STI cam bolt is $5, OE bolt is like $3, factory adjustment time (it gets aligned anyway so this is just additional time on the rack) call it 10 minutes of additional labor that's well below $60/hour, I'd guess it'd cost around $20 per car to have factory cam bolts installed just on the manufacturing side, on 250k cars, add in some meetings with engineers and accountants and planners arguing over the merits, a few test sessions, that's easily a >$5 million dollar change to the car which probably would have trickled down to a ~$50 price increase if it all passed along to the consumer.

Or people who care just buy $20 SPC bolts, and Subaru gets to pocket at least $5 million in savings over the life of the platform.

I wouldn't consider it without really good dampers and very specific build requirements. For most it's not necessary to go down a swaybar-less route IMO, especially up front.

- Andrew

LOL To summarize:

If you distill what has been written so far, you can see there are basically two schools of thought regarding sway bars and springs:
1. Soft springs and fat, stiff sway bars
vs.
2. Stiff springs and softer sway bars for tuning only.

Stiff sway bars and softer springs will give a smoother ride but the fat sway bars will tie the two sides of the suspension and defeat the independent suspension. Hit a bump on one side and the whole car will jump around.

Stiff springs and soft sway bars for tuning over-/under-steer, the setup I prefer, gives a "bumpier" ride but won't get as upset when you hit bumps on one side. Also, stiffer springs will keep the car from diving and motor-boating under braking and acceleration.

Which is "better"?

I don't think there is any consensus on which is better. Some people/teams prefer the former. E.g., Herb Adams, an ex-GM/Pontiac engineer who developed the F-bodies used to say there is no such thing as a too big sway bar: Firebirds used to have really huge sway bars from the factory.
Some prefer the latter. IIRC, Carroll Smith preferred springs stiff enough to keep the car off the bump stops and tuning over-/under-steer with adjustable sway bars. Back in the day, IIRC, TRD sold some really stiff springs but no sway bars. And just a side note, my 1988 Toyota pickup came with NO sway bar at all. Of course it didn't/doesn't handle worth crap at the moment (I'll be fixing that, soon)..

On a smooth race track, I'm guessing it doesn't matter.

And "best" is probably somewhere in between. So, in the end, all you can do is do a lot of research, ask around (like you did here), try different setups and figure out what YOU like best.

Oh, whichever way you go, be sure your dampers (shocks) are properly matched to your springs for your intended use. IMO, shocks affect the ride/handling more than the springs.

I don’t think slightly bigger sway bars affect independent suspension articulation as much as people think.

If the bars were connected directly the strut then yeah, but we have endlinks with ball joints on them that’ll still allow independent articulation.

Sounds like you've never seen Herb Adams' aftermarket sway bars. Something like 1-1/4 inches for F-bodies which his company specialized in. He used to say that was the largest he made only because his bender couldn't handle any thicker bars. But he was an extreme on one side of the spectrum. And he was mostly concerned about track driving. Although, watching a few races, racers like driving on the berms so such a bar would upset the chassis.

Your comment is more of a "somewhere in the middle" type of comment...

I always read about "soft spring-stiff sway" or " stiff spring-soft sway" but what about mixing the two? Let's say for example that we put 8k spring in the front with 20mm sway and 12k in the rear with stock sway...could it be that bad?
I've read that stiffer rear spring help the car settling after a bump so using the front sway to compensate while turning could be nice in theory...what do you think? Any experience?

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I run relatively large bars (22/18) on otherwise stock '13 suspension, save for alignment and camber bolts. I like in one of the worst areas of the country for road conditions. Yes, when I bumped up in size, there was a small increase in roughness associated with tying the two sides of the car together more firmly. Doesn't matter though, because the improvement in roll resistance was precisely what I was looking for. I daily my car and do an occasional track day. I'm less worried about a little straightline squat under braking than I am for maintaining compliant suspension settings. The car is already too stiff for the shite roads we have here, so I'm certainly not interested in making it harsher EVERYWHERE. And the payoff is that the improvement the bars made were really all I was looking to change in the setup. Balance stayed basically the same. The car leans less. It's still OEM-comfortable on the highway and I don't have to worry about clearance issues and reduced suspension stroke. Could I go faster on the track with a higher, linear rate spring and a better shock that has adjustable low and high speed damping so it could be tuned for individual driving conditions? Yes. I don't track for points, and I'm not leaving a lot on the table with the current setup. It's plenty quick when driven right. Swaybars are a simple and inexpensive tuning aid that make a noticeable improvement when selected correctly - nothing more or less.

Ummm... that's not how the bars work, at all. The only way to have independent wheel motion is through the bar twisting.


Take the springs off the shocks and bolt everything else up, lift one wheel and see what happens to the other.


The reason for the end links having balljoints is because it's macpherson strut and the strut rotates as you turn the wheels. There are aftermarket end links that don't have balljoints (perrin non adjustable), just big bushings at both ends that deflect when you turn the wheel.

I don't think he's disputing the obvious fact that sway bars tie both sides together to a certain degree, as they do with the factory setup. It's that going to a moderately larger bar doesn't immediately turn the suspension into a beam axle. Yes, some movement gets transmitted to the opposite side, but then again, that's how they're supposed to work in the first place.

My panties are all in a bunch over the idea that the sways could somehow be directly connected to the struts.

They ARE effectively attached directly - just by means of the link. Whether the link was there or not, it wouldn't change the fact that movement on one side transfers some of that force to the other side...the link doesn't lessen that. But the point I'm making is that this transfer of force is the fundamental idea behind how a swaybar works in the first place. Yes, making the bar stiffer will transfer more force, but increasing spring rates instead of swaybar size produces it's own equally (or arguably MORE) unappealing side effects. This car already uses sway bars. Swaybars have been in use for a really, really long time. F1 cars use sway bars. Swaybars are not a bandaid. They are a suspension component whose particular characteristics cannot be evaluated by themselves, as with ANY piece. It's an entire system of components with an extremely wide range of operating conditions, and given that range, swaybars work extremely well.

I think we're doing potato-potahto. Totally agree with you.

So basically you want to install coilovers first, see how you like the spring rate, damping or whatever and then figure out if you need front or back sway bars and whether they need to be firm or soft? Alllllrightythen

Or if all you're looking to do is reduce lean a bit, and you're otherwise fine with the existing spring rates and balance, buy a set of bars that increase the diameter uniformly and call it a day.