Presta Valve Cap

[deus44]

Hello,

I am working on a project and need to reproduce the threads on a presta valve cap. All my research online seems to indicate that they are non standard threads. I found a thread on this site that talks about it in a little detail but not much. There was mention of the Tire and Rime Association handbook that might have the details of this thread, but I do not have access to one. I am hoping that someone on here might be able to give me the details.

I am producing these threads in a CAD model so the pitch and cut depth of the threads would be ideal, but any information would be useful in replicating the thread.

Thanks in advance

 

[ACtrafficengr]

Have you tried the Bicycle Engineering forum in this website?

 

[CapriRacer]

There was a similar question asked sometime back. Ah, here it is:

Link

And here is a link to an image of the pertinent Tire and Rim page listed in this thread:

Link

 

[CapriRacer]

And at the time, I said to do a reality check. Don't accept that what Tire and Rim says is what was done. Check before you cut.

 

[deus44]

Thanks for all the responses. I've looked through the bicycle forums and there is nothing there on the threads. Also that image that was linked to, I have looked at. It was actually how I found this site. While it does give informaion the diameter of the threads it says nothing about the pitch or the dpth of the thread. Its probably on the next page.

 

[CapriRacer]

On the image, I see a note to the right that says: 5VI(.210-36 THD.)

Is that the thread you are talking about? As far as "depth" is concerned: Aren't screw threads standardized so if you know the pitch, it also defines the entire shape of the thread?

 

[deus44]

I see what your talking about. That thread is where the locknut screws down o hold the valve stem in place and doesn't rub on the rim. I am interested in the three or so threads at the top where the plastic valve cap screws onto. On the image I believe it would be around the E diameter, though based on my measurements E would be the minimum.

 

[CapriRacer]

OK, Now I see the problem. You're looking at this backwards. Everything you see in the drawing is a hole, not the outside of a tube. The thread I pointed out is internal, not external. The valve screws into that and the valve seats against the taper located where D Diameter is delineated.

Therefore the E diameter is smooth - not threaded.

If I am reading you correctly, you are looking for the thread size for the cap that fits over the end of the valve - right? That's not depicted in that drawing as that drawing is only showing the details for the valve itself.

The drawings for the valve cap are on a different page - and rather than go through all the work to post the page, it turns out there are only 2 different valve cap threads - 8V1 (.307-32THD) and 12V1 (.485-26 THD)