Deflating problem

[pixiepie]

Hi everyone,

I'm just after a bit of advice about repairing my tyre... yesterday I discovered I had a flat. I've pulled the inner tube out and pumped it up. It looked fine and there was no sign of a puncture and it stayed inflated but my track pump wasn't registering any pressure even when it was fully/over inflated.

I let the inner tube down, re-inserted and then pumped it up again.

This time, the track pump still wasn't registering any pressure and it instantly started deflating (hissing quite loudly) from the valve.

I assume this means there's an issue with the valve and I need to replace the inner tube but has anyone got any idea why the valve only starting leaking when the tyre was on the rim?

Also, I have a bike with hub brakes and hub gears. Anyone got any hand hints for taking these off so I can get the wheel off or do you think I should get it to a bike shop and let the professionals have a look. I guess if there's a problem with the rim, it would make sense to have the pros looks at it anyway.

This is the bike, if that helps: http://www.edinburghbicycle.com/products/revolution-heritage-deluxe-13

I've had it around a year.

To give you an idea of my bike fixing skills, I can fix a puncture but that's about it! Anything more complicated and I'm lost.

 

[Cycleops]

Valves can fail although it is farly uncommon. Is it a a Schrader, Presta or a Woods?

I think you are saying you have a problem with the rim. Unless you are familiar with removing the wheel best take it to a bike shop and let them do it.

 

[pixiepie]

It's a Shrader. I only suspect it's rim related as it was fine when I inflated it when it was off the rim. It was only when I put it back on that it started deflating. Moving the valve around when the inner tube was on the rim seemed to have an effect on how much air was coming out as well. Maybe the rim is pressing on the valve? Dunno

 

[ufkacbln]

Sounds sad, but it isn't

Use the valve as a fixed point on the rim.

Always align a letter on the tyre with the valve

That way you will always be able to pinpoint where a puncture occurs

 

[pixiepie]

Sounds sad, but it isn't

Use the valve as a fixed point on the rim.

Always align a letter on the tyre with the valve

That way you will always be able to pinpoint where a puncture occurs

Is this meant to be specific advice that relates to my valve issue? If so, I can't see how it's relevant since I don't appear to actually have a puncture.

 

[marzjennings]

Sounds like the value has failed and can't hold any pressure, could be a small piece of dirt in the value or a small split at the base of the value which is hard to see. Chuck it and get a new one.

Take it in and get the shop to change the tube. If you call them and schedule a time they should be able to change the tube while you wait. Shouldn't take them more than 10mins to change the tube.

You're not going to register any real pressure on your pump when you inflate a tube on it's own. It only takes a few psi to cause a tube to balloon out.

 

[Cycleops]

Difficult to see how it can be rim related if the air is coming out of the valve. Schrader valves have a core you can remove, but I've never done it, might need a new one maybe just has dirt in there.

 

[pixiepie]

Sounds like the value has failed and can't hold any pressure, could be a small piece of dirt in the value or a small split at the base of the value which is hard to see. Chuck it and get a new one.

Take it in and get the shop to change the tube. If you call them and schedule a time they should be able to change the tube while you wait. Shouldn't take them more than 10mins to change the tube.

You're not going to register any real pressure on your pump when you inflate a tube on it's own. It only takes a few psi to cause a tube to balloon out.

OK, thanks. Yeah, it wasn't registering any psi when the tube was in the tyre either which I thought was odd. But as you say, it's probably because the valve has failed. I suspect there's an issue with the hole in the rim where the valve pushes through (it looked a bit rough) so I think I want the shop to look at that anyway before I waste any more inner tubes on it.

Thanks for the advice.

Just need to work out how to get it to the bike shop now!

 

[ufkacbln]

Is this meant to be specific advice that relates to my valve issue? If so, I can't see how it's relevant since I don't appear to actually have a puncture.

General.

 

[Cycleops]

Ah ha! If the the air is coming from the direction of the valve it may not be the valve, especially if you say the valve aperture in the rim looks rough. Could be this has caused a puncture at the base of where the valve is. Try smoothing area with a bit of sandpaper, or better a file.

 

[pixiepie]

Ah ha! If the the air is coming from the direction of the valve it may not be the valve, especially if you say the valve aperture in the rim looks rough. Could be this has caused a puncture at the base of where the valve is. Try smoothing area with a bit of sandpaper, or better a file.

The thing that's confusing me is that the inner tube stays inflated when the valve is not stuck through the rim in the whole. Surely if it was a puncture, it would lose air either way? The bike's at work so I'll have another play with it on Monday. I'll see if any of my work's "proper" cyclists can give me a hand!

 

[pixiepie]

Found it!

The puncture is actually on the valve itself just above the thread where the dust cap goes. Tried and failed to patch it - there's just no room - so it's going into the shop tomorrow. I've had it a year so it's probably due a bit of a once over anyway.

Thanks for all the advice.