Help: Valve extenders Shimano

[stratus5]

Hi

I have a set of Shimano valve extenders for a presta type valve, which came with small rubber O-rings.

 

If I screw the extenders without the o-rings they leak which makes it difficult to gauge the tyre pressure.

 

I have seen plumbers tape recommended for the seal, which could fix the problem, but where the heck are the o-rings supposed to go exactly? I have tried various combinations, but with no joy.

 

Once the tire is inflated, do you leave the extenders on, or unscrew them?  If you get a puncture on the road, the tube has to come out anyway.

 

They can always be screwed on again when you need to inflate the tyre again every few days ... I think.

 

The brass extenders seem a bit heavy to leave in when you have spent all that money on lighter rims.

 

Thanks

Craig

 

[droo]

Seat the o-ring on the valve stem, just past the thread for the valve cap, then screw on the extender.