Tubeless tires are great, until they aren't. When you first get that set from the shop you can't believe that you rode with tubes for so long. Then you have a blowout down the road, or you just need to change your tires. Everything is nice and smooth the first time, but here are a couple of extra tips to help in putting new tires on older wheels.
First, when you take off your old tires, there will still be some fluid in the bottom of the tire if you are lucky, so try not to spill that all over the floor. Generally in Austin you get ~4-6 months in cooler weather, but in the summer you may need to top off every 60 days; 30 if you ride a lot.
After taking the tire off, the first thing to do is look for the valve stem on the inside of the tire. These are notorious for getting clogged, and it makes pumping them up a lot harder, so find the valve and carefully clean out anything that might be obstructing the air passage. I like to use an ice pick.
Next wash off your wheels with a hose and then carefully dry them off; you really want them dry for this operation. I take a rag and make sure that I carefully wipe down the inside of the rim where the bead of the tire will be hooking up.
Once you have that dry, you will probably notice a lot of old latex residue on the inside of the rim. You'll want to clean off any of this that could get in the way of the bead of the tire seating properly:
If you look at the picture you'll see a glob of old latex. This will prevent the tire from hooking up properly. I like to use a plastic tool to try to clear as much of this off as I can. A tire lever works in some cases. Stay clear of anything metal. You don't have to get all of it off, but get as much as you can and make sure that the chunks are off.
Now, pull the valve core. Below you see my core and the tool that I use to take out the core. It's a $2 tool at most shops. Buy 3 or 4. Put one in your camelback, one on your workbench and then have 2 to give to people (someone always asks.) Nice people will give you a beer for being helpful...
Open up the valve core and clean off any old latex that is on it. This is another thing that will cause you headaches down the road.
Now the easy part. Mount the tire. To keep things clean, I mount the tire first without any latex in it. Inflate the tire until the tire hooks up on the wheel and it holds air. I have been able to successfully do this with a floor pump some times, but, honestly, having an air compressor is so much easier.
Once you have the tire on and it is holding air, take the core stem back out and fill in your latex. I bought the Stan's syringe, which attaches right to the presta stem. (if you don't have a syring, just pour it in the tire.) Attach the syringe and turn the wheel around so that the valve is at the top. This causes a bend in the syringe tube which is perfect for filling it:
I don't bother with the plunger on the syringe, I just flip the wheel around so the stem is at the bottom and let gravity take over.
Now at this point you have a seated bead, you have sealant in the tire and all you need to do is take off the syringe, put the valve core back in and inflate the tire. Because your bead is seated, you could either use a floor pump or a compressor. I like to get the tire up to ~50lbs. You typically hear a "pop" at this point as the tire is totally on the wheel.
Then pick up the tire and shake it a bit. Listen closely to see if you hear any air escaping. If you do this is common, just move the wheel around until this spot is at the bottom of the latex pool inside the tire. That typically helps close them up. It is a good idea to let them sit on their side a bit, shaking them again and then flipping them over to get the latex to coat the inside of the tire. The best thing you can do to break the tires in is take a few laps around the block on your bike. This helps to seat and work in the tire.
An additional tip from Layton: After you clean and remount the tire, apply some soapy water around the bead. In the Stan's video online, they use a bucket and brush, but I use the same spray bottle with Dawn and water that I use to clean my bike. As mentioned before, it helps the bead slip into place. Then, it makes big soapy bubbles on the areas that need a little more attention.