You must take both diameter and pitch into consideration. All three pre-ISO thread standards are separated by only .3mm (.012") so unless you have an extremely accurate micrometer, and threads in good condition, diameter alone is not a reliable way to distinguish them.
This is especially true with French and English, as they are only .1mm (.004") different diameter. English and Italian are .2mm (.008") different, and are both 24 tpi, which is why the groove. French thread is 1mm pitch (25.4 tpi), so it can easily be identified using a pitch gauge.
So it looks like you have one French and one English hub.
Greg Reiche CyclArt Vista, CA USA
-----Original Message----- From: firstname.lastname@example.org [mailto:email@example.com]On Behalf Of bruce thomson Sent: Friday, December 05, 2008 2:04 PM To: Classicrendezvous@bikelist.org; firstname.lastname@example.org Cc: email@example.com Subject: Re: [CR]Information Please: Campagnolo High Flange thread pitchgrooves
John: Please don't misinterpret this as an ungrateful reply. I am not completely satisfied with your answer, (no its not you), but I think you a nswer is incomplete. I believe you when you say that the thickness or ou tside diameter of the the threads is distinguishable but when I measure two of my rear hubs, both are 35mm, including the one with the "groove". Th erefore, I have two hubs with the same thread OD and differing thread pitch es, I know I saw this information somewhere at an earlier time.
Bruce Thomson Spokane WA 99204 (509) 747 4314 Masi3v4me@yahoo.com firstname.lastname@example.org
John Thompson wrote:
> bruce thomson wrote:
>> My small flange hubs have the thread pitch stamped between the end of the f
>> reewheel threads and the flanges. My High Flange hubs do not. But on some there are grooves. No groove meand ??, one groove means??, and two gr ooves mean ?? I saw this information at least one time earlier and now cannot f ind it. If anyone has the answers AND a source please reply.
> Your large flange hubs are older than your small flange ones; Campy only started printing the thread pitch in the early 80's IIRC. A single groove o n an older Campy hub indicates English threading. 2 grooves is French, no gro oves is Italian.
Whoops! My mistake; Campy only marked English threading; French and Italian are unmarked but readily distinguished by the 1mm difference in diameter (35mm=French, 36mm=Italian). An Italian freewheel will not engage a Fre nch thread hub at all, and a French freewheel is to small to even start on an Italian thread hub.
-John Thompson (email@example.com)
Appleton WI USA