How do I charge my coilovers with nitrogen?

mjp1080 · May 5, 2009

I need some guidance on how to go about charging my coilovers with nitrogen, they come empty from the manufacturer. I have never had to do this so I need to know. What tools and or steps are required and, is there a shop that could perform said service if needed?

TheMasterbater · May 5, 2009

its easy, you just gotta know people with proper tools. I happen to have the proper tools. And am Pro at it now since we recharge the race car shocks everyweek.

If you have a nitro bottle i've got the gauge.

crash2 · May 5, 2009

I had the last set I used done at the bike shop next to work (speedway) in monroe.

They can only be charged with the shock extended.

Bunk1 · May 6, 2009

crash said:
They can only be charged with the shock extended.

Has anyone broken this rule?

super samurai · May 6, 2009

i tryed it a few times before i figured it out

Binder · May 6, 2009

Bunk said:
Has anyone broken this rule?

How could you? I don't think a high pressure hose would hold enough pressure to get the gas from the tank to the shock.
Why don't you try it and let us know..

Bunk1 · May 6, 2009

Binder said:
How could you? I don't think a high pressure hose would hold enough pressure to get the gas from the tank to the shock.
Why don't you try it and let us know..

Ive seen it done.

Binder · May 6, 2009

Bunk said:
Ive seen it done.

Lets hear some details.....How did it work?

crash2 · May 6, 2009

Bunk said:
Has anyone broken this rule?

I don't know, just how I have heard you wanna do it unloaded/extended. Now it may vary between a res and emolsion type shock. With a res style due to how the bladder is built when you are sitting with weight on the shock, once you pressurize the bladder you are working against weight. Now emolsion I would think it would not matter since the nitrogen will go into the shock and equilize on both sides of the valve within the shock. At least thats how I see it...

Boonie Buster · May 6, 2009

I used a bicycle pump. :awesomework:

darius · May 6, 2009

Boonie Buster said:
I used a bicycle pump. :awesomework:

uhh air aint the way to go buddy

Bunk1 · May 6, 2009

crash said:
I don't know, just how I have heard you wanna do it unloaded/extended. Now it may vary between a res and emolsion type shock. With a res style due to how the bladder is built when you are sitting with weight on the shock, once you pressurize the bladder you are working against weight. Now emolsion I would think it would not matter since the nitrogen will go into the shock and equilize on both sides of the valve within the shock. At least thats how I see it...

Agreed, I was just wondering out loud.

I dont know how the rig worked afterwards but nothing blew up or failed on the shocks.

I dont know any better so i will do what i hear is the norm, Until prooved otherwise.

Brian H · May 6, 2009

Bunk said:
Agreed, I was just wondering out loud.

I dont know how the rig worked afterwards but nothing blew up or failed on the shocks.

I dont know any better so i will do what i hear is the norm, Until prooved otherwise.

Clay did my nitro shocks underload at koh. We lifted it by hand a bit and it seemed to have held it at ride hieght.

Nuzzy · May 6, 2009

Here's a brief description I just saw the other day on the subject of charging at ride height. May or may not be interesting and/or valid...

Tab said:
Why the hilift? Pat said he called sway-a-way and they said to just charge them on the vehicle and theres no reason the extend them.

whiterhino said:
Because in most cases your regulator won't go high enough to charge them in the ride ht position. My regulator goes up to 600 psi. I tried to charge them and my rig dropped, not rose. It's a ratio of volume & pressure.

Say you charge them at 160 psi fully extended. (that's roughly what you will need, somewhere between 160 and 200) If you want to put in that same charge at 6" ride ht (12/6 the stroke), you will need to increase the pressure by a factor of 2, or 320 to 400 psi. If you want to charge them at 3" ride ht (12/3 of the stroke), you will need to increase the pressure by a factor of 4 or 640 to 800 psi.

So, unless your regulator goes up to something close to 1000 psi, you can't do it.

Bunk1 · May 6, 2009

I figured there had to be some formula to get it right. I wonder how precise it is. Then again if ya never charged fully extended i would think you can have a feel for it with a bit of experimentation.

Corey Y · May 6, 2009

Nuzzy said:
Here's a brief description I just saw the other day on the subject of charging at ride height. May or may not be interesting and/or valid...

I don't think that is right. While at KOH '09 Steve from Evergreen had the shock tuning specialist from Bilstein check his coilover pressure and he said that they should be charged at full extension but they can be done at ride level but the pressue will vary, but not as much as White Ryno said. He said it depends on how much shaft is showing and where the internal piston is. I think the Bilstein guy put @160lbs in Steves coilovers at ride level.

JPFREAK · May 7, 2009

Crazy Daze said:
I don't think that is right. While at KOH '09 Steve from Evergreen had the shock tuning specialist from Bilstein check his coilover pressure and he said that they should be charged at full extension but they can be done at ride level but the pressue will vary, but not as much as White Ryno said. He said it depends on how much shaft is showing and where the internal piston is. I think the Bilstein guy put @160lbs in Steves coilovers at ride level.

I think this is closer to correct. I have checked my pressure at ride height and found it to be around 180PSI, the shocks (coilovers) were charged to 150PSI fully extended. This is going to be different for every rig.

mjp1080 · May 7, 2009

All good info, thanks guys! I talked to the bike shop in monroe they said they would do it.:awesomework:

benw1 · May 7, 2009

The pressue variation between full extension and ride height depends on the diameter of the shock shaft. An air shock will have a huge variation (big shaft) and a coilover will have a smaller variation (small shaft).