Shock Oil and PSI

[He Man]

I found 35 PSI (yikes!!!) in the nitrogen bladder today.


What PSI should i get the shop to refill it with? Im 150lbs

I planned on filling her up with 2.5wt. THe original stuff in there was pretty light.

[FrankenDuc]

your favorite answer - it totally depends  
think in the EDIT 100-300psi range,
double checked for a more universal answer, Racetech suggests "about 50psi" (think i was confusing socks with oleo struts or something...) /EDIT
whatever it takes to prevent the oil from cavitating, with your specific valving of course..  Higher is better for cavitation, but higher more throws off your spring rate...
Do you know what the shock and its shimstacks were originally built to?

[He Man]

50psi? is that right? this is a non emulsion type so theres a bladder involved. I always heard 150psi is the norm.

[Speeddog]

Which shock are you talking about?

Showa?
Ohlins?
Penske?

[He Man]

999 Showa

[FrankenDuc]

50psi seems very low to me too, so I don't think I'd trust my parroting of RT... 

[He Man]

yea 50 seems really low. Im having a hard time pulling the damn shaft off. Everything on this shock is jammed up the wazoo. Me thinks its time to just get another shock.

[FrankenDuc]

The nut holding the piston on the shaft? 
I haven't been inside the Showa shock, but the threads on the shaft are most likely peened, which would need to be ground off - looks like you just want to ground around the outer circumference of the shaft, as there may be some rebound valve parts peened to the inside of the shaft.

Or, Penske! 

[He Man]

no the cap that covers the main piston. ive been banging on it and it looks like all sorts of make the beast with two backsed up and it aint coming off so i can pull the shaft out.

i am too poor to buy a $1,000 penske. I might pick up a used one for $600 thats about the max of my budget. and im not willing to send this out cause i might as well jsut get teh penske at that point!

[FrankenDuc]

ahh, that part... propane torch and a 20lb sledge hammer?

Managed to pick up a used Penske shock a little while back for <500, double clicker not a triple but lucked out with a digressive setup - it was the absolute worst thing I could have possibly done for the performance of my bike's forks...

[He Man]

Well i took that part off, topped her off and sealed her up.

BUT. Ive called 15 shops in NYC. no one does nitrogen. ;\


THe one i thought WOULD do it (duc soho) is not allowed to have nitrogen in the shop....

wait... its not flammable, we breathe more of it than air in everyday...and its...nope nvm. let me just stop asking questions. :\


i wish you guys hear some of these responses im getting

"you dont need to recahrge it with nitrogen"
"no ones ever requested that"
"just use air"

i mean really! after shipping charges and rechrage cost i might as well as buy the reharge station and use the nitrogen at school!

[Slide Panda]

THe one i thought WOULD do it (duc soho) is not allowed to have nitrogen in the shop....

What the hell?

Though not any direct help to this application - I learned from a Penske rep that race teams will run as low a pressure as they can without allowing for cavitation. Lower pressure allows for better performance in the shock. Of course these are shocks that are seeing a race or two between being attended to/inspected, not ones that will see a year or two (or more) between TLC sessions

[Howie]

Well i took that part off, topped her off and sealed her up.

BUT. Ive called 15 shops in NYC. no one does nitrogen. ;\


THe one i thought WOULD do it (duc soho) is not allowed to have nitrogen in the shop....

wait... its not flammable, we breathe more of it than air in everyday...and its...nope nvm. let me just stop asking questions. :\


i wish you guys hear some of these responses im getting

"you dont need to recahrge it with nitrogen"
"no ones ever requested that"
"just use air"

i mean really! after shipping charges and rechrage cost i might as well as buy the reharge station and use the nitrogen at school!

You could run it up to ECS.

[He Man]

after tolls and gas, they are way too far out there. There are some shops on LI...but...i used air. I have a dehumidifier inline with my compressor. It hardly had any water in there today since its a cool dry day and Air is 78% N2 anyway. I can't see what could possibly go wrong.

soo...ill check back with you guys if it blows up ( im pretty sure it wont, that thing can hold up to 200psi, and ive only got 150 in there. any boiling moisture isnt going to increase 50psi, even if that bladder is small.

Seeing how easy it was to get into the shock after all the hammering and scars i made...im thinking about doing the racetech gold line valve next time around. But damn those penske shocks are WAY easier to get into.



This is new fluid, the old stuff was quite dirty. I used 2.5wt

[FrankenDuc]

Rad!
Glad to hear it's not impossible to get into the Showa. I've got one on another bike I've got to dig into and revalve (again, thanks to the Penske experience turning it from a top performed to an utter pile of...), so I really appreciate knowing from this thread the trouble I'm going to face.

If nothing else, the plain air will get you by.  Check tire and speed shops in your area too for nitrogen, I hear it's the latest fad to run it - "they" say since the molecules are bigger it leaks a whole lot less. And for the speed freaks it makes setting tire pressure a bit more trivial... Cold, hot, what? Is there a difference?..

And, in the meantime, ride hard and fast - the extra airflow will keep your shock cooler and reduce the effect of the air expanding