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Discussion Starter · #1 ·
Post up any discoloured or corroded shims you find and what oil they were using. Let's try to find some trends.

Shims from a Rockshox Charger. Oil used was Redline ExtraLight 2.5wt (blue) which had been in long enough to degrade to a darker colour.

Circle Turquoise Aqua Teal Silver
 

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Lack of maintenance doesn't discolour steel shims.
I've been running Redline 2.5wt and 5wt fluids in a topaz. Shims are still nice and shiny after 3 years. Fluid has been changed at damper bleed time.
I wonder if the charger damper wasn't fully flushed / cleaned between different fluid brands being used? Maybe it was a reaction between different fluids that caused a shim issue?
 

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This is the geekiest thread ever. I wish I had pics of some of the ones I've seen.

I'll keep an eye out. I have a DHX2 I'm digging in to next week so I'll check her out...

mk
 

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99% of the discoloured shims I see are Fox shocks in the factory 10wt oil, usually on the compression side

Security Circle Steel Cable Silver

This is an unusual one again a fox shock, but the pattern did line up perfectly before I undid the shim stack, except it skipped a shim!
Household hardware Metal Circle Aluminium Silver
 

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Discussion Starter · #12 ·
Is it possible air was trapped in the damper?
All oil contains air. You can get most of it out by vacuum degassing, but it does get back in.

99% of the discoloured shims I see are Fox shocks in the factory 10wt oil, usually on the compression side

View attachment 1253514
This is an unusual one again a fox shock, but the pattern did line up perfectly before I undid the shim stack, except it skipped a shim!
View attachment 1253515
Fox 10wt red (aka Silkolene) they recommended for aftermarket but never used in production or The Torco they actually shipped with?

I've found Torco RSF Medium (32 cSt) in yellow, orange and red.

This one was definitely due to lack of maintenance, and signalled the end of the shock, a Specialized/Fox brain shock ~2012

View attachment 1253517
That nasty yellowish stuff?
 

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Fox 10wt red (aka Silkolene) they recommended for aftermarket but never used in production or The Torco they actually shipped with?

I've found Torco RSF Medium (32 cSt) in yellow, orange and red.

That nasty yellowish stuff?
Factory Torco, I don't know many people who actually use the Fox red!

Yellowish stuff appeared to be about 80% water 15% rust and maybe 5% of some kind of suspension oil, I presume whatever Brain shocks get at the factory
 

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Discussion Starter · #15 ·
Factory Torco, I don't know many people who actually use the Fox red!

Yellowish stuff appeared to be about 80% water 15% rust and maybe 5% of some kind of suspension oil, I presume whatever Brain shocks get at the factory
Plus 5% black gunge from degraded rubber seals. I need to ask some Specialized people what that oil is!

BMS 3-11, haha.
I looked up some Skydrol a few years back to see if I could get some for testing. Quickly gave up after reading the MSDS!

One well known suspension company is however using 5606 fluids as their high grade shock oil.
 

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I looked up some Skydrol a few years back to see if I could get some for testing. Quickly gave up after reading the MSDS!
Yea, there is a reason why we call it the 'purple people eater'. It's pretty nasty stuff and doesn't have great lubrication characteristics. Petroleum oil FTW when it comes to suspension fluid.

One well known suspension company is however using 5606 fluids as their high grade shock oil.
That doesn't surprise me. Red oil (aka 5606) is what's used in landing gear oleos, which of course is a spring and damper. As opposed to Skydrol, red oil is much nicer to work with. Have you experimented with using it, Dougal?
 

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I've serviced dozens of dirt bike and street bike forks for myself and friends as well as shocks. Shims have always looked like that after a year or two for anything I've ever opened up. I've used quite a few different oils over the years as well. I have 4 different kinds on my shelf right now from Maxima to Honda to Bel Ray to Torco.
 

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Discussion Starter · #18 ·
I've serviced dozens of dirt bike and street bike forks for myself and friends as well as shocks. Shims have always looked like that after a year or two for anything I've ever opened up. I've used quite a few different oils over the years as well. I have 4 different kinds on my shelf right now from Maxima to Honda to Bel Ray to Torco.
With Moto suspension is it possible to nail down what the original factory oil was?
At least in the bike industry it's relatively transparent with what they use.

I had another Charger 1 damper on the bench yesterday of the same age as the first (2016). Shims are shiny and bright on all sides. It had the original Maxima/RS 3wt inside.
 

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For moto you really only have 3 brands which would be KYB, Showa or WP. KYB and Showa use their own brand fork oils - Kayaba 01 and Showa SS7 most of the time in their forks. For WP they have their own branded 5wt fork oil now but that hasn't been around for that long and I'm not sure what they used before that.
 

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For moto you really only have 3 brands which would be KYB, Showa or WP. KYB and Showa use their own brand fork oils - Kayaba 01 and Showa SS7 most of the time in their forks. For WP they have their own branded 5wt fork oil now but that hasn't been around for that long and I'm not sure what they used before that.
Doubting it's truly their own brand oils, it's just rebranded something else. Not even car manufacturers are going to make their own oil refineries it's all rebranded something else (Castro etc).
 
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