Ever had a tubeless valve refuse to seal?

I’ve got one and I’m at my wits end with it, it just refuses to seal up! Its a brand new 29er Hope rim, that’s just been built up with Stans valve. I’ve inspected it and can’t see any cracks or such like. I’ve taped it up twice, and changed the valve on the off chance it was faulty (it wasn’t, it holds 60 psi on a compressor test).

On first inflation it will hold pressure for about 24 hours then goes flat, after that if you try and re inflate, the air comes out as fast as you can push it in.

Doing the soapy water bubble test, all the air is coming out from the valve hole and not the spokes, so I’m confident that I have the rim air tight (and the rear is holding well).

Short of putting a bed of silicone sealant around the valve base for it to seal against, I’m out of ideas, so any new ones would be greatly appreciated.

Any leak from the tape will appear to come from the valve. I find that increasing the amount of tape overlap helps. The tape doesn’t stick to itself as well as it doee to the rim.

Have you got the little knurled ring done up tight? I put my bodyweight on a cold chisel or a garden trowel pushing into the tyre side of the valve, compressing the sealing rubber and pushing more of the valve stem out of the rim so you can do the knurled ring up tighter. Still only tightened with fingers, though.

I cut the tape away around the edge of the valve hole so the rubber on the valve is pressed against the rim itself (and then the tape when it’s compressed) – seems to give a better seal, ime.

Tape needs to be really cleanly cut around the hole.

Tape needs to be really cleanly cut around the hole.

+1 I’ve messed up 1 or 2 in the past, a sharp knife and a keyhole file does seem to be the best way to do it. In contrast to Ned I start with the knurled ring only tightened up snug then tighten more if it’s leaking.

Gorilla tape and cut an X for the hole.

@ nedrapier, Yes, first thing I made sure of when I heard sssssssss

@ richardthird, exactly what I did on the other 4 wheels without issue.

Also made sure none of the cuts (and no tears) went past the hole rim.

I use a stitch cutter blade to trim the tape, use a mixture of Specialized and Stans valves. Never had one leak

You could try some PTFE tape around the valve

@ Steven, Alredy did that, its reduced the speed at which the air came out but didn’t cure it.

Just done this with a new set of enudro tech wheels. Cleaned the rims even though they new. Two wraps of 25mm gorilla tape then a tiny little hole made by knife then I ‘threaded’ the valve in through the tape.

Used the chainreaction own brand valves which usefully have a rubber o ring underneath the knurled ring so gives a good seal to the rim.

Used the new stans race sealant and hans damp / magic mary tires – pumped up to 50psi to sit tyre and not reduced in pressure over the last 4 days.

Sounds like you’ve got a leak in the gorilla tape?

@ Tracey, I’ve got similar, I have a Swann Moreton 11 scalpel blade which has a rounded cutting tip.

@ buenfoxa, I hope not, its triple wrapped over the valve hole! A very short piece went on first, just to act as a spreader and seal the 4 little holes the rims have there. Then the main wrap, starting 4 spokes past the hole, then finishing 4 holes the other way.

If you’re taping a wheel that needs multiple wraps, try putting a single layer on the whole wheel first to seal it. For additional layers only tape to either side of the valve. Then the valve is only trying to seal through one layer of tape.

I have a box of them, 100, from 1983 when I started windsurfing. They get used for a multitude of things.

I had a similar issue. Turns out the holes were schraeder, yet stans valves were presta. therefore a slight move of the valve caused air to leak. I discovered these reducers and everything’s fine now.

I had the exact same problem as you with some Hope Tech Enduro wheels. Turns out the valve and valve hole was fine – its the tape not sealing properly on the rim.

What tape youn using? Get some gorilla tape if not using already.

Secondly I had to roughen up the inside of my rims slightly in order to get the tape to stick better. After I did this it was perfect.

Did you pull the tape tight as you were applying it?

Scotroutes is spot on, a “leak” at the valve hole can be coming from anywhere in the rim, the valve hole is just the easiest exit for air- spokes seal their spoke holes up pretty well

People make cutting the valve hole really complex for themselves sometimes, I just get it stuck down then run a scalpel blade around the edge of the hole, can’t fail to get a perfect cut (as long as the tape is stuck down!)

Before taping, if it’s an old rim clean with isoproyl and let it thoroughly dry, you want it spotless. If it’s a new metal rim, scotchbrite/brillo pad it to give the tape something to key to.

Best valve imo is the superstar/WTB style one with the big conical bung, any valve’ll seal if everything’s perfect but these work even if things are all pretty iffy.

buenfoxa – Member

Used the chainreaction own brand valves which usefully have a rubber o ring underneath the knurled ring so gives a good seal to the rim.

Should never make any difference, the rim itself shouldn’t be pressurised.

Same problem here, but just on one wheel out of 4 (All Hope Enduro) – all done the same way and its’ driving me nuts!

Lots of PTFE tape with trial and error worked for me. I used about 5 wraps around the rubber base of the stem, tested, another 5 wraps, tested, another 5 wraps, etc, until it sealed and was holding pressure overnight.
It’s since done over 100 miles and is still sealed tight.

Edit – This was on a valve that I cut from an old tube 🙂

I heat up an old screwdriver and then pierce the valve hole using the hot screwdriver point.

Never had a problem I believe it seals the tape with the temperature.
Cutting a hole would tend to leave any layers open to leakage.

This can be a colossal PITA having gone tubeless innumerable times in the past, myself. There’s not much worse than the dreaded *ffsssshhh!* as the seal between valve and tape gives way.

I’m not a fan of Presta valves, so I’ve run Schraeder valves which won’t seat properly on some rim designs. Grabbing a set of pliers to tighten the lockring to Bastard Tight usually resolves the issue.

With Presta valves, you can inadvertently pull the entire valve free of the valve bed…

+1 for cutting a small X in the tape though.

[stealth edit] Sometimes, if the tape hasn’t seated correctly or has been pierced by an errant spoke then you’ll notice that pressure and sealant escapes into the inside of the rim.

I had a similar issue, where air leaked out over 24 hours, but read somewhere online to cut a small piece of old tube and put a pin prick in it and push the valve though…and it actually worked. It hasnt deflated since.

amazing how many “best” methods there are!

My latest bodge-a-rama was on a set of Stans Alpha rims that have always been a pig to get tyres to seat on. Eff loads of soapy water and uncomfortably high pressures. Always gone tubed before, swapped tyres round too may times to want to bother with faff of syringing up latex and rolling up spaffy tyres.

Race Kings went up OK tubeless, but still needed 60psi to seat, and popped back off the bead at 25psi.

all stans tape off and in the bin, trimmed stans tape on, only on the rim well, none on the bead shelf,. Pulled tight all the way around. Aired up high and left for the day. let down, tyre off, well was too dished to hold tape stuck down.

Stans off, trimmed leccy tape on, half width (9mm?) Stans round the centre to stop the leccy tape bulging into the spoke holes. .

Didn’t bather leaving over night. Went up straight away, stayed up, still up. Front tyre was wrong way round. Forehead slapped, tyre off, back on right way, back up and off.

Had to sew up a sidewall flapper on the rear tyre too.

Aren’t bikes fun!?

@ stevenk4563, yes, even used a hair dryer to make it more malleable confirming it to the rim.

Just bought more valves, more sealant, and some DT Swiss tape (got another wheel in the shop being built right now so were needed anyway).

IF I can face it tonight, I’ll pull the wheel apart, check all the tape (clear Gorilla) and take it from there.

buenfoxa – Member
Used the chainreaction own brand valves which usefully have a rubber o ring underneath the knurled ring so gives a good seal to the rim.

Should never make any difference, the rim itself shouldn’t be pressurised.

True but it helps to stop air escaping if there is a slight issue with air getting in to the rim. Likewise it helps to ensure a full seal for the valve itself.

Well upon closer inspection, the rubber surround of the valve was damaged. I’ve now set the wheel up, and it’s still leaking from a spoke hole it appears. I can hear it fizzing from here a good 8 feet away.

I’ll give it one more attempt tomorrow after that, the lbs can sodding well do it!!

I’m not a fan of the Stan’s valves. Much prefer the ‘free’ ones that come with dt’s wheels that have more stability as they seat to the rim bed as well, not just the Stan’s ones at the edge of the valve hole.
They are presumably available from other sources than DT.

I’ve solved a presta valve shrader hole problem by cutting a couple of washers from an old inner tube before.