Tractor tyre valve thread

[Mike Richards]

Trying to find out what the thread is on the outside edge of a tractor tyre air valve. Want to make a pipe to screw into this thread to get air into tyres faster when seating them on the bead. Thanks in advance.

 

[milkloss]

Trying to find out what the thread is on the outside edge of a tractor tyre air valve. Want to make a pipe to screw into this thread to get air into tyres faster when seating them on the bead. Thanks in advance.

I can’t remember other than they are the same as an earthmover valve fitting. Don’t buy a quick release fitting for one as I did because the thread on a tractor isn’t long enough to fit.

 

[Mike Richards]

I’ve got one pipe made up now which is a 1/2 whip hose that’s had the end tapped out to fit nicely over the outside of the valve stem once the actual valve has been removed. I inherited the pipe of of someone who can’t remember who tapped it out. Looking for a spare just in case I loose this one out on a callout.

 

[milkloss]

Here you go. I think it is a vg12 but have a measure up first.
https://www.ring-plug-thread-gages.com/PDChart/Tire-Valve-thread-data.html

 

[Mike Richards]

Thank you very much. I know it’s 26 tpi but couldn’t find the thread type.

 

[tinman]

iirc i looked for a tap to do the inside thread and a die for the outside thread before and to buy one was mental money, unless im mistaken i think they can only be sourced form the states too and i think wild hard to find.
but that must be a yr or two ago now so i might be wrong.

a 1/4 bsp female airline adapter will screw on good enough, not the same thread but will hold and do no damage, of course im not implying you should do that as it would be dangerous if forgot about.
best if you could get a hose to push onto it, least if it put too much air into the tyre it would blow off before doing harm.

 

[Treemover]

A good few tyre places just use a hose with a jubilee clip. They dont even tighten the jubilee clip each time. Once its snug enough; its set.

 

[farmerste]

A good few tyre places just use a hose with a jubilee clip. They dont even tighten the jubilee clip each time. Once its snug enough; its set.

thats what ive always used,works really well

 

[sjt01]

Thank you very much. I know it’s 26 tpi but couldn’t find the thread type.

26 tpi sounds horribly like British Standard Cycle thread. Apologies that the table pastes in upside down! Copied from https://britishfasteners.com/threads/bsc.html

BSC (British Standard Cycle) Thread Data
This fine thread profile was formulated for, and is well suited to cycle and motorcycle applications. Its fine pitch, allows high torque settings, and resists the tendancy to loosen under vibration, the larger core diameter also gives greater shear strength. Most people think that all cycle threads are 26 tpi pitch. Whilst this is true of all the most popular sizes from 1/4" to 3/4" diameter, other pitches were also used as shown in the tables seen in the CEI section

1 inch	26 Tpi	0.0385	0.959 ins	0.9688 (31/32) inch 24.61.1 mm
0.6875 (11/16) inch	26 Tpi	0.0385	0.6465 ins	0.6496 inch 16.5 mm
0.625 (5/8) inch	26 Tpi	0.0385	0.5840 ins	0.5906 inch 15 mm
0.5625 (9/16) inch	26 Tpi	0.0385	0.5215 ins	0.5156 (33/64) inch 13.1 mm
0.5 (1/2) inch	26 Tpi	0.0385	0.4590 ins	0.4606 inch 11.7 mm
0.4375 (7/16) inch	26 Tpi	0.0385	0.3965 ins	Letter Drill X 0.3976 inch 10.1 mm
0.375 (3/8) inch	26 Tpi	0.0385	0.334 ins	Letter Drill R 0.3368 inch 8.65 mm
0.3125 (5/16) inch	26 Tpi	0.0385	0.2715 ins	Letter Drill J 0.2756 inch 7 mm
0.281 (9/32) inch	26 Tpi	0.0385	0.2403 ins	Letter Drill D 0.2441 inch 6.2 mm
0.250 (1/4) inch	26 Tpi	0.0385	0.2091 ins	Number Drill 3 0.2188 inch 5.56mm
0.1875 (3/16) inch	32 Tpi	0.0312	0.1542 ins	Number Drill 23 0.1562 inch 3.97mm
0.1563 5/32 inch	32 Tpi	0.0312	0.1231 ins	Number Drill 30 0.126 inch 3.25mm
0.125 (1/8th) inch	40 Tpi	0.025	0.0984 ins	Number Drill 39 0.1004 inch 2.5mm
Diameter (Inches)	Threads per inch	Pitch (Inch)	Core Diameter (Inch)	Tapping Drill Size