[Mrwhlr]

2022, 175 psi. Fox numbers are stupid low.

 

[seitenryu]

Higher IFP pressures prevent cavitation and air ingress into the damper. But they cause more seal friction and more preload. The effect on spring-rate is minor. The one I measured was 10lb/in.

Lower IFP prssure makes them feel all nice and smooth and sensitive in a push test. That is all.

Would you set the IFP pressure to match air sleeve pressure to avoid issues?

 

[LaXCarp]

Does this also remain true for IFP pressure within a DHX2?

 

[seitenryu]

Does this also remain true for IFP pressure within a DHX2?

Wouldn't think so, as there's no pressure on the other side of the shaft seal. I think that's the worry with the FX2, since the max air sleeve pressure is so much higher than the IFP pressure.

 

[LaXCarp]

Wouldn't think so, as there's no pressure on the other side of the shaft seal. I think that's the worry with the FX2, since the max air sleeve pressure is so much higher than the IFP pressure.

Ah ok that makes sense. Thanks for the reply. I rebuilt my dhx2 last night and set it at 200psi. If it doesnt ride well for any reason its easy enough to put back to 150

 

[MTB Engineer]

Not correct. The IFP separates oil and the air / nitrogen charge in the damper so regardless of what spring is used, air or coil, damper function will be the same during compression and rebound.

My experience is that lower IFP pressure will lead to lower lockout force, softer compression damping but also more movement of the IFP, which will eventually cause wear and leaking of the IFP seal.

 

[reo-fahrer]

Not correct. The IFP separates oil and the air / nitrogen charge in the damper so regardless of what spring is used, air or coil, damper function will be the same during compression and rebound.

My experience is that lower IFP pressure will lead to lower lockout force, softer compression damping but also more movement of the IFP, which will eventually cause wear and leaking of the IFP seal.

and since the X2 and Float X2 are twin tube shocks, none of your points apply in this case. Besides that, what @seitenryu said.

 

[MTB Engineer]

Sorry, should have red seitenryu’s post more carefully. I have not played with IFP pressure in a twin-tube shock, but I can see how the shaft seal could potentially leak though wouldn’t this only happen if the IFP pressure was much higher than the air spring pressure, so not really an issue on the X2 but could be on the DHX2?

 

[Dougal]

Everytime the main shaft seal gets a pressure reversal it can pump some air.

 

[LaXCarp]

Wouldn't think so, as there's no pressure on the other side of the shaft seal. I think that's the worry with the FX2, since the max air sleeve pressure is so much higher than the IFP pressure.

I guess I meant more generally, should we be increasing the IFP pressure within the DHX2 as well, not pressure matching. I have the avy upgraded IFP in my shock so that should help in the that dept.