Tubeless newb

Helped my friend buy a bike with tubeless tyres, and he got a slow puncture on his first ride. I have not been able to find the puncture, and have added around 60ml of sealant. I believe the tyre is still losing pressure slowly, without even being ridden on. How do I go about identifying the fault? I seem to have bad google-fu and haven’t found anything relevant on the internet, which tells me that I am not searching very well.

Thanks for any pointers anybody can give me. It’s going to the LBS today if I can’t figure it out, but I feel pretty embarrassed to be so clueless about it.

Did you put the new sealant in then shake the wheel around? Need to spread the sealant all around the inside.
Other than that, get a tub of water and see where the leak is.

I spun the wheel slowly, but didn’t really shake it side to side etc. I will try that and inflate it again. Tub of water will be the next step. For some idiotic reason i didn’t think to do that with tubeless. Foolish of me. Thank you so much for taking the time to reply and help.

See from about 3.50 in this video: Stan's Notubes Tubeless System installation - YouTube

(1) hold the wheel like a steering-wheel, shake it forward/back
(2) spin it about 1/4 way around, repeat shakes, then repeat until you’ve done maybe 2 revolutions of the wheel
(3) lay it flat on a bucket so the sealant spreads evenly around, leave it for about an hour
(4) repeat the whole process, then lay it on the bucket on its other side

That should seal up any small holes.

Also, is it properly seated? Pump it up to max pressure, see if you hear any pops as the bead seats.

What they said ^

Also add, some tyres can just leak slowly until little holes seal up (unless it’s during a ride I dont worry about it), or sometimes tape job is not 100% and leaking through spokes.

do the wheels use tape? if so, maybe the tape isnt down properly? i had a similar issue, so retaped and installed a tube and let it set for a few days, then took the tube out and reinstall

Hi folks,

Humbled by the level of help. This wheel is from a brand new Giant, so I would expect (but perhaps shouldn’t assume) that the tape is ok. I followed instructions 1 and 2 from diddy (and heavymetal) this morning but my friend has now taken the wheel home. I have sent the instructions to him and we shall see what happens!

You’re all lovely. Thank you, sincerely.

another easy one to check is the tubeless valve itself, between the rim and valve. Sometimes the o-ring dosnt sit right, maybe not tight enough or too tight and squishes the o-ring out of place. Quick spit/soapy water and check for bubbles

Thanks Jase. Going tubeless seems like hard work!

Well, once you get it seated with a compressor and sealed as described above, and then keep the sealant topped up, and figure out how to deal with punctures that don’t seal should you get one on the side of the road, it’s really no work at all.