video picture going over the curb, not the commentary. I should’ve been more clear sorry.

Click to expand...

I'm not slagging you. They have interesting things that they cover and it has the potential to be a decent source of information, but the explanations and conclusions can be wrong to the point of bizarre. They do have a couple million people watching it, so they're doing something right.

Got the rear on. The brackets are a pretty nice upgrade over stock rubber kit. I’m still thinking the smaller bar will be a wash at worst, improvement at best, and worth it for the hardware upgrade…and the blue

Interesting about the front bar; both 35mm, identical shape, but the factory bar is noticeably lighter. Wall thickness? Material?

galaxy said:

Interesting about the front bar; both 35mm, identical shape, but the factory bar is noticeably lighter. Wall thickness? Material?

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Wall thickness. Steel alloys all weigh nearly the same. Now if you had sway bars made of titanium vs tungsten...

galaxy said:

Got the rear on. The brackets are a pretty nice upgrade over stock rubber kit. I’m still thinking the smaller bar will be a wash at worst, improvement at best, and worth it for the hardware upgrade…and the blue

Interesting about the front bar; both 35mm, identical shape, but the factory bar is noticeably lighter. Wall thickness? Material?

View attachment 112130

View attachment 112131

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Nice start, now go smaller.

Dayum, your car is immaculate. I’m jealous!

stevbd said:

Nice start, now go smaller.

Dayum, your car is immaculate. I’m jealous!

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LOL...I keep learning this is the way. I am no where near an expert on over/under steer, and still running staggered (but sticky) sizes, so maybe not too small (not too much understeer) is a good thing???

Thanks! Detailing is my life! But on this one, I can't take all the credit; it's a brand new car

Dave_W said:

Wall thickness. Steel alloys all weigh nearly the same. Now if you had sway bars made of titanium vs tungsten...

Click to expand...

Go carbon or go home, lol!