I’ve used a mountain bike shock pump to top off my shocks.  Works perfectly.  In fact, I ordered one just for the plane this spring.  Got one that has doohickey that backs off the valve while still sealed, thereby not losing any pressure during the removal process.  The last few strokes are kinda tough to get 300 PSI but it does work. 

 

Nitrogen is preferred, but I’ve yet to find a shop that gets accurate (even +/- 50 PSI) with their big valves and gauges.

 

Matt

 

 

Ian,