sreten

Hi,

You need to keep tightening the outside valve retaining ring once
the tyre is properly seated (*) and have a good idea how much it
should stick out when it is properly seated on the rim.

rgds, sreten.

* The rubber valve seat can also get stuck under tyres in narrow
rims preventing proper tyre seating causing a bulge at the valve.
Usually on one side only and that I'd assume can cause the
same sort of tear in the innertube, I only noticed fitting my
tyres because the reflective rings made it much more obvious.