Tubeless tribulations

For discussions about bikes and equipment.
cheesey_rower
Posts: 5
Joined: 18 Jan 2019, 2:11pm

Re: Tubeless tribulations

Postby cheesey_rower » 20 Jan 2019, 5:53pm

Still no joy. I used the Specialized Blaster and they tyre did go up - but there was no seal around the valve - even with the Schwalbe lubricant. I dismounted the tyre, moved it around a bit and had another go. I also tried three x consecutive inflations with the Blaster, just in case it had 'nearly' seated but not quite.

Further googling suggested that the wheels are difficult to initially set up with tubeless. I think the diameter of the valve and its profile, causes the tyre bead to not sit well, such that it cannot generate a good enough seal, so I am tempted to swap out the valve for one with an oblong profile on the inside of the rim, but that would mean going for a valve extender also, as it needs to be at least 60mm deep.

Brucey
Posts: 34874
Joined: 4 Jan 2012, 6:25pm

Re: Tubeless tribulations

Postby Brucey » 20 Jan 2019, 6:09pm

so is 'the leak near the valve' because

a) the valve is not sealed against the rim or
b) the valve assembly is not correctly put together (eg core loose) or
c) because the base of the valve is interfering with the tyre beads and preventing the tyre beads from seating somehow?

In the former cases (a / b) air will be coming out around the valve or the valve hole in the rim. In the latter case (c) the air will be coming out between the tyre bead and the rim, near the valve.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

cheesey_rower
Posts: 5
Joined: 18 Jan 2019, 2:11pm

Re: Tubeless tribulations

Postby cheesey_rower » 20 Jan 2019, 7:28pm

From the noise and the mounting lubricant behaviour, I think it is C. I have removed the valve core when trying to inflate, but the seal of the pump appears sound

Brucey
Posts: 34874
Joined: 4 Jan 2012, 6:25pm

Re: Tubeless tribulations

Postby Brucey » 20 Jan 2019, 8:34pm

use soapy water to be sure where the air is coming out.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

cheesey_rower
Posts: 5
Joined: 18 Jan 2019, 2:11pm

Re: Tubeless tribulations

Postby cheesey_rower » 27 Jan 2019, 2:36pm

The saga has continued - I recount the saga so others don't have to.

I got some DT Swiss tubeless valves and threaded extenders. Certainly the tyre inflated better, and I even got the beads to pop, but I didn't have an apparent seal at the valve - the air was leaking out of the relief hole. The Schwalbe Pro 1 was an absolute pain to get it to seat properly opposite the valve, but after a number of attempts it did.

I thought I would try a Stans tubeless valve - with threaded extender - as it looked like it would seal better with it's conical profile, now that I knew I could get the tyre to sit. I tried with this valve. Again, the tyre seated correctly, but still no apparent seal at the valve - air coming out of the relief hole, bubbles appearing at the valve's exit from the rim.

I decided to have a go with the other wheel. This time I inflated the tyre with an inner tube, and left it overnight - making sure that it the tyre was seated correctly. Today, popped in a Stan's valve, and with the Specialized Blaster the tyre popped into place first go..... but air coming out of the relief hole.

Possibly the pre-installed rim tape is not sealed, or the valves are not sealing - though checking the valve it seems to be seated fine, and it can't be tightened in any more than it already is.

Should the tubeless tyres be airtight with no sealant in them? Or are they dependent on sealant to provide the final seal?

My key lesson is to 'cure' the tyre with an inner tube first to push all the kinks out that arise from folding tyre storage.

I also found that one of the brand new tyres had a tiny hole in the sidewall - do tubeless tyre manufacturers check they seal before shipping - or is this again another instance of assuming sealant will handle small imperfections - therefore they do not need to check.

I can either try some aftermarket rim tape on top of the OEM tape, or just chuck the sealant in..
Last edited by Graham on 27 Jan 2019, 2:37pm, edited 1 time in total.
Reason: So . . . So . . . So . . .

Brucey
Posts: 34874
Joined: 4 Jan 2012, 6:25pm

Re: Tubeless tribulations

Postby Brucey » 27 Jan 2019, 3:27pm

good tubeless valves should seal first go onto good rim tape, with no sealant required. I suppose it is just possible that the valve is sealing to the tape OK but that the tape is wrinkled or something next to the valve enough to make the tyre not seat/seal properly, but anyway your setup may seal and work Ok with sealant despite not being as good as some.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

tincaman
Posts: 57
Joined: 27 Jun 2010, 9:41pm

Re: Tubeless tribulations

Postby tincaman » 29 Jan 2019, 1:51am

cheesey_rower wrote:The saga has continued - I recount the saga so others don't have to.

I got some DT Swiss tubeless valves and threaded extenders. Certainly the tyre inflated better, and I even got the beads to pop, but I didn't have an apparent seal at the valve - the air was leaking out of the relief hole. The Schwalbe Pro 1 was an absolute pain to get it to seat properly opposite the valve, but after a number of attempts it did.

I thought I would try a Stans tubeless valve - with threaded extender - as it looked like it would seal better with it's conical profile, now that I knew I could get the tyre to sit. I tried with this valve. Again, the tyre seated correctly, but still no apparent seal at the valve - air coming out of the relief hole, bubbles appearing at the valve's exit from the rim.

I decided to have a go with the other wheel. This time I inflated the tyre with an inner tube, and left it overnight - making sure that it the tyre was seated correctly. Today, popped in a Stan's valve, and with the Specialized Blaster the tyre popped into place first go..... but air coming out of the relief hole.

Possibly the pre-installed rim tape is not sealed, or the valves are not sealing - though checking the valve it seems to be seated fine, and it can't be tightened in any more than it already is.

Should the tubeless tyres be airtight with no sealant in them? Or are they dependent on sealant to provide the final seal?

My key lesson is to 'cure' the tyre with an inner tube first to push all the kinks out that arise from folding tyre storage.

I also found that one of the brand new tyres had a tiny hole in the sidewall - do tubeless tyre manufacturers check they seal before shipping - or is this again another instance of assuming sealant will handle small imperfections - therefore they do not need to check.

I can either try some aftermarket rim tape on top of the OEM tape, or just chuck the sealant in..


My WTB Exposure 30 TCS (Tubeless Compatible System) tyres were very porous to start with, after adding the sealant, it leaked out of about 50 tiny micro holes in the side walls, these mostly stopped leaking when I sloshed the sealant around.
When my valve hole leaked I repaired it over the top of the existing rim tape with a length of Gorilla tape about 6 inches long, tough and super sticky