Squeeze

I had a new wheelset built for my Cross Check and, while I was at it, thought I'd try out tubeless tires. I read a lot and heard more good than bad so I rolled the dice. You guys might remember my thread about discovering the LBS put tubes in them instead, after I got two flats at the same time on my first ride. Anyway, they set 'em up tubeless for me after that and I haven't had any problems, until now.

I haven't noticed much difference with tubeless. I ride road and gravel and easy single-track. The bike isn't noticeably lighter or faster or anything, and I'm still carrying the same supplies and tools as I was before. But that's all fine. I'm not trying to complain but just learn something and maybe help those who, like me, read a lot of threads about problems they don't have yet or about components they're considering in the future.

I got the wheels and tires in early July and have been on perhaps eight or ten rides since then. I've had to add air to the tires before each ride and that hasn't been a problem. I've always done that with tubes, so I'm used to it.

However, it has been between two and three weeks since I've made time to ride. That is the longest the bike has been untouched with the new wheels and tires.

This morning I went out to the garage and pinched the tires. They were soft as usual, but not flat or even close to being flat.

I used my usual floor pump...



...and loosened the stem on the front tire. The valve started hissing, so I re-attached the pump a couple times, thinking maybe I hadn't unscrewed the valve all the way or didn't get the pump on straight or didn't move the "lock" lever far enough. You know - user error.

It kept hissing, no matter what I did, so I pumped fast and got it up to about 45 PSI, as recommended by the LBS where I had the wheels built. That was several hours ago and the tire is still holding air. However, I've never experienced hissing like that before with tubes.

The rear tire hissed also, as soon as I loosed the valve and attached the pump. I followed the same procedure, pumping fast while it was hissing, and it seemed good enough for me to stop and go back inside to finish getting ready for my ride.

When I came back, perhaps ten or fifteen minutes later, the rear tire was completely flat and I noticed the tire was not stuck to the rim as it should be.

I couldn't resist taking a peek inside to make sure there was actually sealant in there this time and not another tube. I could see some white, bubbly sealant in there, but not as much as I expected. I thought maybe it sloshed around in there like a pail half full of milk.



I tried pumping it up again, with the weight of the bike keeping the tire from popping back onto the rim, or so I assumed. Didn't work. Oh yeah...no tube! I can't leave the tire crushed under the rim like that.

So, I got out my repair stand and got the rear tire off the ground. I figured that was the problem. I pumped some more. I heard two separate popping sounds that I assume was the tire sealing itself to the rim again. I pumped with the valve hissing the whole time and got the tire feeling really solid and appearing to be bonded to the rim as it should be. The valve kept hissing after I removed the pump and the tire deflated and stopped touching the rim in some places within a minute or two.

I googled the problem and found this video. I followed the instructions about spinning and shaking and loosening the nut on the valve. I skipped the part about dunking it in water, but can do that if you guys think it's important. Nothing has changed. Perhaps I didn't shake the tire as vigorously as I could have. I did spin it a lot and tried to flip it around so the sealant might coat the area near the valve, but I don't know if that did any good. If I just need to shake it some more, I will.


The video is 2:13 in length.

The nut on the valve looked like this when I started - not super-tight, but finger-tight and touching the rim.



Per the instructions in video, I loosened the nut so now it looks like this:



The problem hasn't changed from doing these things.

There's just one more thing: when I have pumped up the rear tire (several times now), I've tried to figure out exactly where the hissing is coming from. I think it's coming from where the valve touches the rim, but when I put my hand around the tire so my thumb is on one side of the rim and my other fingers are on the other side of the rim, I thought I felt air coming from between the tire and the rim where the valve is - like in the middle of the white TERAVAIL logo in the pictures.

I don't know if that's really what's happening or maybe the air from the valve is just coming out at an angle I don't recognize due to inexperience. Maybe the air from the base of the valve is being reflected by the nut on the valve and seeming to blow "back" instead of "up" from the valve. Maybe I should put the wheel & tire in water after all, but it leaks so fast that I might get water inside the tire, and I'm guessing that's bad with a tubeless setup.

For what it's worth, I do have a brand new jug of Stan's sealant and a syringe from the LBS who built the wheels, but I haven't used them yet.

What should I do now?

cxwrench

Why on earth would you loosen the lock nut? The rubber grommet on the inside end of the valve has to tight against the inside of the rim/tape to seal. Tighten that back up and inflate your tire.
ETA: The link doesn't work for me.

Squeeze

The guy in the video says to loosen the lock nut and shows it clearly in the video starting at 1:00.


Hey, I think I figured out how to post the video. I was trying to use [video] tags as I do at similar forums, just like how I used [img] tags to post the pictures. It worked when I just pasted the link without any tags.

I think I'll go watch more videos about this...

Squeeze

I just did that. I tightened the nut so it was touching the rim and got it pretty snug with my fingers. I pumped it back up and heard a few pops as (I assume) the tire stuck itself to the rim again, but it is still hissing and going flat as I type this.

Also, I pinched the front tire. Remember how I thought it was holding air since this morning? Nope, it's very soft. Not completely flat and off the rim, but obviously not holding air. I put the pump back on it to check the gauge and the needle didn't show any pressure.

I don't know if this is relevant, but I didn't have this problem when I was riding it every couple/few days. This has started since I let it sit for two to three weeks.

ironwood

If the wheel has been sitting for a while, the sealant might have pooled in one spot. Take the wheel and hold it horizontally and shake it to redistribute the sealant, then flip the wheel and do the same.
As mentioned above in a previous post, make sure the locknut is tight. Also make sure the valve core is screwed in tight.
Putting the wheel in water can reveal any leaks.

After a couple of years with tubeless, I've gone back to tubes.

trailangel

Freshen the sealant up a bit....... (add more sealant) Do not loosen the lock nut that holds the value! Some tires just lose air. Maybe they didn't put any sealant in your tires... Have you checked?
In one of your pics, you broke the bead on the tire. You need to take the tire off and start over. Why you break the bead?

Squeeze

Yes, as explained and pictured in the original post.

Also in the original post - I inflated both tires with the bike leaning against something in the garage, but up on its wheels as bikes usually are. When I came back after getting ready to ride, the rear was completely flat and off the rim in places, just as it is now.

It seems to grab the rim again each time I inflate it and seems very solid for a minute or two, but then all the air leaks out from the valve and I don't know how to stop it.



I will try this. Thank you. I really appreciate the advice. This was unexpected since they seemed to hold air as well as tires with tubes do until today.

Edited to add: just curious; not arguing - the shop said to add more sealant in four or five months. I has been about six weeks. Did I get bad advice, or is this one of those "every setup is different" things?

TiHabanero

Ah yes, the joys of tubeless. Throw in a tube and go ride. Take it to a shop at a later date and have them try again.

Barry2 

Remove the core from the Valve stem and give it a clean.
At times the sealant gets boogers in the valve seat and they don't seal so well.
Run it under the tap and go at it with somebody else's toothbrush.
Then replace it in the valve stem and tighten.

Barry

Squeeze

6:00 PM my time - pumped up tires again after shaking wheels and gently working the stem around as shown in that first video I posted. I might have skipped through that one too quickly the first time I saw it and was wanting to go riding. 30 minutes later and they still appear and feel as if they're holding air.

Question: is it normal for a tubeless tire to pull away from the rim if the tire deflates from a leak while in a repair stand with the wheel off the ground?

Or, should it stick tight even with almost no air left inside, if the weight of the bike isn't pressing down on it?

cxwrench

1) The guy in the video is a moron. If you have a leak at the valve stem you don't fix it w/ sealant, you check the tape and the rubber grommet on the valve stem and replace one or both of them.
2) 3-6 months is was I tell people to expect.
3) Tire pulling away from rim? Maybe...maybe not. Some tire/rim combos are very tight, some are not. I've had to cut tires off of the rim because they were so tight on the bead seat. I've had some that just pop off the bead when deflated.
4) When installing tape I make sure the overlap of the tape is 180* from the valve and the tape is stuck down as well as possible. This will reduce/eliminate the possibility of air/sealant creeping under the tape and escaping out valve/spoke holes.

Squeeze

Original Poster here with an update about three months later.

I never could get the tires to hold air by myself, so I took them to a different LBS and paid them to set up the tires tubeless again. They did and the tires held air for a few rides in a few weeks. Each time before a ride, I'd add more air to the tires. I'm running about 45 psi in the rear and 40 psi in front.

Yesterday, I pulled the bike down from the ceiling hooks in the garage and topped off the air as usual. The tires were around 20 psi each but very much holding air and sealed to the rims. I added the usual amount of air and went back inside to fill water bottles and get my cycling clothes on.

When I returned, perhaps ten minutes later, the front tire was dead flat and dis-mounted from the rim due to the weight of the bike pressing down on it. This is the same problem I had before, as described in the posts above from August of this year.

What the heck am I doing wrong?

Koyote

This. You can buy a 10 pack or 12 pack of new valve cores on Amazon for a few bucks… I find that they need to be replaced every now and then in a tubeless set up. Takes just a couple minutes. I do it every now and then, when I notice a problem, when I’m topping up sealant.