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I just completed the 19mm sway bar modification. I know this mod has been mentioned in another thread, however I think it would be useful to have its own thread to consolidate all the info out there for those who are considering doing it.

I’ll aim this post at someone like myself who rarely works on cars but has a basic tool knowledge that goes a little beyond righty-tighty, lefty-loosey, but is also a little intimidated by the thought of “ripping apart” a brand new car whose suspension is really very adequate as is. I’m completely A.R . about knowing exactly what is the correct way to do something and using the proper tools to do it. I spent hours researching all the threads I could find on Subaru forums, as well as researching other issues and questions that arose as a result of that effort. The most helpful info I found was on this forum:

http://www.subaruoutback.org/forums/104-gen-4-2010-2014/24867-sway-bar-mod-picture-tutorial-7.html

First of all, why do it? I’m actually still not sure exactly why. It’s my understanding that the stiffer 19mm bar will essentially enable the back of the car to follow the front of the car in a more responsive way than the OEM 16mm sway bar and should reduce the rolling feeling in sharper turns. I liked the feel of the original suspension but was curious what difference it might make. The bar runs the length of the rear axle and connects the left and right side suspension assemblies together. My concern was that I would trade up to crisper handling at the expense of a harsher ride. That concern turned out to be totally unfounded.

Secondly, how hard is it and what tools and experience level do I need? Big picture, it’s ridiculously simple. You’re essentially undoing 6 bolts, swapping out the OEM bar for the 19mm bar, and re-tightening the bolts {on a new car with no rust you could probably get away with any kind of a 12mm and 14mm wrench (or rachet) as a bare minimum, but more on tools later}. The bar is a long rod running underneath the back with a 90 degree forward bend in each end. The ends are attached by a 14mm bolt to the upper end of a short vertical piece about 4” long called an endlink. The lower end of the endlink is attached to the lower control arm on the rear suspension. The bar itself is bolted onto the car frame at each end by a C-shaped clamp with 2 12mm bolts at the top and bottom of the clamp. The clamp holds a 1” wide bushing which encases the bar. It took me about 2 hours because I took my time and looked around underneath and thought it through so that I wouldn’t find myself undoing something I couldn’t put back together. If I did it again I could easily do it in under 1/2 hour. The most time-consuming thing would be using Goo Gone to remove the part sticker that peels off in microscopic pieces.

So how do you do it? Here is where it gets a little not-so-simple because I read a lot of conflicting advice, but here is the sum total of what I could glean.

1. First position the car properly. Everything I read suggested that this install should be done with the suspension loaded (ie. weight on the wheels). Right away I got confused because the Subaru recommended procedure for the install has removing the wheels as the first step. I modified their procedure and left the wheels on as most people seem to do. Also, you could probably scoot underneath in a pinch, but it becomes a whole lot easier to raise the back end on ramps or jack it up and lower it onto wheel cradles. I used Race Ramps RR-30 Rally Ramps and they were perfect:

http://www.amazon.com/gp/product/B00H5PTQIU/ref=oh_aui_detailpage_o03_s01?ie=UTF8&psc=1

I hate trusting my life to a single point of failure so in addition to using ramps with the parking brake set, I also positioned backup jack stands and chocked the wheels.

2. To remove the bar, I first disconnected the 14mm endlink attachment. This bolt has a smooth flat end on the outside end facing the tire, and the other inside end has a hex cutout in the bolt end that accepts a 5mm allen wrench. On a new car you could probably get it loosened with a 14mm rachet or wrench and spin it free by hand. If the bolts are rusted or stubborn, once the bolt is initially loosened it may spin with the wrench, so it would need to be held on the same end as your 14mm wrench by a 5mm allen wrench inserted in the bolt end. The ideal setup is a ratcheting 14mm boxend wrench on the nut with a 5mm allen wrench on the same bolt end, but you could probably figure out a way to coax it out using less orthodox methods.

Next you simply loosen and remove the 4 12mm bolts holding on the 2 bushing clamps. Don’t worry about it falling - even with the endlink bolt nuts removed the bar is still held in place until you maneuver it off the bolts. Make a note when you remove the bushing clamps that they are also secured at the top by a hook that goes through a small hole in the bushing mounting plate.

3. To install the new bar, most people have been using this Subaru part:

Subaru Outback Rear 19MM Sway Bar Kit (Part No: 20451FG020-20464FG020 x2)

You have to first position the two bushings on the bar - there is a split in the rubber that opens to fit it over the bar. The kit comes with instructions on where to position them but big picture there’s really only one place that they can go and it’s pretty obvious if you look at the original bar. The bushings that come with the 19mm kit are stamped “18”, and the bushings on the 16mm OEM bar are stamped “15”. It all works, so go figure...

I first loosely installed the 14mm endlink bolts, and then lightly bolted on the 12mm bushing clamps to make sure the bushings were centered properly. Then I snugged down the endlink bolts a little on each side at a time until they were pretty tight. Then I used a torque wrench and tightened to spec (14mm bolt is 24.3 ft-lb). This is where having the rear end raised on ramps is really nice to accommodate the extra shaft length of a torque wrench. Then I torqued the 12mm clamp bolts to spec (28.0 ft-lb). That’s all there is to it!

So here are some questions and “tips” that I came across to muddy the waters.

1. Will this void the warranty? PROBABLY NOT given that it is a Subaru part. It would have to be shown that the install caused some problem. Consensus has it that a Subaru mechanic wouldn’t even notice the difference with a casual glance. If you use an aftermarket brand then I don’t know.

2. Will the stiffer bar require a “beefier” endlink? Apparently not.

3. Should you lube the bushings? The original bushings show no indication of a lubricant. They are made of softer rubber and work fine by themselves. Aftermarket poly bushings are made of a harder material that will eventually squeak if not lubricated.

4. Should you use locktight or some kind of lubricant on the bolts? The original bolts show no evidence of this.

I learned a lot about torque. Torque specs are based on “dry” hardware. If there is anything that eases the way the parts move during tightening (eg locktite, anti-seize, etc) you can actually overtorque a bolt to the point of snapping it off. Don’t overthink it - I wiped my bolts dry and torqued them down just fine. You could probably get away with the backyard mechanic special of tight plus one more push for good measure. I also learned that a torque wrench should be calibrated and stored with the torque at the lowest setting. I pitched my 20-year-old wrench that had sat forever with the torque at a high setting and got a new one.

When all was said and done, I honestly can’t discern a noticeable difference in handling, but I sure had fun doing it. It did track straight as an arrow through a wicked crosswind the other day. If anyone can correct anything I said please chime in because I’m by no means an expert.
 

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Good write up! Like you said, it has been covered in depth other places, but you did a great job of summarizing it all.

A few things I would like to mention:
1. The 20mm STI rear sway bar is also an option, and is cheaper. Currently out of stock, but will be back in stock soon.
Subaru XV Crosstrek Rear Sway Bar Kit - 20mm (Part No: 20451VA000-20464VA000 x2)
(This kit WILL work on the Outback, both 2010-2014 generation, and the 2015. There is also a kit that says it's for the Forester. Same parts. They will work.)

2. If you currently have a 2010-2014 Outback and are contemplating a '15, your 19mm sway bar will carry over.


To answer your questions:

1. If you were to have an endlink fail, and try to claim it under warranty, I doubt Subaru would give you a new one for free. but you might get lucky.

2. It has been documented that the stock end links CAN fail using a 19mm bay, but I think the vast majority of users (myself included) are still using OEM links. the Kartboy end links have been using with good success.

3. A little grease never hurt anything. But probably not necesary unless it's making a noticable noise.

4. I think proper torque is more important. Check them again in a few weeks to make sure everything is still snug.
 

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Thanks for the write up! In my opinion there is no need to put the car on wheel ramps. The OB is high enough that you can access everything by scooting underneath, which I would recommend doing.
 

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I replaced the front and rear sway bars on my 2001 4runner and there was a huge difference (both diameters increased by 1/4").

My thought process was this: 3" suspension lift + 1" body lift + 33.5" tires placed the cog much higher. Reducing the body roll would make for a much more confidence inspiring on-road driving experience. The trade off would be slightly less wheel travel and stiffer ride off-road.

The reality: On-road performance was greatly improved. The rig felt much more stable and responsive. The off-road experience was awful. The ride, especially on washboard or repeated bumps, was so harsh that I needed to install sway bar disconnects. My back and kidneys hurt after the shortest rides. Once the sway bars were disengaged though, it was like riding on a cloud.

I am certainly not saying this will be your experience with the Outback. It is very important that you keep in mind how you will be using the vehicle. If it is 80-100% pavement, then the sway bar swap is probably a great way to go. If you like to take your Outback out back, then the factory bar is probably the best compromise between on and off-road performance.

Just my .02 and experience.
 

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I can't imagine what the 20mm would bring to the table that this 19mm doesn't have.

I very much enjoy the more responsive steering and cornering.

It puts a smile on my face - I installed mine by just crawling under there and pulling off the old and installing the new.

23 minutes buttoned up and test driven.

...awesome mod...
 

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I can't imagine what the 20mm would bring to the table that this 19mm doesn't have.
The 20mm bar should be about 23% stiffer in torsion than the 19mm bar. (FWIW, the torsional stiffness of a solid or tubular shaft is generally proportional to the 4th power of its diameter.)

Assuming that the OEM stabilizer bar is 16mm, a 19mm bar should be 99% stiffer, and a 20mm bar should be 144% stiffer. A small increase in diameter yields a much greater increase in stiffness.
 

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Seaton: I put a 19 mm Rallitek on my 2010 & found the same change in dynamic as you did w the 19 mm - helps with turn in & small radius turns, not so much with sweepers.

I assume you are getting the Subie VX Cross Trek 20 mm bar, correct?
What did your RT end links cost? Did they complicate the install I any way?

I have 20 mm VX bar on order for my 2015 2.5i (also on order) so I look forward to your report.

Thanks Seaton & PI134!
 

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For me, the initial turn is flatter and the car will hold the line better. However, over long sweeping turns I find that it is not enough and the car will want to understeer about as much as it did before the upgrade. This the reason I am upgrading the endlinks before putting on the 20 MM bar. The stock endlinks are very flimsy and you can easily push them away from the bar with your hands when installing the bar. The new endlinks that I ordered are about 30 percent large diameter and include poly bushings.
Thanks.

So what's the potential downside, if not harsher ride? Tiny increase in the potential for the rear to come around in slippery conditions?
 

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So what's the potential downside, if not harsher ride? Tiny increase in the potential for the rear to come around in slippery conditions?
For most vehicles, the effect of a stiffer rear stabilizer bar is to reduce understeer/increase oversteer. Since most suspension designs have a lot of understeer to start with (for high stability margins), the practical effect of a stiffer rear stabilizer bar is usually more neutral cornering behavior.

I suspect (but do not know) that a too-stiff rear stabilizer bar on a Legacy or Outback may eventually interact ... perhaps adversely ... with the electronic Vehicle Dynamics Control (VDC) system, since the control logic has to assume OEM roll stiffness, front and rear.

For me, the initial turn is flatter and the car will hold the line better. However, over long sweeping turns I find that it is not enough and the car will want to understeer about as much as it did before the upgrade.
This may (or may not) be anecdotal evidence of the VDC system "fighting" the stiffer rear stabilizer bar under higher-performance cornering conditions.
 

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Good to know, keep us posted with your findings.
Do you have any impression that the PU bushings in Rallitek endlinks has affected the ride or noise vs the rubber bushings of OEM?
 

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The stiffer poly bushings have undoubtedly firmed up the ride over the soft rubber in the stock bushings. There is a little more road noise transmitted to the cabin, but not anything that I found offensive.

After driving a little more last night, my current plan is to stick with the 19 MM bar and order some poly bushings for it. I may then add the GT Spec braces. I think the 20 MM bar with the endlinks will be too much.
Can you put up a link to the poly bushings & end links you've bought and the bushings you are considering for the 19mm bar?

thanks
 

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After driving a little more last night, my current plan is to stick with the 19 MM bar and order some poly bushings for it. I may then add the GT Spec braces. I think the 20 MM bar with the endlinks will be too much.
Thanks for being our Beta tester here. Now you got me worried... What do you mean by "I think the 20 mm bar will be too much. "
Do you plan to cancel your order for the 20 mm bar or are you going to put it on to compare? I would love to hear the comparison.
 

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19 mm sway bar

Great info in this thread. Hope to hear reports from even more experimenters.

Our 2015 OB is only a couple weeks old, so the wife may not want me to mess with it yet. :)

Curious to hear about other elements that need to upgrade at the same time. Was about to order 19mm, then saw the comments about rubber vs. poly bushings. I definitely don't want vibration or road noise from harder bushings.

Will keep listening for latest recommendations! thanks
 

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Wow, fast response Seaton, thanks!

Without upgrading the end links and without getting poly bushings (i.e. just order from link below), do you think it will be noticeably better, or just placebo effect :)

Any concerns in terms of safety by not upgrading the end links at the same time? From the 2014 threads, there didn't seem to be much concern.

Subaru Outback Rear 19MM Sway Bar Kit (Part No: 20451FG020-20464FG020 x2)
 

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The concern I have with the 20 MM bar is the likelihood for wheel hop (i.e., the tendency of the rear wheels to step out after hiting a bump in a corner) without upgrading the rear shocks to something with greater rebound. AFAIK there are no aftermarket shock options for the '15s yet, so I did not want to go there.
There is so much flex everywhere else in the car (suspension components, massive sidewalls, chassis flex, etc...) that I don't think the 20mm will come close to causing this. Someone installed a 22mm Whiteline bar on their car and hasn't reported any issues like this yet.
 
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