I want to set up my tires tubeless. I got a Schwalbe Tire Booster and have a proper air pump as well. The booster is capable of holding up to 11 bar of pressure. I am not sure how much pressure I have to put in there to initally inflate my tire so that I seat the tires (with a pop). I guess there are differences for tire size as well. All I could find searching the net was a hint of a mechanic to not go over 40 psi.

I have a 650/47 tire and a 700/42 tire but for the community it would be best to have an answer that fits for all possible combinations like a list or so.

Anyone who can help out here?

  • 1
    No experience with tubeless here, but why not just go up to the maximum pressure? I’ve had to inflate (tubed) road bike tires to 7bars or more to get them to “pop” into the bead seat. Just make sure you stay below the tire’s and rim’s maximum pressure.
    – Michael
    Sep 18, 2020 at 7:28
  • 1
    Remove the valve core, clamp the chuck onto the stem and let off a burst of air. The bead should pop audibly into place. That's the way I've seen the mechanic do it at the LBS.
    – Carel
    Sep 18, 2020 at 7:47
  • Seating the tire is less a matter of pressure but of volumetric flow of air. Sep 19, 2020 at 5:42
  • Also, have you tried with just a regular floor pump? A lot of people are successful just vigorously pumping that. Sep 19, 2020 at 5:43

2 Answers 2


TLDR: The pressure you put into the bottle is NOT the pressure to which you inflate the tyre. The pressure drops down as the volume increases when you connect the bottle with the tyre. The final pressure you inflate your tyres to is mostly personal. There are some guidelines but depend on many details about the terrain and the tyre properties.

You ask for a list for various tyres. I do not think that is necessary at all for the reasons I mention - at least for the pressure of the bottle. Small tyres can withstand larger pressures and larger ones will not reach high pressures due to their volume. You can always try with 5-7 bar in the bottle, but the maximum the bottle allows should be safe for most tyres I can imagine.

If your tyre is above 40 mm, as you indicate, and of typical max pressure limits, you should have no problem using the maximum pressure indicated on the bottle if necessary. There are about 3 litres of air in the 45 mm tyre. The bottle has 1.15 litres. That means the final pressure in the connected system will be around one quarter. You may want to go lower in your first try, if your maximum tyre pressure is unusually low.

I use 10.5 bar (622-38 tyre with indicated max of 70 PSI) or slightly less when pumping becomes too hard with my body weight (but I want around 10 bar to be sure). You can of course first try if less will be enough for you. You may well be lucky with 5 or 7 bar, and it is dead easy to just try that first. Don't worry, it won't harm anything if you use too little. The only thing that may happen is that the tyre will not seal and you will have to try one more time with more pressure.

You will not reach that pressure in your tyre anyway. You distribute the pressure in a much bigger volume (bottle + tyre).

You first remove the valve core, connect the bottle and let the air in. You will then have to disconnect the bottle, put in the valve core (it is foolish trying to boost the tyre with a valve core - yes, I tried) and you will loose A LOT of pressure when doing that. After that you will have to pump up your tyre with a pump, because the pressure that remained will be quite low. It is only then when you care about the recommended pressure for tubeless riding in your tyre.

Nevertheless, when seating the tyre I go above the pressure I ride at (in the final stage with my floor pump). I let it first pump to 50 to 60 PSI. Then I ride at 30-40 PSI. The official range when using tubes is 45-70 PSI (3-5 bar) for my tyre but tubeless allows less.

For more general advice you can see other resources like How To Choose The Right Tyre Size For Gravel: From Road To Off-Road Riding but really, it is mostly trial and error on any combination of rims and tyres and there is a lot of personal preference involved. I like small tyres for comfort off-road. If you only ride on smooth tarmac you will choose higher pressures than if you ride on cobbles or on gravel. For road tubeless bikes I would be more careful about the range the vendor specifies, but for larger tyres it is really mostly trial and error. The more it is off-road, the more it is so. For mountain bikes you are looking for good traction and good suspension but at the same time you must limit burping.

A final remark: some tyres behave strangely. Mines (Schwalbe G-One Allround) are easy to seat using a floor pump when new. However, after several thousands of km, they became softer and it was not possible to seal them in any way and I had to buy the bottle. Now I bought a replacement for the front one - it was not possible to seat it with the booster, it was too stiff and when the booster was disconnected, it quickly unsealed. But it went easily with a pump. The old rear tyre, however, required the booster and was impossible to seal it with the pump...


On tires and rim combinations that were tight I have two that methods that seem to work well. The first is to inflate the tire to the maximum allowable pressure. Raise the tire and wheel about knee above the ground and drop it on to a hard surface. Catch the wheel when it bounces and rotate slightly. Repeat this all the way around the tire. If you hear the pop of the bead seating, adjust the tire to the proper pressure and your good to go. When that fails I will apply some liquid dish soap to the unseated area and repeat step one. If you have an issue getting the bead to seat initially to the point you can't inflate the tire Then try this method. Install the tire Take an extra tube place it on the outside of the tire. Inflate the extra tube until it distorts the tire enough start the beads to seat. Inflate the tire while releasing the air in the external tube.


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