Faulty valve or operator error?

[lulubel]

I asked something along these lines on another forum, and was told you don't get faulty inner tubes, so I suspect this may be operator error!

My rear tyre has gone soft a couple of times while the bike's sat in the garage. It's fine if I pump the tyre up hard and take it for a ride. I think it has something to do with the removable valve core because both times when it's been soft, I've taken the dust cap off, and the valve core has come out with it. Both times, I've screwed it back in as hard as I can, pumped the tyre up, and put the dust cap back on gently.

Is this likely to be a fault with the valve, or me not screwing the valve core in tight enough? Would it be OK to grip it with a pair of pliers to do it tighter?

Tubes are so expensive, and we've had so many too badly damaged to repair lately, it's getting rather frustrating.

 

[Angelfishsolo]

If the valve core is coming off with the dust cap it is almost certainly a faulty valve.

Is this the type of valve you are using?



Woods Valve
A type of valve very rarely seen in the U.S., which has a bottom similar to a Schrader and necks down to about the size of a Presta is the Woods valve, also known as the "Dunlop" valve. Woods valves were formerly popular in the British Isles and Asia. You can pump them up with a Presta pump.

Woods valve

Older versions work with rubber tubing and spit. If they don't hold air, you can unscrew the knurled ring that holds the valve core (the "Presta-sized" part) in place. You should see a short length of rubber tubing covering the inner part of the core. If the rubber tubing has deteriorated,, the valve won't work. Some patch kits include short lengths of replacement rubber tubing for this purpose. When installing new tubing, lubricate the valve core with spit before slipping the tubing in place. Newer versions use a modern spring-loaded valve mechanism.

I asked something along these lines on another forum, and was told you don't get faulty inner tubes, so I suspect this may be operator error!

My rear tyre has gone soft a couple of times while the bike's sat in the garage. It's fine if I pump the tyre up hard and take it for a ride. I think it has something to do with the removable valve core because both times when it's been soft, I've taken the dust cap off, and the valve core has come out with it. Both times, I've screwed it back in as hard as I can, pumped the tyre up, and put the dust cap back on gently.

Is this likely to be a fault with the valve, or me not screwing the valve core in tight enough? Would it be OK to grip it with a pair of pliers to do it tighter?

Tubes are so expensive, and we've had so many too badly damaged to repair lately, it's getting rather frustrating.

 

[mickle]

If you have Woods valves I'd suggest you replace the tubes for some with Schrader valves. They're much easier to live with.

 

[tyred]

It must be a presta with removable core (I've never seen one but they do exist).

A shrader valve should never come out along with the dust cap unless the threads were completely knackered and that is most unlikely.

A woods valve shouldn't either. There would be a small possibility if it's a genuinely vintage bike with original tubes and metal dust caps which can screw tight enough to the retainer ring to lock together (can also happen with some pump nozzles) but the modern plastic dust caps aren't strong enough for this to happen.

 

[lulubel]

Sorry, I'm so dozey sometimes. The other forum I use is a specific roadie forum, so it didn't occur to me that no-one here would magically *know* I'm talking about skinny tyres and presta valves. (I prefer asking questions here because everyone seems friendly so far, and you don't get looked down on for asking silly questions.)

These are the tubes I'm using at the moment (700x18-25 Race 28):
Inner Tubes

The valves have a wide section at the base with a screw thread and a ring to tighten them against the wheel. The valve core screws into that, and the little loose bit that you have to release and push down to open the valve is inside the core. (I hope that makes sense.) The dust cap screws onto the core, not the outer casing of the valve.

Twice, when I've removed the dust cap, it has unscrewed the core with it, and let all the air out of the tyre, which is why I'm assuming the core isn't going in tight enough. Since the first time it happened, I'm being careful not to screw the dust cap on too tight - just far enough not to work its way loose on the bumpy roads.

I've used Conti tubes ever since I've had the bike, but I haven't come across any that have done this before. I hadn't even heard of removable valve cores until I came across one that was falling out on this latest batch, so I don't know if the older ones have been the same.

 

[HLaB]

Ah what you are calling the core isn't what I'd call the core but the valve and the little bit inside I refer to as the core. The outer bit is just the lockring and tbh I remove them. If air is coming out its unlikely to be the valve unless damaged (where it meets the tube is common with Spesh tubes). I'm maybe teaching you to suck eggs but are you remembering to tighten the bit inside the valve (the bit that you push down to open the valve). PS I've used plenty of conti tubes and never had a problem with them other than their yellow cap doesn't look good IMO ;-)

 

[stevevw]

I have had a couple of tubes where the same has happened. Just screw it back in untill it seats snugly not over tight and all will be well.

PS I like the yellow caps

 

[lulubel]

They used to have blue caps, which I prefered because they matched my bike.

Yes, I do remember to tighten the little screw bit - I thought at first that I hadn't tightened it properly when the tyre was soft, and the next time did it so tight that I had trouble undoing it again! It did take me some time to figure it out when I first got the bike, though.

I've found an old wrecked tube with the same kind of valve hanging around in the garage, and the inside bit/core/whatever, is so tight in that one that I can't unscrew it, so it might be my little girly fingers aren't tough enough to screw it in properly! I'll try wearing a washing up glove later. That might give me better grip.

 

[Fiona N]

These are the tubes I'm using at the moment (700x18-25 Race 28):
Inner Tubes

I feel your pain

I know exactly the tubes you're talking about - Michelin A2 I think they're called - you need to get the A1 without the removable valve. No idea why these completely stupid inner tubes with removable valves are sold but they're a nightmare. Recently I used one to replace a punctured tube on an Audax and had to keep pumping it up every few miles as the valve wouldn't seal. In the end I gave up and changed to another tube. The thing is you don't know you've got them until you unscrew the valve. I Super-glued the valve in on the two new tubes I have and that seems to have done the trick but it's either that or chuck them.

 

[zacklaws]

I have had this problem, and thanks to Svendo on this forum, he told me how to solve the problem.

Unscrew the valve and apply some thread lock and screw it back in tight with a pair of pliers.

When you pump the tyre up, turn the wheel till the valve is at the 12 o/clock position, get a small container of water and immerse the valve completley and look for a tiny stream of bubbles either coming from where the valve screws in, or where the little screw cap at the top tightens it up. applying spit to the valve does not work as the bubbles are too microspopic if it is a small leak. Adding washing up liquid to the water helps as it then makes bubbles form on top of the water.

If you see bubbles coming from the end of the valve, then the cap might not be tight enough, if it comes from the side of the valve where it screws in, then it needs tightening a bit more.

It is frustrating to unscrew the valve and part company with it as it blows out of your hand

 

[GrasB]

Almost all my 'tubes have removable cores & I've had very few problems with them, that said I do have a valve core spanner (you can see a cheap one in the valve extension pack pictured below). Those I have had problems with have been consistently bad even when using valve extensions so presume that there's a problem with the tube.

No idea why these completely stupid inner tubes with removable valves are sold but they're a nightmare.

+
so much better than valve extenders where you can't properly seal the valve shut (you're forever pumping the tyres up).

 

[Davidc]

I've had exactly what you're talking about, particularly with some conti tubes I bought last year. I did what Zacklaws says above in post #10 but used nail varnish as thread lock. An extra 1/4 turn using pliers after it was too tight for fingers as well.

I have occasionally had a problem with both presta and schraeder valves with dust getting in and allowing very slow air loss. Blowing the tyre up to maximum and then letting the air out as fast as possible usually cures that.

 

[Cubist]

Yep, good old Conti tubes. Threadlock and tighten them with a pair of pliers.

 

[Tim Hall]

I put a turn of PTFE tape on the thread, then tighten it with pliers.

 

[lulubel]

Thanks for the suggestions. I'm glad it isn't just me being totally incompetent.

I've tightened it up a bit more now - got more grip wearing rubber gloves and couldn't unscrew it afterwards with just my fingers, so definitely tighter. That should be OK for my ride tomorrow morning, even if I have to put some more air in the tyre just before I leave. I know it's fine for 20 miles or so.

Then I can take it out and try and sort it after I get back. Is the tape the stuff that plumbers use to seal joins in pipes? I think we've got some of that. Failing that, I've got nail varnish.