This is why you need to change your suspension fluids

[Slide Panda]

- So back when I got my first real bike, at 620 listed on TOB I didn't think or know much about suspension. It looked good, had some go fast bits and I was happy. Like most folks, no real thought to the suspension

I sold it and bought a 900S from another member here (Yes 'Mash, I still have her) that had an Ohlins shock and Race Tech had at the front.
Wow... it felt wwway better.

I knew the suspension was better on paper - but you just don't get it until you're on a bike with superior suspension to what you've had, that's also set up. Since that little epiphany I haven't been so concerned with engine go fast bits and paid a lot more attention to that suspension.

Fast forward a bit to this year. Got a SuperMotoed out KTM 690 that I was taking to the track. Track season closed and it was time for work. Fork refresh was on the list

- This is what was in my forks from 4000 miles of use.

That bucket was brand new. *ALL* that crap came from 3 forks (had a nicked seal on the monster ) And the oil needs to be held to the light to see though.

All that shit blocks passages and degrades the function of the forks. Also, just like motor oil, suspension oil does break down. So after time it's about worthless.

So, as the off months set in for much of the Northern Hemi folks - I encourage you to skip that DynoBazzazNitrus doo-hicky in the hopes that it'll make you 'faster' and spend that money on some sweet suspension love as it will make you faster.

[MonsterHPD]

Yes, you really wonder where all the shit comes from.

Don't forget, the amount of oil in the shock is even smaller than in the forks (at least I think so...), and the shock works even harder than the forks do.

If you have an Öhlins or similiar, send it in for service every 2 to 3 years or so, if you have an OE budget non-serviceable unit, I suppose hope for the best is all you can do short of upgrading!     

[Slide Panda]

Shocks are a smaller volume but better sealed up and pressurized. Not to say they don't need TLC. But I was at a recent suspension talk from a Penske rep and he said street use shocks could go longer 2-3 year between services vs the forks which should bee seen to on a roughly annual basis.

Some is crud that got past seals, some is tiny bits of the shims wearing away from their action... some who knows.

[ducpainter]

You should see what happens to the shims when you've really let it go too far.

They actually pit and no longer seal.

@MonsterHPD...you're absolutely correct about the shock seeing more severe service...and Ducati doesn't even recommend service at any interval even for the units that can be serviced.

[Howie]

At 18K the oil in my Ohlins, though debris free, was quite burnt.  New oil made quite a difference.

[Slide Panda]

Yep - that seems to be the usual thing for the shocks. Not so prone to crud as the forks so they can last a bit longer. But the oil will burn out at some point. Of course your milage will vary blah blah...

As with all things - harder you ride it the sooner it'll need TLC

[brad black]

that oil's fine.  wait till you get some come out that's grey with bits of sludge and that smell with a nastiness akin to bong water.

[Slide Panda]

Saw some stuff on a bike that had a leaking seal for a while and of unknown age that resembled gogurt kids yogurt.

[Armor]

Sealed shocks on cars last 100,000+ miles.  I wouldn't worry about the rear shock.

[Slide Panda]

Well considering my shock developed a leak that resulted in a gas pressure drop around 30 and felt oh so much better after a refresh ill disagree.

Also having seen some forks that people said "felt fine" that had sludge, smelled bag enough to clear the room or had almost no oil ill be attending to my forks regularly

Much about a bike doesn't last as long without service as a cars. Suspension items don't diverge from that

[ducpainter]

Sealed shocks on cars last 100,000+ miles.  I wouldn't worry about the rear shock.

Define 'last'. 

Another thing to consider is you tend to get used to things.

Performance degrades over time and you don't realize there is anything wrong until someone that knows (your tech) what it should feel like suggests some work.

You have it done and you realize how bad it was.

[MonsterHPD]

It's 2013 here now, so happy new year everybody 
I had my first shock service made after I ran out of adjustment on my Öhlins shock,  maybe after 3 years or so of service, don't remember exactly anymore.
Anyway, after a service I was back to my original settings, so there is certainly a degradation over time (or usage ...), that is cured by a service.

My Golf '97 still has original suspension all around, it's not bad enough to offend, but I'm not sure it's really "good"... I've spent 15 years getting used to it 

[Speeddog]

that oil's fine.  wait till you get some come out that's grey with bits of sludge and that smell with a nastiness akin to bong water.

I refreshed a set of 900SS forks that hadn't ever been apart.

That's a pretty good description of the smell of the oil. 

[He Man]

On this topic, does anyone know if all seals need to be replaced on a serviceable shock? (999 showa) or can i get away with not repalcing them? I have no problem replacing them, if i knew where to get a seal kit!

[ducpainter]

I look at seals like cheap insurance.

Why bother refreshing the shock and not replacing seals?