This question is a follow up this question: Used tubeless ready tires leaking air (that were used previously with tubes)
I'm trying to get a 'working tubeless' system, and the pressure keeps dropping (10psi/0.5 bar per day).
I'm wondering if I missed some important step:
- the wheels are from Mavic and the tape was fitted in the factory. I used the valves provided with the wheels. The tires are tubeless ready, from Michelin.
- the tires were mounted without sealant. I could seat them with a foot pump, and heard the 2 "pangs" when mounting them. I inflated them till 4.5 bars before emptying them and removing the valve core.
- I initially followed Mavic recommendation for the sealant and added 45ml per wheel, shaked the wheel to try to spread the sealant, then went for a 5km ride on gravel. A note about the quantities: I didn't pay attention to a detail, Mavic's recommendation is for UST tires, which means "tubeless", not "tubeless ready", so the sealant is only used for punctures.
- following the previous question's answer, I emptied my bottle of sealant (that's 120ml in total), try to spread the sealant in the tire, then went for my 5km gravel ride.
- I repeated this step a few times, and now have 220ml in the 2 wheels (40mm tires), after having purchased another bottle of sealant (same brand).
- I went for a 20km "medium" MTB trail (pressure about 3bars), with loads of root and cobbles stones) in order to spead the sealant.
- I went for a 25km road/gravel ride (4 bars).
- I took a small nail, put it in the tire and removed it, to see if the sealant works, which it did.
- There's still sealant in the tires, and I'm only using a foot pump, no CO2.
After this, pressure is still dropping overnight. After spraying soapy water on the tires, it is possible to see that there are still many leaks through pores (see picture) — the front wheel is better, but not perfect. . Also, I spotted some leaks around some tires marking, that are still there (it's not new holes then). No bubbles are forming next to the rim's interface (bead and valve).
Is it normal, and if yes shall ride more (Schwalbe recommendation is 25km, I think I rode more...) or shall I keep adding sealant, or is it possible that the sealant is just not suited for this kind of tire (not fluid enough to get into the pores)?
After an additional 75km on rough surface and no progress on the "soapy water test", I decided to have a look inside. As pointed by Nathan Knutson and MaplePanda in the comments, there were serious doubts about the sealant used (Mavic, only certified for true tubeless tires, not tubeless ready tires). But in all cases, I got back almost 200ml of sealant. Strangely, on the other tire (front), the sealant was more evenly spread.
The second picture shows the inside of the tire after having passed a soft cloth (no rough cleaning then).
This can also go into Andy P's suggestion: the inside of the tire was not clean enough and the sealant could not attach itself to the tire.