Mag ride strut

[Leevr]

I've got a question about my mag ride struts. I'm aware of the magnetised iron filings and how they increase resistance, but on my strut faces I have a sticker that says Warning do not heat or open gas pressure. As far as I'm aware oil is a medium not a gas. So my question is. Does the strut use both oil and gas? Yes I've googled it and I'm still in the dark. I'm sure someone within 2 minutes of looking will give me an answer that was staring me in the face. Cheers in advance.

 

[Leevr]

 

[AJB]

Most shocks have both oil and gas. The oil (with magnetically affected particles in the case of adaptive dampers) is what actually provides the damping as it gets forced through small holes. Gas would flow through the holes too easily, without absorbing movement/energy.

But oil at atmospheric pressure can form bubbles when it's under vacuum. So if you pull the piston out, the area beneath starts to form a vacuum. I'm not 100% sure on the physics here, and whether it's just bubbles of "vacuum" (ie nothing) or whether it's dissolved air and/or components from the oil, but either way it's not ideal. By having a separate gas reservoir under pressure, all of the oil is always at a positive pressure, and so those effects are removed or greatly reduced. So the same pressure difference above/below as the piston moves might now be "slightly above atmospheric vs lots above atmospheric pressure", rather than "almost vacuum vs above atmospheric pressure".

So yes. Long answer short, both. Oil as the damping medium, and gas to keep that oil under pressure.