Very slow tubeless leak won't seal
08-10-18, 08:34 AM
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Very slow tubeless leak won't seal
After more than a year of tubeless bliss -- no issues -- I have encountered a persistent very small leak that simply won't seal. I can ride all day but the tire will have gone down from 60 psi to 40 psi and will need to be topped up. They are fairly large tires (700x40 Schwalbe Almotions) and I am a heavy rider hence the 60 psi.
The tires are tubeless-ready but the rims (Dyads) are not. The rims were prepared using tubeless rim tape and have a tubeless schaeder valve. They need steady pressure for an initial seal but after 5-10 seconds of dribbling they seal up well. I removed the tire and inspected it very carefully for embedded glass or other debris but found none in the three small tread cuts (1/4" max). There was no sign of the cuts on the inside of the tire but I nonetheless put a vulcanizing patch on the inside of the tire at the location of the worst cut and remounted it with new Stan's sealant and a new valve core.
Despite this the tire still seems to lose a bit of air and needs daily topping up. There is no evidence of sealant leakage. Any suggestions?
The tires are tubeless-ready but the rims (Dyads) are not. The rims were prepared using tubeless rim tape and have a tubeless schaeder valve. They need steady pressure for an initial seal but after 5-10 seconds of dribbling they seal up well. I removed the tire and inspected it very carefully for embedded glass or other debris but found none in the three small tread cuts (1/4" max). There was no sign of the cuts on the inside of the tire but I nonetheless put a vulcanizing patch on the inside of the tire at the location of the worst cut and remounted it with new Stan's sealant and a new valve core.
Despite this the tire still seems to lose a bit of air and needs daily topping up. There is no evidence of sealant leakage. Any suggestions?
08-10-18, 10:55 AM
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Air is coming out somewhere. Submerge it and look for bubbles.
I agree with @trailangel. If the rims are not tubeless ready then all bets are off.
Lots of guys run tubeless setups with non-tubeless rims however, and maybe someone who does will be able to help.
-Tim-
I agree with @trailangel. If the rims are not tubeless ready then all bets are off.
Lots of guys run tubeless setups with non-tubeless rims however, and maybe someone who does will be able to help.
-Tim-
08-10-18, 10:58 AM
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Talk to a plumber or a hydrologist. Obtain one drop of fluorescent leak detection/tracing dye. Put it in the sealant of the tire in question. Ride around a while. Examine the wheel and tire with a UV light.
08-10-18, 01:04 PM
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I had this with one of my rims. I injected a full bottle of Stans and let it sit in various positions over a day.
It lacked elegance but it worked.
It lacked elegance but it worked.
08-12-18, 01:25 AM
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Try two layers of tape on the rims. A single layer should be OK at 60 psi but if you hit a big bump, it might not be. If it is leaking at the valve, you can put a piece of tape over the valve to help it seal, cutting a small hole in the tape to let air in of course.
08-12-18, 06:51 AM
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Tubeless rims are a great idea but not currently in the budget. I will try the suggested leak-detection methods and replace the entire valve when the opportunity presents. In the meantime, I remain puzzled as to why the sealant won't seal such a tiny leak.
