Originally Posted by ZappCatt
There are 3 standards for threads...As you can see they are very similar. I know(because I have done it) that you can go from Italian(Miche) to English(DuraAce) with no trouble. Once you decide which standard you want to follow, you should probably stay with it..since there will be some deformation of the threads if you jump back and forth.
English 1.37" x 24tpi (current standard),
French 34.7mm x 1mm,
Italian 35mm x 24tpi
For lockrings there are the 2 major standards
ISO/English standard size 1.29" x 24 TPI fits most U.S., English, and Asian fixed gear hubs.
Campy/Itailian are used on Phil Wood hubs, and most Italian-made(Miche) or French-made hubs.
There seems to be a bit of question in this thread about lockring vs. cog threadings. On the track, unless you go back before the 1960's, there are basically two COG threadings: ISO and BSC. The threads measure out virtually identical, but they are still slightly different and (and this is where it gets important) the ISO threads are not cut as deep as BSC. As a result, you can get an ISO threaded cog onto a BSC threaded hub, but you polish off the tops of the threads and also shave the sides just a bit. Ultimately you increase the risk of stripping your hub threads.
Hub damage can also occur from some of the hard coating used on certain cogs, Suntour Superbe Pro's in particular. You need to use a wire brush or a scribe to clean out the threadings on those hubs. There's a bunch of powdery junk that comes out that otherwise grinds down your hub threads. EAI cogs don't have this problem, nor do Phil Woods.
The other threading issue is at the lockring. There are three versions: BSC (used by Shimano, Suzue, Suntour, and most of the rest of the world), Campy (used by Campy and the Campy clones such as Gipiemme, Zeus, etc.), and Mavic (used, predictably, only by Mavic). They are not interchangeable. A BSC lockring will fit with difficulty on Mavic threads, but again it will damage the threads.
In picking cogs one other dimension to worry about is the depth of the cog and the depth of the hub cog threading. Some combinations give sufficient room for a lockring to thread on properly, in others the cog sticks out and only allows a thread or two worth of grip for the lockring, and in a few the cog needs a spacer between it and the lockring or the lockring will bottom out before it hits the cog.