I'm about to change the worn damper body on my Monarch RT3. I've watched the SRAM video and everything looks straight forward enough. I just though I'd check the pressure in my current damper body so I inserted the SRAM adapter and as I did it let out a fair amount of air. I added more air until I was back at the recommend 350psi but when I unscrew the adapter I lose loads of air. Is there a knack to this?
I know when you pump up the air chamber in the shock you always loose a bit of air but this is loosing loads. When I re attach the adapter I'm down below 250psi.
any ideas?
cheers
The problem is the chamber you need to pressurise is very small so any loss of air when removing the pump causes a large drop in chamber pressure. I read about people modifying the adapter with a thin length of plastic inside so the adapter itself doesn't release any pressure. Instead when the pump is attached it pushed the length of plastic into the valve core. This makes it easier to remove the pump without loosing pressure. It worked for me.
Sorry to butt in, are we talking about the IPF valve guys, that usually has nitrogen in?
Thanks for the reply, yes from the factory it comes with nitrogen but works fine with air.
Mjsmke where does the thin plastic ( tube I'm guessing?) go, though the center of the adapter?
cheers
Just found this thread
going to give that a try tomorrow
Ah, I've read about this problem.
I think there was a thread or more on pinkbike about it?
Ah! Nice find op!
Windysurfer, that should work fine. The adapter isn' a great design and lets out a lot of air before it' screwed in fully. I just drilled through with a 3mm drill bit so it didn't press on the valve core. Then a thin piece of plastic (Or metal) that goes inside the adaptr so when the pump is screwed on it pushes on the valve core just before it goes tight enough to seal.
^^ Got a pic of the bit of plastic in place as you mention?
I did mine the other week. Got the adaptor and the shock needed 500psi in, I was ready for a new shock pump so bought a cannondale airspeed. The valve has a thumbscrew style mount to unscrew it and it has a separate knob on top of the screw in part that is designed to disengage the schraeder valve pin before you unscrew form the valve. I realise the second part doesn't apply when the IFP adaptor is fitted but it worked well. I reattached the pump to check and it only lost a few psi when I did.
This is the one.
https://qwertycycles.co.uk/products/cannondale-airspeed-shock-pump-1mp01
Got a pic of the bit of plastic in place as you mention?
This was from another forum. Once the adapter is drilled out to make the bore wider, the bit of plastic fits inside which presses the valve. A bit of trial and error is needed so it presses the valve just as the shock pump is tightened up.
Old spoke cut to length works a treat .