CSG and RCE tag-team suspension Q&A thread! Ask us anything! - Page 328 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

BishamontenZC6 · 01-17-2026, 07:37 PM

Question about the infamous conical washer on KW based coils. Why exactly and technically some people recommend it and what problems could occur if it’s not installed between spring perch and Group N top hats ?

Also, why KW and ST installation manuals don’t mention it, only RCE does ?

fminicooper · 01-19-2026, 01:51 AM

Hi,
I’ve had a failure on the shock absorber rod.

Setup: FRs 2016, NA engine, Bilstein B6 dampers, Pedders top hats, Eibach springs, –3° camber. About 30,000 miles total, including several aggressive track days.

Has anyone experienced a similar issue?

Scargod · 01-19-2026, 02:52 PM

Breaking at that spot is common, if it's going to break. Were you banging curbs?
I don't know Pedders top hats, or the Bilstein's, but if that's a 12mm shaft then that may be your answer. Most front, high-end racing dampers are a minimum of 14mm diameter.

Racecomp Engineering · 01-19-2026, 05:39 PM

Quote:

Originally Posted by Scargod

Breaking at that spot is common, if it's going to break. Were you banging curbs?
I don't know Pedders top hats, or the Bilstein's, but if that's a 12mm shaft then that may be your answer. Most front, high-end racing dampers are a minimum of 14mm diameter.

That's not the damper shaft since it's an inverted strut. The damper shaft is inside the body and at the bottom.

The breakage could be from a variety of things, most commonly in my experience from from a bit too much torque on the top nut. It happens. I'd just have Bilstein rebuild the dampers.

- Andrew

Scargod · 01-19-2026, 07:14 PM

You got me there. I wasn't paying attention. Still, couldn't it be small for hard racing?
You rightly corrected me, yet I've had no response for the question I asked...

Racecomp Engineering · 01-26-2026, 10:41 AM

Quote:

Originally Posted by Scargod

You got me there. I wasn't paying attention. Still, couldn't it be small for hard racing?
You rightly corrected me, yet I've had no response for the question I asked...

It's just hard to tell the cause in this case. There are tons of 12mm top nut struts out there doing just fine. An improperly torqued top nut could certainly push it over the edge. Or a materials defect, or a massive impact that also would wreck a 14mm top nut, etc...

- Andrew

01-19-2026, 01:51 AM	#4580
fminicooper Senior Member Join Date: Dec 2017 Drives: FRS Hot Lava Location: Houston Posts: 131 Thanks: 103 Thanked 70 Times in 44 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Bilstein B6 failure Hi, I’ve had a failure on the shock absorber rod. Setup: FRs 2016, NA engine, Bilstein B6 dampers, Pedders top hats, Eibach springs, –3° camber. About 30,000 miles total, including several aggressive track days. Has anyone experienced a similar issue? Attached Images

01-19-2026, 02:52 PM	#4581
Scargod Track Day Junkie Join Date: Nov 2021 Drives: 2022 BRZ Limited Location: Connecticut Posts: 183 Thanks: 105 Thanked 141 Times in 79 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	Breaking at that spot is common, if it's going to break. Were you banging curbs? I don't know Pedders top hats, or the Bilstein's, but if that's a 12mm shaft then that may be your answer. Most front, high-end racing dampers are a minimum of 14mm diameter. __________________ Try this Jalapeno son! It ain't hot... BLUE 2022 BRZ, Scargod's Mod's and Track Upgrades Scargo on IWSTI (Journal of STI track car-for sale) Track Day Videos on YouTube

01-19-2026, 07:14 PM	#4583
Scargod Track Day Junkie Join Date: Nov 2021 Drives: 2022 BRZ Limited Location: Connecticut Posts: 183 Thanks: 105 Thanked 141 Times in 79 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	You got me there. I wasn't paying attention. Still, couldn't it be small for hard racing? You rightly corrected me, yet I've had no response for the question I asked... __________________ Try this Jalapeno son! It ain't hot... BLUE 2022 BRZ, Scargod's Mod's and Track Upgrades Scargo on IWSTI (Journal of STI track car-for sale) Track Day Videos on YouTube

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01-17-2026, 07:37 PM	#4579
BishamontenZC6 Member Join Date: Apr 2022 Drives: '14 BRZ Limited Location: Switzerland Posts: 38 Thanks: 6 Thanked 24 Times in 10 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Question about the infamous conical washer on KW based coils. Why exactly and technically some people recommend it and what problems could occur if it’s not installed between spring perch and Group N top hats ? Also, why KW and ST installation manuals don’t mention it, only RCE does ?

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