Review: Bilstein BTS5056J / BTS5058J Suspension

What is this review about?

 

Let's face it, the 05-09 Subaru Outback is not a great handling machine. In fact, it can be downright dangerous when the rear shocks wear out (typically at 60k+ miles) along with the rubber bushings tearing in the rear suspension's front and rear lateral links. A large thread on the subject is here, and a good summary is quoted here:

I traced the OB problem to suspension geometry. You have a suspension that is basically more then functional in the legacy. You jack it up and even with the body spacers you are way beyond the center point of it's travel. Add under-dampened struts and the rear will bounce up and down. As it is bouncing the rear toe is going + and - drastically. So the rear starts to go side to side as the tires, which are each going different directions, fight for control. Add the relatively light weight of the rear and it just does weird things. The whole rear is a bad compromise to a market request.

 

That is why it is so apparent in the slalom. The rear tires are going different directions. As you are loading the outside rear tire in a turn, the toe is changing and you get a very non-linear feel. Then you shift the weight back to both tires and you again get that non-linear "what was that" feeling from the rear.

 

Over at Subaruoutback.org a guy was able to add weight while the car was still on the alignment machine. If I remember right, a 1/4" of compression yielded over 1/2 degree of toe change and it was not linear so it just got worse with more compression. You wouldn't expect it to be linear anyway with the suspension being artificially "centered" towards one limit of it's stroke.

 

My solution was to limit the travel of the rear. Less travel is less toe changes. I have OB struts with Legacy wagon springs and a RSB. That's my story and I am sticking to it.....

This review discusses my thoughts on various suspension options and how they behave. In particular, I look at the JDM-market Bilstein BTS5056J and BTS5058j kit composed of tuned struts and springs, and compare them to the KYB suspension on stock Outback springs. For a lot more info on the BTS setup, you may want to start with Mike Schneider's epic thread here. He was a true pioneer for testing out the kit.

 

 

About the reviewer

 

I try to be thrifty and search out cost effective solutions. Primarily due to saving money, I do all my own repair work and buy private sale vehicles. I take pride in not exaggerating the benefit of mods, and I understand how mods don't always make a car better. Often, as I've learned from experience, mods typically involve trade-offs that may work well for one person but not for another.

 

Do I know how to drive? Does my opinion on handling have any credibility? Not really. I'm a performance driving novice, having only done the following in my old BMW E36 M3:

--5 Autox events

--1 HPDE (Watkins Glen, NY)

 

4th Gen Subaru Legacy's I've previously owned:

2008 Legacy 2.5i

-- Bought car at 50k

-- Used OE struts up to 90k

-- KYB replacements to 100k

2008 Legacy GT (bought it on the forum here)

-- RCE Tarmac 1 coilovers for 35k

-- KYB replacements for 2k

-- Significant suspension mods: tons of poly bushings, F+R sway bars, roll center kit, etc

 

Current Subaru stable:

2008 3.0R Limited sedan

-- OE Spec B Bilsteins with 110k miles

2009 Subaru Outback 3.0R

-- OE struts until 106k

-- 3rd Gen F+R KYBs until 108k

-- Bilstein BTS5058j until 109k

 

 

Parts List

 

The following is everything you need to have a drop-in strut replacement without having to swap over spring perches, top hats, etc.

 

Primary kit:

BTS5056J: https://www.japanparts.com/parts/detail/29564 ($1500)

or

BTS5058J: https://www.japanparts.com/parts/detail/22314 ($1600)

 

Supporting components:

Front:

SpecB top hats (20320AG01A) (qty 2) ($160, Ebay)

SpecB dust cap (20326AG000) (qty 2) ($19, Ebay)

Spring Perch/Insulator (20323AG00B) (qty 2) ($82, Ebay)

 

Rear:

JDM rear shock perch (20370AG010) (qty 2) ($38, partsouq.com)

JDM rear rubber upper (20375AE011) (qty 2) ($15, partsouq.com)

 

Total cost: $1990 including $42 customs charge for BTS kit. Not including alignment. Assumes you assemble it all and install yourself.

 

 

The Review

 

Current Outback configuration:

-- BTS rear struts at "middle" adjustment point

-- Whiteline adjustable RSB set to "mild", AVO brackets

-- All else stock and original, 108k miles

 

I bought an '09 Outback 3.0R earlier this year (Spring, 2016). I was immediately concerned about the poor handling on the highway. The vehicle was bouncing all over in a way I've never seen. I quickly found the Ghostwalking thread and I knew it must have been blown rear struts. After 100+ pages of reading, I couldn't decide what to do. Should I lower my Outback? Should I just stick with KYBs? I loved everything else about the 3.0R Outback, so maybe I should just spend the $ and get the best struts and springs available?

 

So I decided to go a little crazy. I placed my JapanParts order for the BTS kit, and it had a 6-8 week lead time. In the mean-time, I figured it would be smart to get some fresh KYBs on the vehicle for comparison. If I ever sold the vehicle, I could always go back to the KYBs and sell the BTS kit.

 

Here's a quick summary of how each setup handled on a scale of 1 to 10, with 10 being the best. This is very subjective and based on my personal experience with each! "Comfort" refers to how potholes feel. "Slalom" is how well the body is controlled during quick transitions (i.e. accident avoidance). "Highway" is how well composed the chassis is at higher speeds and during situations you often see on the highway: asphalt seems, sweeping turns, lane changes, etc. "Overall" is just how I felt about the setup overall.

 

Blown OE struts with 100k:

Comfort: 3

Slalom: 2

Highway: 2

Overall: 3

 

Fresh KYBs:

Comfort: 7

Slalom: 4

Highway: 6

Overall: 6

 

Fresh KYBs with RSB:

Comfort: 7

Slalom: 5

Highway: 7

Overall: 7

 

BTS kit with RSB:

Comfort: 8

Slalom: 7

Highway: 8

Overall: 8

 

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For Comparison sake:

3.0R Limited sedan with 110k miles (stock Bilsteins)

Comfort: 6

Slalom: 8

Highway: 8

Overall: 8

LGT sedan with RCE Tarmac 1's, FSB, RSB:

Comfort: 4

Slalom: 10

Highway: 9

Overall: 8

 

The sedans have a significant advantage from the lower ride height. They do have less comfort, but significantly better dynamic behavior.

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If I wanted to go on a road trip or camping, the Outback with BTS would be my first choice. It's so very comfortable, and handles pretty well for most things. In times where you aren't pretending to be Speed Racer, it's offers great compromise. For the guys doing Autox, you don't want to be in an Outback at stock height and the BTS kit doesn't change that.

 

So what does the BTS kit really do better than the KYBs? It excels in one big area: The roly poly bounciness prevalent in the KYBs is reduced (aka Tahoe effect). Jogging the steering wheel quickly at highway speeds results in only a little lateral body motion. There is still some but it's quite a bit less than the KYBs. This makes highway driving more enjoyable. The second noticeable thing is the smoothness over potholes and pavement transitions. I was expecting a BTS (Bilstein Tuned Suspension) to be a harsher, "sportier" ride but it's really not. It's not sporty at all. It's no sportier than my parent's VW Passat or BMW X5. There is nothing harsh about the BTS kit, and the smoothness really impressed me. It's even a little smoother than the KYBs.

 

So there you have it. The BTS kit isn't a magical unicorn. It won't transform a stock height Outback into a different vehicle. The laws of physics still apply no matter how much the suspension costs. But for certain people it's a great solution. Those people are the ones who want to stay at stock height, and want the absolute best overall ride that you can get. Obviously, this is not for those on a tight budget.

 

 

FAQs

 

Q: If you could do it all over, would you buy the BTS kit again?

A: No. I wouldn't buy it on a 7 year old vehicle worth $9k. I think M. Schneider made a great choice buying them early in his vehicle's life. If you invest in this kit, you want to do it for the long-term. When I bought this kit, I didn't know how decent fresh KYBs would be. Right before I installed the kit, I tried KYBs just for an experiment and I was pleasantly surprised. The KYBs were only around $220 after rebate.

 

Q: Overall, how much better is the BTS kit than the KYBs?

A: My opinion is that they are about 20% better all around. The cost is pretty steep to get this 20% improvement, which is why I probably wouldn't buy them again. A stock Outback feels like a Tahoe. The BTS kit makes it feel more like a regular car than a body-on-frame SUV. Yeah, that is a pretty bad insult to compare an Outback to a Tahoe.

 

Q: Is this the best handling kit that maintains the stock Outback height?

A: Yes. The market is pretty limited. You can get KYBs and overload springs (i.e. Rallitek or King Springs), depending on your needs. If you carry a lot of weight, then the overload springs are good. If you ride empty most of the time, then the stock springs are probably the better choice.

 

Q: How does the BTS kit handle carrying a lot of weight?

A: The springs are pretty soft and comfortable, but the strut seems to dampen heavier weights just fine. A fault of the KYBs on stock springs seems to be extra bounciness and sag. The BTS kit rides pretty smooth without any bounciness under load.

 

Q: Does the BTS kit handle like a Spec B sedan (or 3.0R Limited)?

A: Nope. The sedan handles better from a sportiness standpoint. The Outback's higher center of gravity and taller sidewall tire are penalties that a high quality Bilstein strut simply can't fix. However, from the comfort standpoint, the BTS kit on an Outback is more comfortable.

 

Q: How does the BTS kit handle at highway speeds?

A: Excellent. The vehicle body stays in control over highway ruts better than the KYB setup.

 

Q: Why didn't I just lower it?

A: I wanted comfort and the ride height.

 

Q: Should I lower my Outback?

A: You should lower your Outback if you want to maximize it's performance handling, and you don't care about the ride height. I suspect that an LGT wagon suspension will provide a flatter and more controlled ride than the BTS kit. There are a ton of performance options at the non-Outback height that will handle much better from a performance standpoint.

Now if only I can find the outback of my choice.

Thanks for the detailed review Dispatch. When you mention the middle adjustment on the bts kit, what adjustment are you referring to?

The rear shocks have a large snap ring that can fit into a number of grooves on the shock. The metal spring perch slides down and rests on the snap ring. So the adjustment essentially changes where the spring perch is. I attached a picture from a Supra Bilstein, but it looks the same as the BTS ones.

 

And here's a video of a truck application:

 

Nearly all non-Subaru people seem say this is simply to adjust height. However, a couple of Subaru BTS people believe that setting the ride height higher also has a side effect of either pre-loading the spring which makes it ride firmer, or putting the strut into a different range of motion (rod extension length) leading to firmer damping.

 

My personal opinion is that this is probably only a height adjustment. My theory is that the resting weight of the vehicle compresses the spring well below the point where the strut rod extension is limited (leading to no pre-load on the spring). If the struts were at full rod extension (causing a spring pre-load) when the car was sitting on them, you'd be rebounding into the rod extension bump stop every time you went over a large bump. It seems like the Bilstein strut is able to have a full range of travel regardless of the snap ring height position, which leads me to believe the net result is just a height adjustment of the rear of the vehicle. This assumes that the Bilstein strut provides the same damping at all 3 ride height snap ring locations, which is a big assumption. Bilstein never says if the damping is the same regardless of the rod extension length.

 

It's hard to be certain about any of this.

I can't remember if the included documentation said anything about what that adjustment did. I'm moving soon so mine is packed up somewhere.

I can't remember if the included documentation said anything about what that adjustment did. I'm moving soon so mine is packed up somewhere.

If it did, it wasn't in English. I looked all over the insert sheets that were included.

If it did, it wasn't in English. I looked all over the insert sheets that were included.

 

Understood, but that's where Google Translate App's camera ability comes into play.

The JDM Bilstein BTS kit is expensive, real expensive.

 

If not for the thorough suspension solution brought on by our BTS kit install .... this OB XT would have been long gone. The OB XT suspensions competency deficit is disgraceful. Any thought on the part of Subaru America to uprating the 250hp/250 XT's models suspension components escaped them. Disgraceful. WTF !

 

During the USA Outback XT production years MY05 thru '09, say years 2005 and 2006 the available aftermarket struts/shocks we're slim to none. Sure,, the OEM KYB units were available (Subaru dealership network) however nothing from the aftermarket, not KYB, not Monroe or others. The OB XT applications unique uber-raised ride-height fitment slowed aftermarket offerings. Sure,,, at the time there were several coilover mouse traps offerings on the scene - but,,, nada-zip-nada,,, for the likes of any Heavy Duty or Performance oriented strut/damper units.

 

In later production years the applications aftermarket offerings had finally emerged. The likes of Monroe and others, even the OEM supplier (KYB) joined the aftermarket offerings with units said to exhibit a 10% to 15% greater damping performance over that of the stock OEM KYB built units. Do the KYB aftermarket units and OEM units truly differentiate? I dunno, sounds like Solid Gold marketing lingo .... to this ENG's ears.

 

Along comes MY2008 with Bilstein Japan's thoroughly engineered suspension solution for the Outback XT application. A kit consisting of 4 progressive rate coil springs (maintaining the vehicles signature raised ride height) mated to 4 Gas pressure inverted monotube dampers; BTS 5056J suspension kit ..... Hallelujah! .. Bring money, bring Yen.

 

Optionally, add uprated F & R sway bars, HD drop links... "Shaken, not stirred" and your Outback XT is in business for the duration.

 

 

 

[/i]

Well said.

I believe the shocks and the struts are the same between the LGT sedan/wagon and the Outback 3.0R sedan and wagons.

With that said why couldn't you buy the Bilstein shocks and struts for the LGT and put them on the car using the stock Outback 3.0R springs?

 

https://www.amazon.com/dp/B01E4BT2TA/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=3JN5GCJ85UEM7&coliid=I2WK9ZF1A59M3F

The shocks and struts are different lengths. Most of the lift comes from the longer struts / shocks. With a little from the springs.

There is still a slight difference in height between LGT and OB springs - I remeber comparing them and its about 1" difference in the front springs and 1/2" difference in the rear springs.

My new KYB OB struts with LGT wagon springs lowered the front 1 1/8" and the rear 7/8". I have the H6 in the OB.

 

Peace,

 

Greg

With that said why couldn't you buy the Bilstein shocks and struts for the LGT and put them on the car using the stock Outback 3.0R springs?

 

You can, at least with LGT Konis. The ride height ends up at 16" hub to fender, just about an even gap all the way around outback tires. Rides way better, stays controlled over bumps/uneven roads at high speed, but the springs are still kind of soft for any real performance driving. It's a great daily setup, retains functional amount of clearance but "fixes" the handling issues.

^ I wonder how the koni set up would feel with a 1 inch lift kit to retain OEM ground clearance.

I just ordered the 5058J kit from japanparts and was wondering how long did the kit actually take to come in? Also would you recommend leaving the rear struts at the middle adjustment or would you move them up/down?

I ordered a set of 5058 on Oct 4th and got it on Oct 17th. I was very surprised how quick I got them since it said 45-60 days. Hope it's just as quick for you. Haven't had a chance to install them yet.

That adjustment should mostly help adjust the preload (i.e. stance). I did not change mine. But I am not going to use the springs that came with them either. Plus I also revalved mine. Have yet to install and provide feedback...

 

http://legacygt.com/forums/showthread.php/bonbons-bilstein-bts-kit-260197.html

That adjustment should mostly help adjust the preload (i.e. stance). I did not change mine. But I am not going to use the springs that came with them either. Plus I also revalved mine. Have yet to install and provide feedback...

 

http://legacygt.com/forums/showthread.php/bonbons-bilstein-bts-kit-260197.html

 

Thanks for the feedback!

 

Have you gotten back to M. Schneider about your contact over at bilstein? Sounds like he is looking to do something similar, possibly with some coil-over springs. Id love to see what people come up with as alternate solutions to make these ride better.

No I have not . I will though.

No I have not . I will though.

 

Why not just post the info here?

Why not just post the info here?

 

Cause I've been lazy to ask the guy over there if he is OK that I put his email on the forum. But yeah, I should contact him.

So my attachments are not working today for some reason but this came in!

 

https://photos.app.goo.gl/0GxT0uRVQfdg2Ef42

 

Going to install this Sunday morning. Hopefully it all goes well.

I think you're going to enjoy the ride. But for me, the rear still feels too soft.