Originally Posted by
bonsai171
It lost more air. The valve core was leaking pretty badly, so I tightened that. There were a few bubbles on the sidewalk, hopefully the sealant will take care of that. Left the house for a few hours, and it held the pressure pretty close to the original 40 psi. Gonna check again tomorrow morning, but it looks like this one is good now. Thanks everyone!
Dave
If the wheel does not hold air at least overnight, you may have a bum tubeless valve, or a tubeless valve with a grommet that is not providing a good seal against the valve stem and/or the rim bed. This may be due to under OR over-tightening the valve nut; the latter deforms the shape of the grommet. You could also try swapping valves or to a different-shaped grommet. My first time setting up tubeless wheels and tires was also a learning experience which required the guidance from my more experience brethren here on BF.
Noob Question re: Tubeless Valves - Bike Forums