Pah Bear Posted November 17, 2015 Posted November 17, 2015 If its leaking through the valve, sealant will not resolve the problem.
Meentb Posted November 17, 2015 Posted November 17, 2015 Most likely leaking somewhere on the rim tape. My brother in law had the same problem few weeks ago. Check that the rim tape is attached all around.
JXV Posted November 18, 2015 Posted November 18, 2015 I'm trying to do a tubeless conversion on my OEM Commencal rims. The problem I'm having is that there is a constant air leak at the valve stem. From some reading, I can figure out that it is either a leak at the base of the valve or there is air leaking into the inner rim cavity from somewhere else, which exits at the valve stem. I've put an extra piece of rim Stan's rim strip at the valve hole and fastened the nut nice and tight, but alas, no joy.The strip is also nicely installed (after a few attempts) and I can't see anywhere that the air might leak into the inner cavity. Also, there is a leak at the weld joint! Can that be patched up or should the rim be binned? I despise running tubes, so this is really damn annoying. Any advice?Leak at the weld joint is likely also the source of air exiting at the valve stem. This rim may not be convertible with rim tape alone. Using a sliced tube as combined liner and valve might be the next step if you can't get the tape to work.
Martin PJ Posted November 18, 2015 Posted November 18, 2015 My LBS owner told me to burn a hole in the rim tape with a hot match head, don't push the valve through the rim tape. Basically light a match, blow out the flame and then lightly push the hot match head through the rim tape. If you make a poor shaped hole, then the valve will leak. It won't seal because it doesn't get covered with sealant when you ride, the sealant goes to the outside of the tire. Also before you install the rim tape, clean the rim completely with meths or something like that.
GLuvsMtb Posted November 18, 2015 Posted November 18, 2015 Some more info: I haven't yet added sealant, as I first wanted to make sure I have a good seal. If I put sealant now, I'll probably just end up with a latex mess all over.2 things:1. Do it!2. Pictures (preferably a video) please.
PeterF Posted November 18, 2015 Posted November 18, 2015 There is a very good chance that sealant will stop any small air leaks that are occurring, even around the valve area.
Odinson Posted November 18, 2015 Author Posted November 18, 2015 Pumped the tyre to around 2bar last night and left it. It still had a fair amount of pressure this morning. I'm quietly hopeful that adding sealant might solve the problem.
jimmycool Posted November 18, 2015 Posted November 18, 2015 Sometimes The valve base doesn't seal nicely against the rim. I once had to cut a small rubber washer out of a piece of tube and put it over the valve stem before installing it. It did the trick and no more leaks around the stem.
mazambaan Posted November 18, 2015 Posted November 18, 2015 Be careful when you pump the tyre. I have found (15 minutes before the start of a race) that you can easily disturb the rubber seal to the tubeless valve and it cannot be restored by just tightening. So check that the seal is still in one piece without being torn or flattened and that it covers the valve hole completely when seated. Finally, put the pump head on carefully and try not wriggle the valve. Screw on types work best for this.
Odinson Posted November 18, 2015 Author Posted November 18, 2015 Eureka! Poured in some Stan's and shook/spun the tyre like a mofo and it seems to be working. No loss of pressure or Stan's spraying all over the place.
deanbean Posted November 18, 2015 Posted November 18, 2015 I had the same problem, a little bathroom silicone around the valve stem and it worked
BarHugger Posted November 18, 2015 Posted November 18, 2015 I had the same problem, a little bathroom silicone around the valve stem and it worked Boer maak 'n plan
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