What air pressure in Fox airshocks

[John Orchard]

I'm experimenting with some air springing on suspension, can anyone tell what the average pressure they've used in there Fox airshox, about 35 psi?  Do the Fox airshox have dual air chambers?

[09.0]

You put air in the top and the bottom as there are two valves. One is for compression and the other rebound.
You generally put more in the top.
Its more like 150psi, at least 100 any way. You will need a high pressure pump as a compressor won't go high enough. I also use a special gauge so you don't lose most of it when taking the pump off.
 You need to buy the book.

[JohnnyO]

You should use nitrogen in Fox Airshox, around 80lbs in the top chamber and 150 in the lower but it will vary from bike to bike depending on the suspension leverage ratio.
Both chambers are compression, the top is for the first few inches of travel and the lower for the last half of the travel.

[Brian Watson]

You don't have to use nitrogen...even Fox state in their manual that either nitrogen or oxygen can be used...as a guide , I ran in my 1978 Husky 135 in the high pressure (lower valave) and 85 in the low presuure (upper valve)...but there is a formula to work out the numbers .... you can find a copy (free) at the Thor Lawson site... I have a bicycle ( mountain bike) suspension pump which you can get at bike shops that will pump to about 400 psi... I have found this works well..

[motomaniac]

the early models and fox mono's have only one chamber. Pressure depends on length of shock ,bike weight ,rider weight and skill level and as Johnny O said leverage ratio .Get a manual!

[bazza]

Think i have manual if you give info,will look for it

[Moto]

Whatever you use, DONT use oxygen. Oxygen and oil explode.I think you meant air Watto.

[motomaniac]

Whatever you use, DONT use oxygen. Oxygen and oil explode.I think you meant air Watto.

yes air is 80% nitrogen anyway but pure nitrogen will always work better.

[JohnnyO]

Whatever you use, DONT use oxygen. Oxygen and oil explode.I think you meant air Watto.

yes air is 80% nitrogen anyway but pure nitrogen will always work better.

Exactly!

[Viper666]

Tried to put air into Steve Sweeny's YZ400D Fox shock & it actually went down @135lbs.
Had to put it on a stand to take the weight off it to pump it up and it still sags to about half
You need one of those high pressure pushbike pumps.


On another matter the shock will be for sale soon as I am restoring his bike back to original.

0427334186

[crs-and-rms]

what bike model is it  ? .you  need to work out what the suspension lever ratio is first which is rear wheel travel devided by shock shaft travel ,allways set high pressure 1st  it  is the lower valve allways have bike on stand when adjusting presure

[eric318]

Ah, the 100% Nitrogen vs 80% Nitrogen conversation is back
Are they Fox Airshox or Fox Nitroshox?
Is there really oil in the bladders? Snake oil?
Air (O2 + N2) does not behave differently from Nitrogen (N2) under pressure when it comes to the first principle of thermodynamics....
But yes, Nitrogen is much more cool

[JohnnyO]

Ah, the 100% Nitrogen vs 80% Nitrogen conversation is back
Are they Fox Airshox or Fox Nitroshox?
Is there really oil in the bladders? Snake oil?
Air (O2 + N2) does not behave differently from Nitrogen (N2) under pressure when it comes to the first principle of thermodynamics....
But yes, Nitrogen is much more cool

None of the gas shock manufacturers pressurise their shocks with air.. is that just because nitrogen is more cool eric?

[motomaniac]

Ah, the 100% Nitrogen vs 80% Nitrogen conversation is back
Are they Fox Airshox or Fox Nitroshox?
Is there really oil in the bladders? Snake oil?
Air (O2 + N2) does not behave differently from Nitrogen (N2) under pressure when it comes to the first principle of thermodynamics....
But yes, Nitrogen is much more cool

haha ever rode a shock that wasnt bleed properly?
for fox shock the lower chamber is fully mixed with the oil , its called emulsion, only the upper pressure is in a bladder. Fox mono's are full emulsion .ie no bladder .Answer your question?

[eric318]

Actually, I believe so, mostly. More a marketing trick than a real improvement, in my view, at least from what I can see when I do the maths (PV=nRT yadhayadha) with what is left of my physics knowledge. In truth, when I do the maths, there is a difference, but so small that it is unlikely to actually make a significant difference. But hey, I am far from being an expert in anything....

Some put a wing on the trunk of their car and they swear it makes them go faster No offense meant.

I have a pair of Fox Airshox to rebuild, cant wait to get to that part.

As for oil and oxygen being an explosive mixture, hmm, there is some truth in that but it seems to me not really applicable to our use cases.
I seem to remember that this is derived from the physics of the diesel engine (but will not ignite without a source of intense heat...) or the absolute necessity to never apply grease to the threads of compressed oxygen cylinders (memory from veterinary school many years ago). Thankfully the pressure in our shocks or forks can never reach the levels of compressed cylinders, by a long shot...

But hey, again... I am far from being an expert in anything....