I've found the exact one I have now - the previous link was the only link I could think at the time to give an idea. Been to the shed and checked out what it is...

http://www.evanscycles.com/products/...ector-ec007780

This is the exact one I use on MTB, wheelbarrows and the bike! It still has a screw fixing to the valve, but it has an internal valve so when you fit it the air won't escape, which would solve your problem I think?? Go and have a look in your local cycle shop they'll have something similar.

__________________