Why does my tubeless tyre keep losing pressure?

I have "inherited" one measly tubless tyre (mavic 719 with a Stan's system, I believe) which has been great but suddenly it deflates over a couple of days. I'm pretty sure it's not "burped" and can find no sign of tears, damage, leaks etc on the outside.

Does the gunky stuff lose its mojo after a year or two, or is something else likely to be needing replacing?

I sense this is basic 12 year-old stuff, but tubeless is up there in the "black magic" category for me along with cooking and maths.

i tend to put a couple of capfuls of stans wheel milk (or whatever its called) in each tyre every couple of months as it seems to solidify

Sounds like you need to top up the sealant (or maybe even take the tire off, clean it up and re-seal it).

Gooner – Member

i tend to put a couple of capfuls of stans wheel milk (or whatever its called) in each tyre every couple of months as it seems to solidify

do you clean the old stuff out? if not that will add up quite a lot

Maybe the tyre's not seated properly or got a hole in it that the stan's spooge doesn't seal coz it's gone off.

IMO the Geax stuff stays liquid for longer

What FuzzyWuzzy said ^^

Put an inner in it. Problem solved… 😉

Wow – lots of replies! Thanks guys. As I said, basuic stuff, but I can see I'll be topping it up.

Cheers

Out of interest did you inflate it with a CO2 canister or just a track pump?

Yeah. Where does the dried-out sealant go then ?.

Solo.

Does the gunky stuff lose its mojo after a year or two

A year or two! It dries up in a few months in my experience.

Sorry – away from the pc for a bit. I've been using a trackpump – it goes up OK but is then flat after a day or two.

Which sealant?