I’ve resisted tubeless up to now due to perceived faff, but my new bike came with tubeless ready wheels and tyres (WTB TCS wheels and Wolverine tyres) so I thought I’d give it a go.

Got some Stans valves and sealant, put them in and the tyres inflated no problem with a track pump and 75ml of sealant. Bounced the tyre around and left overnight with no pressure loss, went out for a shortish ride, no problem and I liked the feel of them.

Then today I went for a longer ride. Tyres pumped to 30psi, then about 3 hours in the rear goes soft. I thought maybe it had burped so I pumped it up and it went soft again immediately. So I examined the tyre expecting to see a small hole with the sealant trying to seal it – nothing. Then it was clear the air was coming out between the rim and tyre and the spit test showed air leakage at several points around the rim. I tried shaking the sealant into those areas, but it wouldn’t seal. Had the pressure up to around 50psi, but still no seal. The rim is undamaged.

Eventually in the rain and midges I broke the bead off – still loads of sealant inside – and put a tube in.

So what went wrong? Not had a puncture on the trail in 2 years so not really impressed with the whole tubeless reliability and lack of faff…

Did you fit some tubeless rim tape? No mention in your post.

The wheels come with tubeless rim tape already fitted.

Tubeless is really good. Assume this is your rims http://www.wtb.com/pages/tcs

Could be you need tape? If not then they weren’t seated fully. I use a couple tops of stans, don’t skimp, pump to 40psi. You sometimes hear a loud crack as they seat fully. Leave overnight. Reduce to 20psi go ride

Also check the valve is fully seated and has a rubber o ring between it and the rim.

My gut feeling is that they weren’t fully seated

Both sides seated with a load crack when I inflated them and today when I took the tyre off to get the tube in, it was quite hard to break the bead. They had been inflated for 10 days and an hour long ride with no loss of pressure until today. Then the rear just went 3 hours into the ride.

Really at a loss to explain it…

Try giving the tyre beads and rim a clean with soapy water to make sure there is no grease or mould release agent left that’s stopping the stans do its thing. Once you inflate try leaving the wheel on its side (lay it on a bucket) and sloshing it a bit to help the sealant get into the bead.

Take it off, clean it up and reinstall, you can probably salvage 95% of the goop. From the description I would say possible freak occurrence.

I have a ghetto set up upfront and that broke it’s seal the other week for no clear reason. Similar to you bubbles all around. The setup had done over three months unmaintained other than an odd top up

Deflated it completely, wiped the rim clean (ooo er) and a big blat of air and is now sitting comfortably again.

Was the sealant new? Did you give the bottle a good shake?

Maybe check the rim tape, and replace it with some stans yellow tape.

I always put over 100ml sealant in,shaken up really
really well, might help? What wheel size and the volume?

“The wheels come with tubeless rim tape already fitted”

Can you post a link to your bike. A lot of tubeless ready wheels refer to the rim and not the rim tape.

Hope hoops with stans rims used to come with standard rim tape. They now just include it with the box.

Might be worth popping into your lbs to see if they can help.

Yep reckon the tape is prime suspect.

My tubeless ready superstar sentinel wheels came with rim tape but it wasn’t tubeless rim tape just the normal stuff as I frustratingly found out!

Swapped for some schwalbe tubeless rim tape (expensive!) and all ok now.

Could be the tape, if it was stuck down it might have taken a while for the sealant to get underneath it to create a leak.

Also, ‘bounce the wheel round to slosh the sealant’ – hold it at 3 and 9 o clock, shake it so the sealant sloshes up over the tyre sidewall and rim. Then turn the wheel a couple of inches, and repeat. You may need to pause to let the sealant pool at the bottom every now and then.

If the sealant was up over the sidewall/bead, you’d have seen it bleeding through to seal the tyre before you got to the spit test.