Tubeless tires are seal-sealing against the bead of the rim... if the rim is in good, useable (smooth) condition, and should require no extra help from sealants. 

However, the primary leak point for the wheel is not the bead, but rather the valve stem. This since stems are exposed to abuse and age, while installed tires typically protect the rim's bead. Valve stem cores can also be re-installed loose or worn out. Secondary position is at the road surface, where you might have encountered a thorn or small nail. These can be impossible to spot from the exterior, and may require dismounting one side of the tire and then dragging a soft cotton cloth around on the inside. If you do discover a puncture, then a "hot patch" from the inside is the correct solution.

I suggest you start by inflating the tire up to 45 psi and then liberally apply a solution of VERY soapy water, using a common paint brush. Turn the wheel very, very slowly during the application, and you should see small bubbles start to appear at one of these areas. 

Hope this helps.

@wobbly I tried the soap and didn't find anything, but I am lucky to have a plastic basin and could immerse the wheel/tire. Sure enough there were about four spots where air was coming out - right at the edge of the rim and tire. The valve stem was fine. I attached a little movie. 

I'm going to remove the tire, really clean up the rim and hope to seat it completely this time. 

thanks 

yeah, the movie didn't upload. Here's an image.

If you're sure that the wheel wasn't submerged in Champaign, then you may have found your leak !!

What I've seen is that older rubber sticks to the inside of the rim keeping the new tire from making a seal. In those cases a Scotchbrite scouring pad was used to polish up the inside face of the rim and all was well. 

Sometimes the tire irons the shops use on their machines can kick up a burr (or you did in your early effort). Find and polish out,

I had the same problem. The rim likely needs to be cleaned up. After cleaning mine up it sealed.

Apparently, some soaps (that may have been used to help mount the last tire) cause corrosion so some research may be required to assure one of those is not used.

Just one of the "joys" of maintaining an older vehicle.  ? 

My wheel was pretty grodie when it was cleaned up the first time. It had rubber as noted above and some corrosion. The clean up worked for a little over a year and then leaks around the wheel/tire started again.

It was fine then flat. For those who have experienced this issue I suggest keeping a close eye on the wheel and tire pressure especially about a year after a first cleaning based on my experience.

It was significantly better this time with only "a couple" areas of corrosion according to the service tech.

My hope is the wheel/tire will hold pressure the life of the tire this time.

Happy Holidays!

Jack

It's important that you find out exactly what rubber lubricant your shop is using during tire mounting. When I started in the 60's, it was little more than a thick solution of soapy water. The pH of the detergents are such that they easily react with the aluminum. Looks great the first 6 months, then Bam ! corrosion sets in. What they should be using is pro tire lube for aluminum wheels, or maybe spray silicone.

Once you scuff through the anodized surface coating with 100 tire tools, you're automatically into raw, highly reactive aluminum.