I joined this forum because I needed information on the Nitrogen charge (Pressure) in the 748 rear Shock.
When I found members were talking about charging the shock with Air I became very Alarmed..
I am a 30 year Aviation Mechanic with 90% of my experience in Hydraulics. Both, Self contained (suspension Systems) and Dynamic (pump charged constant supply and pressure)
The common Reservoir Shocks found on modern rear suspension contain either a piston type or a Bladder type accumulator.
This Accumulator is the Gold cylinder attached to your shock.
The Accumulators job is to keep your shock oil under constant pressure While keeping the oil and Nitrogen separated.
As use wears the parts, i.e. O-rings on the piston or deteriorates the rubber bladder in the Accumulator
oil enters the Nitrogen side of the bladder..
Not a big problem, just means things a wearing out..
NOW THE IMPORTANT STUFF
Nitrogen is inert.. I contains no Oxygen. Oxygen being one of the three
things you need to make FIRE
. Take away Oxygen, fuel or heat and you get no FIRE
DO NOT PRESSURIZE YOUR REAR SHOCK WITH AIR.
Air contains 20% Oxygen. the oil in the shock is usually petroleum based ( a little bit heavier than #2
Diesel) Diesels ignite because of Compression.
If Air ( the stuff we breath) is used in the accumulator of the rear shock, You have a potential Pipe bomb under your seat.
Consider this... You're out for some spirited riding. The suspension is working hard, compressing and expanding all morning.
The day is warming up, your shock gets hotter with every bump.
The oil that found its way into the accumulator in getting atomized, a fine mist.
Your and you fabulous Italian engineered beast hit a pot hole, the sudden compression drives the air temperature into the realm of lower compression diesel engines
You have know clue what happened. all you heard was a loud bang. You and you machine have parted company.
This phenomenon is called Hydraulic Dieseling
OSHA has incidents on file, can be found on line.
PLEASE DONT USE AIR TO CHARGE YOUR REAR SHOCKS
NITROGEN IS INERT. THEREFOR NO FIRE OR BIG BANG UNDER YOUR SEAT
NITROGEN ISN'T USED BECAUSE ITS LESS PRONE TO TEMP CHANGES... IT'S A GASS, SQUEEZ IT AND IT GETS HOT, EXPAND IT AND IT GETS COLD.
Hope this helps all here.
Now I'm going to search for the info I need.
Have a great day...