Valve thread size

[mattsccm]

Anyone know what the threads are down the outside of a Presta valve? Can't find my thread gauge.
I am sure that a nut would be better when trying to get a tight turn for tubeless tyres.

[Braceby]

Metric fine, m6 x 0.75

[mattsccm]

Thanks

[Barrowman]

I had an issue with tube creep trashing tube at the valve on a machine and I utilised nuts (which came off some really old high pressure tubes ,they used to make them like that, the bottom of the valve sat in a pocket in the tube, an oval plate sat outside the tube and the nut made the airtight seal. ) Also made a rubber gasket made from an old tube slipped over the valve to go inside the rim and a soft washer
(copper/nylon can't fully recall )between the outer rim and the valve Nut. Can't help with the thread spec though, sorry.
I used the nuts in preference to the knurled ring which helped but I suspect tyre and rim were just a poor combination and the valve hole may have been nominally oversize .

[Jdsk]

Metric fine, m6 x 0.75

Wikipedia and a few other sources have have 6V1, 6 x 0.80 mm:
https://en.wikipedia.org/wiki/Presta_valve

I don't have copies of either ISO 4570 or 9413.

Please could someone measure the pitch with an appropriately precise instrument. Or find the relevant document.

Jonathan

[tenbikes]

You can buy ' nuts' specifically for tubeless valves which are chunky and easy to tighten by hand. I have them on my fat bike wheels .

[Barrowman]

Just searched 'Cycling Valve Nuts' on E Bay looks to be some custom ones at not huge cost.

[Brucey]

I think the standard nuts are almost invariably brass so modification via soft soldering (once the plating is removed from the relevant surfaces) ought to be very easy. If you fold up a kind of diamond shape in suitable wire, then solder this to a nut, you will have made a kind of lightweight wing nut, much more suitable for the task in hand. 'Suitable wire' could be copper, brass, or even a bent paperclip.
I also think it would be very easy to grind or file flats onto a knurled nut, so an 8mm spanner fits.Two flats ought to be plenty, because access is good.

[Brucey]

if anybody wants to know if the thread pitch is 0.8 mm or not, nothing could be easier; just hold a length of standard M5 (x0.8 mm) studding alongside,as a kind of ersatz thread pitch gauge.