Sorry if this is in the wrong place, I'm sure there should be a forum for this sort of thing but there's so many sub forums I just never spotted it.
I noticed the other day that my back tire was getting a bit flat so as you do I decided to pump it up. It all seemed to be going so well buit...I can't seem to pump up the tire and then have the air hold. The minute I disconnect the pump it all comes shooting out of the valve and I've no idea what to do at all.
This is my first time with this type of valve and I'm really unsure what the trick is.
I've made a video to demonstrate the problem:
Can anyone help?