SEATING THE BEADS

And what to do when it doesn't work
So far I have had 100% success rate setting up tubeless tyres at home without any special tools, such as a booster pump. My equipment consists of a regular floor pump, a valve core remover, some tyre levers and a recent addition - an inner tube! Not all tyres were easy to work with though. The last set of Rene Herse Hurricane Ridge 42's was a real challenge that triggered this post.

The only real difficulty of a tubeless setup is to seat the beads of the tyre on to the shoulders of the rim. By design this can only be done by applying sufficient pressure from within the tyre. What you do normally is put the tyre on and start pumping. With enough airflow the tyre starts expanding and the beads literally pop into place one after the other. After you hear those two pops the rest of the process is quite hard to fail, but this step in particular may cause you a lot of trouble. The underlying problem is that the air is escaping the tyre faster than you are pumping it and therefore pressure does not start to form inside. Here is a quick summary of remedies that I tried to date and that worked 100%.
The easy stuff that will solve ~80% of cases:

  • Check that the valve is inside the tyre. It may sound stupid, but it is actually quite hard to spot when it is not.
  • Remove the valve core to increase the air flow.

When you come acorss that tyre that just does not inflate no matter what, here is a fool proof method:

  • First, fully assemble the whole thing using a tube. This will seat both beads on the shoulders.
  • Release the air, fully unseat one of the beads by pushing it inwards along the circumference and then use the levers to get it out of the rim. It is cruicial that the other bead remains fully seated on its shoulder.
  • Remove the tube and install the tubless valve
  • Starting from the valve begin putting the loose bead back in place with your hands. Work away from the valve equally in both directions until you run out of slack. This will partly seat the bead on the shoulder and so you will end up having pretty good seal for about 60-70% of the circumference around the valve. However, if the valve will be positioned within that unsealed 30-40% section then the whole point of the exercise will be lost, as air will not get trapped at all.
  • Use the levers to finish the job. It will inflate and pop now.

Finally, here are some subjective stats on the various combinations that I have set up in the past: