Have bought those little screw on gadgets to enable Prestas to be
air'd up with Schrader[normal]air pumps.

They all leak! I don't have much of a problem at the gas station
where they have a big compressor to pump the air, but I have 3 GREAT
air pumps, 2 battery pack and 1 cigarette lighter powered and NONE
of them can put in over 60psi without going DEAD!

So,I go to the bike shop, buy NEW Presta connectors, screw them on,
only to be greatly dissappointed once again!

This has been going on for over a decade now, so it'll be Schraders
til I can figure out how to pump the required 115psi+ into my
wheelchairs/handcycles....

ps: both of your replies were exactly the same as the knowledgable
folks at ALL the bike shops I've ever been too, they all agree with
you two, but I only wish I could duplicate what y'all have done!

Thanks again...handcycling forever:-)