Any ideas on a cheap Nitrogen charging setup

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#1
I am in the process of restoring several vintage and evolution bikes and all of the shocks will need rebuilding. Any suggestions on purchasing a N2 bottle, regulator and gauge? It isn't cost effective to have a service dept. charge these in the San Antonio area.:scream:

Suggestions are welcomed!
 

SATxMotoX

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#2
How high of PSI do you need to pump things back up? If it's under 200 PSI then I'd say the cheapest solution is to go to a (pedal) bike shop (like Broadway Bicycle shop or one of the others here in SA) and buy a high pressure air pump. They make air pumps for some of the Mtn. bikes that have air shocks and they will pump up to about 200 PSI. I believe they'll cost around $50 or so.

Another alternative is to get a scuba tank, regulator, and shutoff valve. I used to play paintball and we used a scuba tank setup to refill out air bottles on our guns. The tank would hold air at about 3000 PSI so it would be a little overkill for you but it's an alternative. I'd check with the paintball stores in-town, they'll be able to hook you up with what you'd need. The only thing differnet you'd need is a zerk (is that what it's called?) fitting to attach to the air fitting on the shocks.

BTW - where do you like to ride here in SA?

Good luck.
 
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#3
Thanks, I thought about the bicycle angle, but haven't been able to find a pump with a no-leak Schraeder valve that will let you remove it without loosing pressure. The other problem is that air tends to heat up as you ride and you get an increase in pressure within the shock (nitrogen is more resistant and also is free of oxygen and the rust problems that are inherent to oxygen).

I like to ride at Zars Ranch, VP, and up at RPMX in Bastrop, but this has been a year of chemotherapy (skin cancer) and I haven't been on my bikes since April.:( Looking forward to the winter time when I am done with treatment and have enough energy to load my bikes and go putt-putt. Should be hell on wheels after this layoff!:p
 
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#4
I have a spare Nitrogen tank. You will need a gas welding regulator setup and away you go.
The tank will need an inspection. It is about 2 foot tall and usually cost me 15 US to fill.
Make an offer and pay shipping and it is yours. Actually I have 2 spare tanks. They are good but safety inspection is due.
 
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#5
I go to my local John Deer dealer. They always air them up. They never want anything for doing it. I always give them a five or somthing for thier trouble though.
 
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#6
PowerStroke, I may take you up on your offer as long as the tanks pass the safety inspection(I will pay for it, or will need to know where to do it around me). I guess with a fairly free tank, I can splurge for the regulator, lines, and the special valve it is not too expensive.
 
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#7
It will pass. Stainless and looks brand new.. I gave one to my bud and it passed ok. Remember you need a regulator that will goto 250 so you have some leadway.
 

KawieKX125

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#8
Where do you get the tanks inspected? Do you have a regulator that you will sell? I am a MORON when it comes to anything like this.
Thanks
 
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#9
Air vs. Nitrogen

Husky Texan,
I know several people who use air on a regular basis. After all, air is more than 3/4 nitrogen. The small amount of other gasses (and possibly water vapor) aren't present in large enough quantities to create much of a problem. I also know of someone who did some experimenting on a shock dyno between air and nitrogen and they couldn't detect any difference. Anyhow, I'm surprise that you can't get a service department to just charge the shock for $10-15! Sure beats several hundred for the right equipment, unless of course you are planning on doing tons of shocks :) . If you need a high pressure air pump, try www.mscdirect.com. They have several models that can reach more than 200 psi and one has an air chuch accessory (so you wont loose any pressure when you have filled the shock).
 
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#10
I thought the nitrogen was used to cool the shock? That's what I've heard anyways. Is it true?

Jeremy
 
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#11
HondaXRguy,

No, the Nitrogen is NOT used to cool the shock. Long story short, it keeps the oil under pressure, therefore preventing the oil from cavitating.

Anyone who tries to sell you "cooling fins" for you reservoir or "oversized reservoir caps" designed to increase the N2 and cooling capacity of the shock, probably has a bridge in Brooklyn that they'd like to sell you also.

:silly:
 

JB

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#12
you can go to your local airport and find a aircraft maintanance shop. they use nitrogen in landing gear for the same reason. they will have the equip to charge shocks.
 
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#13
Hondaxrguy,
As WhiPit said, the nitrogen is there to help prevent cavitation and also to make the shaft seal work better. Gasses are rather poor conductors of heat and actually help insulate things. The larger capacity caps help by adding volume which keeps the pressure more consistant as the shock displaces oil into the reservoir.
 
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#14
What about....

a sealed bladder system. Looks like if the gasses dont come in contact with the oil, then air would be fine. It was my understanding that nitrogen, being inert and dry, is better IF it comes in contact with the oil or internal parts.
 
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#15
KX125.,

Any welding supplier or gas supplier. If they have oxygen and acetylene they usually have Nitrogen.

KEEN Air , BOC Gases look in Yellow pages.

I think Nitrogen is used because it is more stable and if you look on the PERIODIC TABLE it has a higher numeric nuimber. This means it is a bigger atom and doesn't permeate the bladder medium as easy per say as Hydrogen or Oxygen. Plus if pure oxygen comes in contact with oil it is a fire hazzard. Imagine putting Hyddrogen in a shock and having it blowup in your face.
nitrogen is inert and plentiful as well as cheap.

Just don't take it to go scuba diving!