Fox 2.0 coilover air shocks

[TBItoy]

So you are saying that compressing a "gas" in a fixed volume cylinder does not increase rate?


Remember, although the piston is letting fluid past as the shock compresses, the shaft (and it is big on these shocks) is ALSO displacing fluid which compresses the "gas". As the gas compresses, the "rate" rises.

Bump stops have the same setup, at least mine do, minus the spring. As the airbump compresses rate increases.

I know for a fact if my ride is too soft, adding N2 will stiffen it up.

Technically y'all are both "right".

If you think about the loading on an air shock, you are using the oil volume to not only flow through the piston to damp the movement, but it is also changing the internal volume of the shock. More oil = less room for N2 to compress.

That's why it's a good idea to only charge air shocks at full extension. The pressure in the shock with the weight of the vehicle on it is a LOT more than when you initially charge it.



On an air bump, it sits static at full extension, so charging to a higher static pressure gives you a higher initial "spring" rate. The air bump is not acting on the suspension at ride height, therefore it can't affect ride height.

On an air shock, charging to a higher initial static pressure will simply raise ride height.

(Think of it as changing to a stiffer rate coil spring, same static length as the old spring, but leaving your coil mounts in the same location... The rig's weight didnt' change, so the rig will sit higher, because it can't compress the spring as much)



The actual pressure that you put in an airshock is not important, except as a reference to know if you need more or less to get your ride height where you want it.


The rule of thumb when tuning air shocks is:
Charge shock to whatever pressure needed to get ride height you want > drive rig
Does it bottom out easy? > Bleed off charge, Add Oil
Does it ride too stiff?> Bleed off charge,Subtract Oil
Repeat first step.

 

[pachary]

Yes, the nitrogen charge in a "hybrid coil over" effects the ride height. But because they also have coils, the coils are intended to support the vehicle.


I still maintain the N2 pressure does effect overall spring weight and is progressive(at a fairly rapid rate).




Use this example to understand the spring action in these shocks.

Take the piston head off of the shaft (assume the shaft will stay centered)

Put "x" amount of oil in shock.

Charge extended shock to 20 psi.

Compress shock.

As the shaft, which on my shock is 1.25" in a 2" shock body, goes into the body it displaces oil.

The only place for the oil to go is into the space occupied by the N2.

As the oil compresses the N2, the pressure increase (again at an exponential rate).



Nitrogen in a "hybrid coil over" has a significant effect on compression and rebound. It acts as an additional spring in the system.

I have this type of shock on my buggy and have tweaked on them extensively.






You can actually use these as a typical emulsion coil over with a minimal nitrogen charge to help with oil aeration.

 

[TacomaJD]

Re:

Taking my spare tire (39 Krawler on steel 17" rim) out of the bed helped my body roll a little. Also made it ride almost 2" higher in the rear on flat ground too.


.....just adding that info, not that it's relative to anything. Plus I'm currently a little drunk and it seemed fitting. Lol Mash Yer Motor