simple question , hard to find clear answer

[ditdater]

a bike or car regular valve stem cap size ?. I bought a project 346 s shifter for my rat fink 3 sp. . I can perfectly screw on a reg. valve stem cap on the shifter after I unscrew the small round knob it came with. I/m looking at twisted shifterz website for a cool replacement knob , but they need the size ,as most of theirs are car gear shifter size . anybody know exact size to ask for ?
thanks, danny 502 432 3684

 

[sensor]

You need to know the thread pitch and size of the shifter you have and then you can get the info you need to tell the place that makes the knobs. Until that, or someone with the 346 shifter posts it, its kinda impossible to answer. It would, more than likely, be metric since the shifter was made over seas.
You can get a thread pitch gauge really cheap(again I'd say metric) and then just measure the threaded part of the shifter(again metric) for the width.
Can't help anymore than that other than go to a hardware store, take the shifter, and try threading random nuts on until you find one that works. Then you will have the size/pitch for it to tell the knob maker.
Hope that helps.

 

[clamdigger]

From Sheldon Brown's Bicycle Glossary " the external threaded part of a schrader valve is 7.7mm ( .3o2" ) x 32 TPI

 

[deorman]

Hardware store sizing gauge + valve stem = answer.

 

[Bicycle808]

From Sheldon Brown's Bicycle Glossary " the external threaded part of a schrader valve is 7.7mm ( .3o2" ) x 32 TPI

As usual, Sheldon Browns was right. (And Kenny was right to quote him.) A quick googling of "Schrader valve thread" suggests, time and time again, that it is indeed 7.7mm x 32tpi. Here are some in-depth specs from a home machinist forum post.
http://bbs.homeshopmachinist.net/threads/32634-Schrader-Valve-thread