sean-emmett

hi guys

im in the uk and got myself a showa race shock off ebay that was listed as a race shock off some guys firestorm race bike.

anyway i have measured it all up next to a standard firestorm shock and all is the same. only i cant find no info on it. it has a remote compression cylinder that needs to be pumped up yet i dont know what psi to pump it to.

any info whould be great.

thanks
mark

Hawkrider

It should already be pressurized. It is pressurized with nitrogen only, and should be done by a good suspension service center. Normal is about 150-175 psi.

sean-emmett

hi,

the remote cylinder has a valve on it that is the same size for a foot pump or bike pump.

does it not get pumped up with just air? so i would have to have it sent off to a service centre?

thanks
mark

Hawkrider

No, it is NOT air. It's Nitrogen, and a special fitting has to be used to pressurize it. One little puff of gas is like 25 psi because the resorvoir is so small, so your regular air pump or even air chuck won't work. Nitrogen is used because its volume changes less with temperature, therefor pressure will change less with temperature, for the same volume. It is also less reactive than air (oxygen, humidity, etc).

JamieDaugherty

You can put air in there but only as a temporary test. I do this to check for leaks, I'll put 100psi of air in the reservoir overnight and check for leakage the next day. If everything is ok I release the air and put Nitrogen in. Contrary to a previous post, the typical is either 175 psi or 250psi.

Do you have any pictures of the shock? It sounds like a pretty rare item.

Hawkrider

I guess it depends on the shock brand, as Elka runs about 150# and Fox 175#. I'll be honest, I'm not sure about Showa or Ohlins. It really depends how close the shock is valved to being on the verge of cavitation. The closer it is, the higher the pressure needs to be to prevent cavitation.

JamieDaugherty

FYI - Fox recommends 250psi in all of their shocks. I don't know about "back in the day" but in the past 10 years that I've dealt with them it's always been the same. The pressure that the Elka's have seems low, I wonder why it's that way. Less seal drag maybe.

Hawkrider

We measured 150 in the Fox when recieved. Dyno'd with no obvious signs of cavitation. We put 175 back in and had a smoother graph, though no cavitation once again.