Those 90degree valve stems won't work with spokes and tube tires
Probably one of HD's worst design flaws is the location of the rear valve stem on spoked wheels. Most air supply chucks won't fit on the stem and clear the spoke. I made this gauge and hose/chuck and with a Dremmell ground off some material from the chuck so it would fit. The gauge has it's own stem so I can clamp the chuck on the valve stem on the rim and add air directly to the gauge.