Originally Posted by Witterings

I did have another thread running on this as well to see if I could find what the problem was ... some of the chucks on the end of the inflator aren't great and were struggling to get a proper seal so you couldn't get an accurate pressure reading which I think was caused as the pin in the presta popped back out with the pressure from the air in the tyre ... it was also a lot worse on one tyre than the other where they had slightly different valves .. one had no thread / retainer and is the one that caused the worse issue.