Rear Air Shock: Negative Air Pressure Setup

I’ve just got my first rear air shock. Always had coil. It has two valves. The manual for the shock is missing information. Tried googling, but keep seeing stuff like “equilise the air pressure”

Frame is a Ghost Lanao FS, came with a DNM AOY-36RC.

Manual states main air chamber takes upto 250psi, and that the negative air chamber takes 50-80psi. Obviously I can’t equalise manually when there are two volumes. Putting air in the main chamber is easy and precise the negative air chamber is finicky.

Manual states how to get sag with the main air chamber, but nothing at all about the negative air chamber.

What should I be doing here? Going to take the bike out tomorrow to setup the gears and get used to it. Don’t want to damage the shock or bend the shock spacers.

I’m not familiar with your bike or shock, but I’ve used RockShox DualAir forks for many years. The basic idea on setup is to release all the pressure from the negative chamber and set the positive pressure first. You need to set this so it doesn’t blow through the travel on the biggest hits you normally ride. Once you have the positive pressure set, then use the negative pressure to fine tune it over small stuff such as roots and potholes. Increasing the negative pressure will make it more supple, but sag more. Ultimately, you need to experiment to find what suits you.

Okay. Deflated and filled positive, set sag, then filled the negative (difficult as pumping seemed to give random results). Can’t see what difference the negative chamber made whilst bouncing the bike in my dining room. During daylight tomorrow I’ll give it a test ride.

There is some top out. Nothing I can do takes that away. I ended up setting the sag at 20%. Hopefully I don’t bend the spacers first ride out (bad memories of coil DNM shocks on my old DH rig)