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Discussion Starter #1
Hey all, it's not been discussed at length here so let's discuss.

From what I can tell here are the part numbers

2014-2016 XT rear shocks: 20365SG010
2014-2016 2.5 rear shocks: 20365SG001
2014-2016 XT rear springs: 20380SG021
2014-2016 2.5 rear springs: 20380SG011 for AT, 20380SG001 for MT.

2017 XT/2.5 rear shocks: 20365SG100
2017 XT rear springs: 20380SG121
2017 2.5 rear springs: 20380SG111

2018 XT/2.5 rear shocks: 20365SG200
2018 XT rear springs: 20380SG320
2018 2.5 rear springs: 20380SG310

So, what it appears Subaru did was they were originally using two different shocks for years '14-'16 for XT and 2.5 models, along with different spring rates for XT and 2.5, with a third rate for MT models. Then in 2017 they went with a single shock for both XT and 2.5 models but still had different springs. Then for unknown reasons changed it up in 2018 and went with different shocks again, and different springs following the same approach as 2017.

However, per Mann engineering, they found 2018 shocks to be of a different design.
For 2018 Subaru Forester XXXX Models, rear shocks from a 2014-2017 model car will need to be sourced to make the springs fit correctly as there was a design change for the 2018 model year. We are recommending that rear shocks from a model year 2014-2017 Forester XXXX be used to make the springs work properly.
Now, I didn't know this when I replaced springs on my 2018. I've used RS-R and STI Pink springs. Both I did find the perch of the shock body to be slightly smaller in diameter which made the springs shift around a bit on the perch. Having had them mounted for some time I've not had any problems, but I did just check their positioning on the perch and they have moved a bit and aren't sitting centered on the perch like you'd expect if they were paired perfectly together.

I don't think it's a problem worth fretting over, personally...but I think this is information that folks should take into consideration. I'm baffled why they would have switched the design up for 2018 and why they'd go with a smaller perch and spring...yet keep the top hats and every other part of the rear shock assembly that I'm seeing to be the same as the 2017 year.



 

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which do you like better the RSR or the Pink STI springs? I saw you had the RSR for sale.

I just got a set of Pink STI Springs that I plan on installing tomorrow - I currently have BC Racing Coilovers that I want to swap out.
 

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Discussion Starter #4
which do you like better the RSR or the Pink STI springs? I saw you had the RSR for sale.

I just got a set of Pink STI Springs that I plan on installing tomorrow - I currently have BC Racing Coilovers that I want to swap out.
The RSR are firmer and tend to have more aggressive rebounding but based on these changes in dampers it's hard to say whether or not the experience is the same across model years. I wonder if the 14 to 16 XTs don't have better dampening, having XT specific shocks compared to 17 and 18s.
 

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Discussion Starter #5 (Edited)
Received some clarification from Mann regarding the differences between the 14-16 and the 17 shocks. The 17 shocks are recommended over the 14-16 as the 17 shocks have the same physical design of the earlier models but have different internal valving which matches the 18's valving.

I'm taking that to mean the 17's valving is improved for our applications compared to the 14-16.

Also, just perusing Mann's facebook page, came across this post of having installed their springs on an '18 and the G200 shocks are pictured...I think it's pretty clear here seeing the concern with the springs not centered on the perch.

 

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I went with Mann Springs on my 18 NA. I didn't want to go super low on coils as this is my DD family car. It turned out to almost be as expensive as coils because I replaced my shocks with the 17 shocks.
 

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I went with Mann Springs on my 18 NA. I didn't want to go super low on coils as this is my DD family car. It turned out to almost be as expensive as coils because I replaced my shocks with the 17 shocks.

Do they not have an '18 specific spring yet?

Hows the ride? Based on my research, the Mann springs fall between stock and the RSR as far as spring rate. Before / after pics?
 

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Discussion Starter #8
I took the opportunity to replace the 200 shocks with the 100 shocks from a '17 and the springs definitely were moving around a lot on the perch of the 200 shock body. The strut base you see in my first picture that shows a little marking on it from the spring rubbing was now showing bare metal all around the base so the springs were moving in every direction.

New shocks feel a hair softer but that may just be my imagination or them breaking in. I do think it's a good idea for any '18 owners with springs to consider buying the 100 bodies. I got them both for $186 shipped from Subaru Online Parts so not a particularly pricey swap.
 

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Honestly, the 2018 are probably are a new design shared with other cars with similar shocks. It would be interesting to compare the current crosstrek, forester and outback. Although, I suspect their part numbers will not match due to application specific shock tune.

For example, I am running SJ struts front and rear on my SH for better valving using king springs and there are some subtle design differences between the two generations of shocks but they are basically interchangeable. KYB was able to provide me with a little more info on dyno rates in my research, see the pic in my thread. https://www.subaruforester.org/vbulletin/f242/sj-struts-shocks-do-work-sh-2011-sti-control-arms-fit-781873/

Also, it seems that KYB does not have a replacement shock for the 2018 forester yet.
 

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Hey, Scooby24, I also have a 2018 XT and am planning on installing Swift 4F913 lowering springs on SG100 (2017 XT struts) on my 2018 XT. The Swift drop is -1.5" F/R and as camber is not adjustable in the rear, do you know what the camber was in the rear with the RSR-Downs? Since these lower the ride height -1.6" the drop is comparable to the Swifts.

Also would appreciate feedback from anyone with a lowered 2018 XT that has installed toe-link adjustment or camber correction trailing arms or the Whiteline camber adjustable top bushings in order to correct the camber to stock settings. Were you able to set the camber and toe back to factory settings?

Appreciate feedback from anyone that has Swift Lowering springs on an SJ XT.

I can't find the stock spring rate for the 2018 XT springs. IIRC Subaru increased the spring rate by 10% front and 20% rear over the 2017 MY. Can anyone confirm this?

Thanks for any help with this,

Bez
 

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Discussion Starter #12
The rear camber will be a bit more negative but it's not so much to be visibly noticeable. I think mine was around -1.6 to -1.8 degrees in the rear.

I had camber adjustable rear control arms. SPC ones to be exact. I got rid of them after I kept having alignment issues. They would get aligned okay on the rack but there was a bit of a dead spot with the camber adjustment bolt where it needed to be so it would slip a bit after the alignment and throw off the camber which in the rear also threw off the toe and ended up with an additional 1/32nd more wear on one tire in particular. Not worth it for that setup.
 

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The rear camber will be a bit more negative but it's not so much to be visibly noticeable. I think mine was around -1.6 to -1.8 degrees in the rear.

I had camber adjustable rear control arms. SPC ones to be exact. I got rid of them after I kept having alignment issues. They would get aligned okay on the rack but there was a bit of a dead spot with the camber adjustment bolt where it needed to be so it would slip a bit after the alignment and throw off the camber which in the rear also threw off the toe and ended up with an additional 1/32nd more wear on one tire in particular. Not worth it for that setup.
Thanks for your input Scooby24. I was hoping to be able to avoid having adjustable lower control arms. I had H&R springs on a 2006 Legacy GT that dropped the car 1.5" and had no issues with tire wear over the life of the tires but did rotate them regularly.
 
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