SoSmellyAir

Is a tubeless valve supposed to leak air without any sealant?

After (1) popping the tire beads in place with a compressor, (2) replacing the valve core without adding any sealant, and (3) inflating the tires to just over 45 psi, I can hear and feel air hissing out from the Presta valve hole alongside the tubeless valves. I can change the rate of the leak by pushing the tubeless valves side to side.

Isn't a properly setup tubeless tire supposed to hold air at least temporarily even without sealant? Do I have leaky valves or do I just need to add sealant?

tyrion

My valves didn't noticeably leak when there was no sealant.

Is there a nut holding your valves in place? Are your valves' rim interfaces conical or cylindrical?



Conical: left, cylindrical: right. I've always had conical style. I've heard (on the internet) the cylindrical interface is more problematic.

SoSmellyAir

Thank you for responding. Yes, I am using a nut over an O-ring hand tightened to pull the base of the valve against the inner surface of the wheel. The base of the valve has a conical gasket.

These are the valves I am using: Amazon.com : Terske Super-Strong Black Titanium 44mm Tubeless Presta Valve Stems with Oil Slick: Light & Serviceable : Sports & Outdoors

I guess I will just try other tubeless valves. Any recommendation? The Muc Off original version is available for a semi-reasonable cost.

masi61

How perfect is your tubeless tape job?

SoSmellyAir

These are brand new Roval Terra CL wheels with tubeless tape applied by Specialized. The application looks good, with no air bubbles, and definitely better than the tape job on the stock wheels, which does have some air bubbles under the tubeless tape, but held air fine.

Update: Front wheel is holding air but noticeably lower than 45 PSI; rear wheel is not holding air at all. Have order a pair of Muc Off V2 valves to try.

Koyote

https://www.amazon.com/Stans-No-Tube...%2C124&sr=1-16

SoSmellyAir

I cancelled the Muc Off ones and ordered a pair of Stan's 55 mm valves (mostly because they can be delivered tomorrow instead of next week).

dsaul

The valves need to be very tight to stop them from leaking. Simply finger tight is not going to do it. I press on the rubber part with my thumb, while tightening the nut with my fingers. When I'm finished I have a dent in my thumb from pressing the valve into the hole. When you think its tight enough, press harder and tighten it another half turn.

Koyote

I disagree with this. It may make it impossible to remove the valve for a roadside tube insertion. Standard “finger tight“ is good enough.

staehpj1

Well, I'd argue that maybe it isn't tight enough in this case since it is leaking there and there is no obvious issue. The rubber whether conical or cylindrical does need to get compressed a little. How much? Enough so it doesn't leak. I would suggest maybe tightening it until it doesn't leak and later backing it off and retightening it finger tight after it is seated in good if that worried about being able to get the srem out later on the road/trail.

Koyote

I wouldn’t be doing anything differently until putting in the sealant.

Canker

It isn't uncommon for air to leak around the valve. I'm just going to copy and post my own post from yesterday in another thread.

The trick if it does leak is to hold the wheel so the valve is at 6 o'clock and bounce it off the ground a bunch to splash sealant onto the valve.

SoSmellyAir

I had pressed the valve base down into the rim bed as I tightened the nut, so it is pretty snug.

I was concerned that if I add sealant it would just spray out of the Presta valve hole all over the wheel and garage floor.

SoSmellyAir

Even the front tire was just about completely flat this morning.

But the Stan's 55 mm tubeless valves seem to have solved the problem! Thank you, Koyote!

At first, I was not too hopeful, because the rubber base of the Stan's valves could barely be pressed down into the Presta valve hole. The rubber base was noticeably firmer compared to the prior Terske valves. But I persisted with installing the Stan's valves and there was no audible hissing or discernible leak around the valve stem after I inflated the tire to about 45 PSI. After about an hour, both tires are noticeably softer, so they did lose some air; but at least I feel comfortable adding sealant tomorrow.

SoSmellyAir

Stan's videos say that, for a first time tubeless setup, one may have to add more than the standard 2 oz. / 60 mL How much more?

For reference these are GravelKing SK 700x38c (ETRTO 40-622) tires mounted on wheels with an internal width of 25 mm.

Koyote

I think it depends on the tire. Thinner sidewalls are usually more supple, and sometimes more porous, and so some sealant is absorbed in order for them to become airtight -- in other words, it's by design, and hence it may take a larger initial dose of sealant.

With 38mm GKs, I'd recommend that you start with 2oz per tire, and take time to do it right. Then remove the valve cores in a week or two to see if your sealant levels are okay, or if it needs topping up. Check it by dipping in the provided dipstick; if they didn't provide one, use something long and skinny like a stiff zip tie. Basically, if you see about 1/4" of sealant on the bottom of your dipstick, you're fine.

Hopefully you've watched some videos on setup tips and tricks, so you'll know what you're doing. SHAKE the sealant vigorously for at least a minute before putting it in. Once it's in, hold the wheel horizontally and slowly turn it in a wobbling motion to cover the lower (facing the floor) sidewall with sealant -- imagine that you're painting it with sealant. Then flip the wheel over and do same on the other side. Feel free to give it some shaking, too. Then rest the wheel horizontally over a bucket (set it gently with the hub in the middle of the buckets top opening, so it's resting with the spokes on the bucket's edge), so that sealant pools up on the lower (facing the floor) sidewall, and let it rest like that for a few hours...Then flip the wheel over, slosh the sealant around again, and let it rest on that side for a few hours. Make sure that there is plenty of psi in the tires, so that the sealant will be pushed anywhere that needs sealing. Do all of this for both wheels -- and then when you mount them, they should be pretty airtight.

SoSmellyAir

Koyote Thank you for the detailed instructions. I plan to do what you described above and during that, Canker's tip about bouncing the wheel with the valve stem at the 6 o'clock position. Searching for a round bucket or barrow now.

Koyote

Doesn't have to be a bucket, I suppose -- just something that will support the wheel in a perfectly horizontal position. Could even be a couple of wide-mouth drinking cups or glasses, though those will obviously require a bit more care when setting down the wheel.

I've found that with careful setup like this (I repeat the shaking and such several times, and sometimes leave the wheels on the buckets for 6-8 hours per side), and with decent tires, I usually (not always, but usually) end up with tubeless setups that hold air about as well as tubed tires.

rosefarts

My first setup or two had problems with the valve just like you describe.

I get higher quality valves, no off brands. I put them in really tight, yes, by hand but really tight. I’d be able to get it off roadside but it might hurt my fingers a little.

I dab rubber cement around the valve to fill in anything that may leak. I don’t know that this works, but I don’t know that it doesn’t.

Using a rag with soapy water, I brush the sidewalls and get them nice and wet. I then massage the tire out of the center channel. With all this done, 90% of the time it’ll inflate with a hand pump. I usually let it sit for an hour or so to make sure it doesn’t leak.

I add sealant through the valve with the core removed. Letting out the air to do this won’t break the bead.

The final piece is to grab the valve stem firmly before opening up the valve, to prevent any twisting of the stem, which can lead to a leak. Do this every time you air it up or add sealant.

FWIW, I add air every few weeks. My tubeless setup leaks way less than tubes.

SoSmellyAir

I found a ceramic pot which looks like it has a perfectly level rim when sitting on the ground. I also bought a bottle of Orange Seal as I read that it is better for initial setup because it more readily forms a layer at the bead interface.

I have further tightened the valve stems by orienting them at the 12 o'clock position and pulling down on them while tightening the nuts. My fingertips are very sore; I am not sure I would have enough fingerprint left for Live Scan.

I set the tire beads with my compressor. After a couple of loud pops per tire, the tire beads look very well seated all around. After that I replace the valve cores, then inflate to 50 PSI. Without any sealant, after an hour or so, the tires still hold air but are noticeably softer, but at least no audible or discernible hissing from the valve stems, so an improvement over the situation that led to my first post. Are the wheels, tires, and valves ready for sealant?

SoSmellyAir

KOM injector does not fit through Stan's valves. Muc Off it is.

Koyote

After setting the beads, you can add sealant immediately. There is nothing to gain from letting them sit around without sealant.

Not sure what's going on here. All valve stems should have the same diameter for the opening (with the core removed). Also, the KOM injector should come with a tube that fits onto the open (core removed) valve stem, not in it.

SoSmellyAir

I bought this injector: Amazon.com : KOM Cycling Tubeless Sealant Injector Syringe and Presta Valve Core Removal Tool by Designed for Stans No Tubes sealant and Other sealants … : Sports & Outdoors

It is designed with a thin straw that goes through the whole valve stem and extends past the rim bed to inject sealant, which is supposed to reduce clogging of the valve core, but does require a valve with a wider opening at its base. The thin straw fits through the previous Terske tubeless valves, but not the Stan's.

Koyote

Yeah, that’s the one I’ve got. I believe you can separate off part of that assembly and just inject sealant through the top of the valve stem. It doesn’t really lead to any clogging that I’ve noticed, at least with orange seal. But you can probably inject straight into the tire, as you described, with the valves you’ve got now.

Just a tip: make sure to rinse that injector out pretty thoroughly after use, and run water through the tip assembly, too. Otherwise it will clog up with sealant. Ask me how I know. 😀

SoSmellyAir

Koyote Good to know. That will be my fallback position; cannot just keep buying tubeless valves.