AMoney

I am trying to do a tubeless install with a compressor. I was able to hear the loud pop, but the tire is immediately losing air. It seems like it is losing air from the valve stem. What am I doing wrong?

rosefarts

I hope you haven't added sealant yet. Just a test inflation. This sort of thing is exactly why you do a test inflation.

-Assuming you haven't added sealant.
Pull the tire and inspect the tape carefully Fix any issues you see, usually by replacing the entire strip. A leak can be either from the valve stem or somewhere else. Usually it's the valve stem. If you used some soapy water, are bubbles forming at the nipples too? If not, it's the valve stem. Make sure the connection is clean and tight. I find that pushing the stem in with my thumb until it hurts and turning the nut as hard as I can works. I'm sure you can devise a way to do this with tools if necessary. Now that you've got the tire off, lets be thorough and dab rubber cement around the stem. Put the tire back on and wipe some soapy water on the bead, inflate it. It should be better.

-If you already added sealant.
Pull the tire, try to save as much as you can, and do everything I mentioned above. Good chance that'll mean replacing the tape too.

Try to be meticulous about every step. Tubeless is one of those things that a little slop or cutting corners makes a huge difference. Go out of your way to make everything as clean and perfect as you can. Air finds a way out, even with sealant. A good job is the difference between barely holding enough air for a medium length ride and not being able to remember the last time you added air.

AMoney

I did already add the sealant. I also tried swapping valve stems to see if that helped. With one valve stem, I couldn't even inflate air. With another, I was able to seat it, then use a floor pump to inflate it to 60 PSI, heard multiple pops (both with the compressor and floor pump), and then it immediately deflated afterwards at the valve stem.

I should add that I was able to seat this same wheel and rim tape previously without any issues. The only thing that is new is the tire, though it's the same model as the previous tire.

SoSmellyAir

In my limited experience -- only with new gravel wheels and tires, and thus at lower pressures -- a perfect tubeless setup should be able to hold air well enough even without any sealant such that the tire deflates over a few hours rather than immediately.

What tubeless valves are you using? Is the grommet integral to the valve stem or is it a separate piece that slides onto the valve stem? In my limited experience with the latter type, I find that it is important to tighten the tubeless valve stem nut just right. Too loose, and it does not compress the grommet enough to form a seal. Too tight, and the grommet is deformed such that it would not form a seal.

AMoney

I have a Bontrager set of tubeless road wheels. I tried three different valve stems that I already have: Bontrager, Stan's, and Chris Kings. Not surprisingly in retrospect, I came closest with the Bontrager tubes. All three had a nut that I had to tighten on. I tried it with different levels of finger tightness but didn't have any luck.

downtube42

For me, it's always the tape. Always, always the **** tape. I take the rims to the wheel guy and he throws on tape like frickin' nothing, and it's perfect. Whereas I'm spending equal dollars wasting tape trying to get the stupid stuff to seal.

/rant

NVFlinch 

Watch this guy - he's hillareous, and he knows how to tape a rim. It's the tap, as previously said.

Tape: Throw away anything tape-ish that you have that does not say 'Scotch 8898' on it. Same tape the guy in the video uses. Use at least TWO wraps. Tape width should be the same+2mm wider than your rim internal width.

You'll get there!

Oh, and the reason the tires are demounting is because the tape at the outer channels is not thick enough and the new tires have a smaller bead than the old ones. It's the tape...

Canker

How bad of a leak? Usually I can fix a small leak at the valve simple by bouncing the tire with the valve at the bottom so the sealant splashes against the valve.

oldwinger14

If replacing the tape doesn’t solve the problem, there could there be a issue with the wheel itself. Perhaps the rush of air from the compressor is enough to seat the tire but once you remove the compressor, a slight dent or some other problem with the wheel allows the air to leak out.

oldwinger14

Did you forget to post the link or did I miss it.

NVFlinch 

Hmmm, posted but must have been stripped out. Here's the link again, YouTube, look up 'Riders of Japan', video = "Captain Tubeless: All about the tape" if the link is gone again.

You Tube

Mtracer

When you say it is immediately losing air, do you just mean it starts to deflate. Or in a matter of moments it is deflated?

I recently switched a wheel back to tubeless, It was a Bontrager wheel that uses the Bontrager rim strip rather than tape. I used what I thought were the original valve stems. These just would not seal well where they interface to the rim strip. The tire would completely deflate in say an hour. The air was leaking into the rim and finding its way out around the spoke nipples.

I then used some Muc-Off valve stems I had and these came with three different rubber seals for the stems. I used the one that was just a cone shape. So, it sort of fit into the hole. Sealed well, problems solved.

If it's deflating really fast, like a whoosh of air, then probably something is wrong with your methods. Are you having a massive brain fart and inflating without a valve core and forgetting that as soon as you pull the inflator off all the air will rush out the valve? Like I said, it would take a massive brain fart to not figure this out for yourself, but we all have those moments from time to time.

Off course, there's always a chance you have a defective tire. Unless of course you are certain the air is coming from the stem somewhere. And if it is the stem, there's really only two options Either the stem doesn't seat properly inside the rim (my problem), or the valve core is not sealing. Perhaps not properly tightened.

AMoney

That's interesting that you found that the Bontrager valve stem didn't match your Bontragers. I will keep that in mind (I'm also using Bontragers). I'm using the rim strips that came with my wheels. These are very difficult to remove and Bontrager recommends using them for tubeless. I'm not sure where the source of the leak is, but I think it is highly unlikely that it is coming from the rim strip.

Also, I use the Schrader adapter on the Presta valve stem and I don't remove the valve core. I saw sealant coming out of the valve stem even before I removed the compressor or pump, and it rapidly lost air after removing it. Since I was having issues, I did some research and saw that some people do what you described: remove the valve core, use the compressor to seat, and then reinstall the valve core. Should I do this next time instead of what I did?

Also, the only thing I changed since my successful tubeless seating was the tire, and even that tire is the exact same model as the previous tire.

choddo

I use those Bontrager rim strips and valves. I have removed the valve once before and cleaned all the dry sealant off it because it seemed a bit clagged up and I thought it might be affecting the seal.

Mtracer

I don't know for sure that I tried to use the original Bontrager valve stems, it's just what I thought. I could be wrong, so don't put too much weight on that. The real point is that the way the valve stem seats against the rim strip or tape or whatever, can matter. But it sound like you're losing air very fast. It seems like it should be pretty easy to track down a big leak. With a stem there's just two thing that can leak. Where the stem seats against the rim strip and the valve core. Unless there is something really weird about the way the core seats to the rim strip, I don't see how that could cause a fast leak.

But you mentioned it was hard to remove the rim strip. So, apparently you tried to remove them or did for some reason, The only way I know to do this is to work a small bladed screwdriver in the valve stem hole to begin to lift it up and out. Did you perhaps damage it to the point the valve stem can't properly seal against the rim strip? I would think the damage would be very obvious. If you think so, just order some new Bontrager rim strips. I really like them. They seem to seal well and they simply do not have the potential to fail like tape can. But as you said, they are hard to remove. So, best for a wheel you intend to setup tubeless and leave it that way.


It certainly seems possibly that a bad core or one that has a bit of sealant preventing proper closing of the valve could be the issue. So, I you have a good point. The OP should perhaps pull that valve core, clean it well and see if the problem continues.

Bradleykd

when you re-tape it, do a couple of things to help.

1. at the valve hole, don't just cut a X in the tape and push it through, take a round file and cut the tape off to the metal or carbon. You can do this with a hot awl or screwdriver too, but I'd only do that on aluminum rims. This is going to give the rubber on your valve stem a little better bite and seal.
2. put a tube in it.... I know. You want don't want tubes. Putting a tube in first will press all of the air out of the tape and stick it solid. Leave it over night, then pull one side of the tire off, pull the tube, install your valve, and dump some sealant in. That one side should pop back on no problem with a track pump.

Even if you don't re tape it, try these tips. I bet the valve is the issue.

I've never had an issue in 10 years of tubeless tires when I follow these two simple tips.

choddo

The Bontrager rim strips aren’t like normal tape, they’re a circle of harder plastic, shaped with a shelf, that snaps into the rim. Can’t remember if I punched a hole or had to align it first.

Mtracer

The hole is already in the strip it is also molded to provide a flat spot for the stem seal. You just have to align the rim strip hole with the hole in the rim.

alcjphil

since Hutchinson and Shimano collaborated to design road tubeless tires many years ago there have been many setbacks and breakthroughs. Some wheel makers have tried special rim tapes to improve sealing. Some others have relied on special rim strips to do the same thing. Some other wheel makers have designed wheels that do not rely on any rim tape at all. I was a bit lucky that my first tubeless wheels were of the last type. I never had to rely on tape to render my tires air proof. Now, many pro teams have eschewed tubular tires for better flat protection afforded by tubeless road tires. This tech is evolving since I tried my first tubeless road tires. They are much better now

yannisg

I have always had to tighten the valve using pliers so it seals completely.
Are the tires new? I have found used tires are much more difficult to seal even with a compressor to the point where I had to occasionally use a new tires.
I found that using a booster far more practical than a compressor.
Make sure you remove the valve core prior to the initial inflation. The valve core restricts the airflow