Why is this tubeless leaking air?

[sethjs]

I noticed a slow leak in my new IRC RBCC Pros on the front wheel. I couldn't see anything obvious, so pumped them to 110 and sprayed on soapy water. The sidewalls seem to be bubbling on both sides in roughly the same spot. When I look closely, I can't make out any damage / punctures in that area. Just bubbles forming!

Here's a link to the video (I didn't do a great job but you'll get the idea). https://photos.app.goo.gl/5NqXWET45BNuSps99

Any expert advice??

Thanks!

[zefs]

How much sealant did you use? Could be that you need to help the sealant go around the wheel to make it seal better, try removing the wheel and rotate it through it's axis or go for a quick spin which also helps.

Also is the tape (if necessary) applied correctly?

[Geoff]

Interesting. It almost looks as though the sidewall did not get properly sealed at the factory. It is a bit strange that the sealant is not very quickly dealing with that, though. In my experience, lying the wheel on its side ina shoe, or something, so that the tire sidewall lies flat will ensure that the sealant gets right in there. Even if there is a factory issue between the threads of the caseing, the sealant sould deal with that in a few seconds.

[Orlok]

Fault in fabrication of the tire, so you need the contact your seller to change the tire for an other.!

[Aeo]

Some tyres leak a little bit in the area where the writing is, sealant should pick it up if you leave them on the side overnight.

[Marin]

Hold the wheel in both hands and rotate so the leaky area is at the bottom to make the sealant pool there. Then shake the wheel front to back so the sealant can rotate sideways inside the tire.

I will shake a freshly mounted tire like this, then rotate a bit, wait a few seconds for the sealant to collect, then shake again, for a full 360°.

[jfranci3]

Put the tire on it's side and give it a light spin. Let it sit for an hour. Repeat for other side. I bet it's the valve stem though. Tape a rubber glove over the valve stem area.

[TobinHatesYou]

Not a valve stem issue IMO. A leak at the valve stem would cause bubbling and sealant to appear at the spoke drillings in the rim, not on the sidewall of the tire.

This reminds me of my early complaint of IRC RBCC tubeless tires in late 2017. Both my friend and I experienced the same casing failure at the bead of the tire. The casing just split along the circumference of both our tires on his hooked rim and my hookless rim. I was using the Pro Lights, he was using X-Guards. The location and shape of the split casing made it unrepairable with DynaPlugs.

What sealant was used?

[AJS914]

Every tubeless tire I've tried so far does this. The two different Specialized tires I have on my mtb weep a bit through the sidewalls. I have Clement MSO Xplor tires on my gravel bike that haven't been great from a tubless point of view. In all fairness I don't think the Clement tires are the special tubeless version they now sell but I didn't realize there were two versions when I bought them.

[TobinHatesYou]

I don’t own any tires that weep, especially not after having ridden them a couple hundred miles like sethjs has. The sealant should have done its job.

[spdntrxi]

same here,, no weeps. I hope you are wrong about the MSO xplors.. because I just got some , but no weeps after 3 days.

[Orlok]

Every tubeless tire I've tried so far does this.

For more then 5 years now and 40.000km I rode with tubeless and tubeless ready road tires and never saw the sidewalls seem to be bubbling on both sides in roughly the same spot.

[TheKaiser]

Lightweight tires go pretty thin on the rubber, for obvious the weight and rolling resistance advantages, but that can lead to porosity in the sidewalls. I agree with ASJ914 that it is quite common, at least in the MTB side of things, in "Tubeless ready" tires, as they are intended to be used with sealant, so they have a tubeless style bead but the casing is often pretty much the same as a standard clincher, and the manufacturer counts on the sealant plugging any small holes. That is not so much with UST certified tubeless, as that standard required an airtight butyl liner layer inside the casing which had to be airtight without sealant (although people often did use sealant anyway for puncture protection).

Road tubeless standards (or lack thereof) are a pretty hot topic of debate, and at this point depending on the company, it can be a little tough to tell where on that spectrum of airtightness they fall, unless they explicity state it. Conti went the butyl liner route on the new GP5000 and so in theory they should be airtight without sealant. Early Hutchinson road tubeless tires were the same (although I'm not sure where they stand currently). Many other companies have gone for a very lightweight "Tubeless ready" clincher style casing, but are calling it some proprietary name of their own invention, so you kind of need to find out what their expectations are for sealant use in order to understand what they are really designing the tire for.

Practically speaking, I'd be surprised if simply positioning the tire as others have suggested, with sealant pooled at the point of leakage, didn't resolve the problem in just a few minutes. I have run into MTB tires that would continue to weep sealant slowly, even after initially sealed, but that was usually when they were run at very low pressure, so the casing was constantly flexing and creasing, which would keep opening up the pores in the casing. That was also on tires with paper thin sidewalls, where you are basically just talking fabric barely glued together by rubber. If the manufacturer intended them to be airtight though, then they will typically replace them so see if IRC considers this abnormal. If they send you a replacement, I'd just consider it a bonus, and I wouldn't hesitate to still ride your current ones, with a little extra sealant application.

[Miller]

I noticed a slow leak in my new IRC RBCC Pros on the front wheel.

How slow is slow, like, is that going down overnight or in a week?

Whatever, and although the leak probably is related to that bubbling, are you sure that the tape job and valve seating are fine?

[sethjs]

Update:

To answer a few of the question: Orange Seal was the sealant. I did add add'l sealant (~25 ml before this problem. Another ~25 ml once it started). It didn't start out like this - was initially holding air. And I believe the IRCs do have a butyl lining to make them full tubeless - at least they seem to hold air without sealant (in new condition) and it visually looks like there's a lining.

I took it to Spoke Easy (great shop in SF) - Anton sells IRCs (I didn't know - bought these from Cycle Clinic in the UK). We took it off. Crazy - the sealant was mostly gone. And we couldn't see any visible damage inside or out. Showed him the video. Total head scratcher. He said "I'd mount this tire if I didn't know".

So we mounted a new IRC RBCC Pro (went 28 this time). Holding air no problem. No work to tape or valve at all.

My best guess - I went an early morning (dark) and wet/rain ride and hit a few "invisible" sizeable potholes. Perhaps one of those damaged the construction in a way that we couldn't visaully see when the tire wasn't inflated. Hence roughly the same spot on both sides. But it's a bit of a mystery. Rear was totally fine.