I was recently frustrated when mounting a pair of tubeless tires. I couldn’t get a good seal on the valve stem and air was rushing between the bead and rim, never getting close to seating. I wanted to buy a tool to make this job easier, but couldn't find one that met my criteria. I foolishly decided to assemble my own from parts.

Here are my design constraints:

The air delivery system can be operated with one hand, leaving the other to grip the tire to assist the bead to properly seat
The maximum air pressure is limited so tires aren’t exploded
The mechanism seals well to a Presta valve stem with the valve core removed

This is what I came up with:

Here are the parts I used:

Air hose fittings 1/4" NPT x Industrial Type D (10 pack) : $29.95
Short 3/8" air hose (3 feet) : $14.99
Long 3/8" air hose (15 feet) : $16.16
Push button air valve 1/4" NPT : $10.85
Inline regulator 70-120 PSI 1/4" NPT : $19.95
Air chuck for Presta/Schrader valves : $29.95

Total parts cost is $121.85 without tax.

Is this a ridiculous amount of money for an air filler? Yes, it is.

Does it achieve all the design goals? Nope. It does not.

Does it work? Yeah, it actually does. Here’s a video show it in use (please accept my apologies):