'72 Campagnolo Hi-Flange Record Hubs, which thread?
 

Hi,

ages ago i bought some used high flange record hubs on ebay. Contrary to other Campy hubs i have, the freewheel size is not marked with anything obvious. After taking them apart i saw the date code on the cones was '72. They've been sitting for a while waiting for a suitable project. Now they are laced and ready to go, but one question remains. Which thread? I'd think the answer would be obvious, but in going through my stash of freewheels, i notice that all kinds seem to fit. I tried a french thread Maillard 5 speed and it rolls on fine. A Regina Gran Sport (not sure which thread is on this one, but Velobase says they were only available in English and Italian) also fits. I could keep trying others, but i wanted to ask around if there is a pretty easy way to detemrine the thread. I don't have digital calipers.

I had the idea to try some bottom bracket lockrings. ITAL was too big and just slid on, but BSA and FRENCH threaded on fine. Any tips?

oh and before i forget, i check the forum already and found this post which seems to confuse me even more, seeing it says French shouldn't be interchanged with anything.

Thanks in advance,
Dan

The only way I know to check for sure is to measure the threads. If you have a steady hand and a good ruler you can count the number of threads in the threaded area and compute threads per inch or thread pitch. English are 24 threads per inch. The Italian is I think very close to that, and I know the French is different. If you have a caliper that reads in thousands of an inch, measure the diameter of the threaded area. English will be 1.3750 inches, Italian will be 36.0 millimeters (divide by 25.4 exactly to convert to inches). I may not be right, but I think French has a 35 millimeter diameter.

Don't thread that lockring over it any more. The threads on the hub are delicate and not restorable if distorted. Kill the threads, kiss off the hub body, hunt on Ebay for another one.

Campy supplied hubs in whatever threading the bike company required. The only thing age or production year (not necessarily 1972, btw) had to do with it is in some years it was hard to see what thread you have.

If you take this from the link provided:

English: 1.370" x 24 TPI (34.80mm x 1.058mm)
French: 34.7mm x 1mm (1.366" x 25.4 TPI)
Italian: 35mm x 24 TPI (1.378" x 1.058mm)

And rearrange the numbers you'll see that all 3 are very close:

35.0 X 1.058.Itlalian
34.8 X 1.058.English/BSA
34.7 X 1.... ..French

Obviously Italian, being the largest diameter will be most likely to slip on/off of an English hub.

Check your hub closely, I think you'll find it is marked with a thin groove on the shell. Look on the shell between the back of the threads and just before the flange.

Jim

thanks. what could this imply for interchangeability? sutherlands handbook says that french won't work because the thread pitch is too different, even though the diamater looks pretty close. anyone ever try this?

even though i am not quite sure what i should be looking for, i checked the hub again and didn't see any groove. pic attached. refering to sutherlands again it states:

English 1 groove
French no groove
Ital no groove

this suggests a french or italian threaded hub. i'll see if i have any known italian freewheels to try. but i am guessing french, since the french freewheel spins on pretty well.

Do yourself a favor. And you can go pretty cheaply on this. I have a 4" and 6" set of digital calipers from Harbor Freight, neither of which I paid over $10 for on sale, and a set of metric and standard thread pitch gauges that came with an inexpensive tap/die set. I've spent money on things I don't use. Not these. They are very handy.

I'll bet it's english.

Honestly, in nearly 35 years of messing with this stuff I've only run into ONE French freewheel and one set of hubs.

Reads like a French Hub that has been forced to accept an english freewheel, pretty common in the USA as hardly anyone knew about French freewheels. That is why both spin on reasonably well.

I'd put money on Italian. If it were english there would be a groove just inboard of the threaded portion and it would be obvious, you would not have to look closely.

Did campy even do french threaded hubs?

It implies that a slightly smaller diamter French freehwel may be used a British threaded hub. If the French freewheel is slightly oversized and the hub slightly undersized it could thread on all the way. Sometimes it takes a little working and back and forth with well lubed threads. On the other hand if you have slightly oversized British freewheel with a slightly undersized French hub the freewheel may not even thread tightly which results in stripped threads.

And yes, I've tried it. Its not recommended.


Pic of 'groove':

http://i495.photobucket.com/albums/r...7/DSC02468.jpg

According to the '82 Olympic catalog the answer is 'yes'.

well, i did in fact buy these hubs from ebay france. but that doesn't say anything really. as we all know, parts of all types are spread all over the world. i'll try and check the diameter and try out some other options. thanks for all the replies!

here's an update. i remembered i had some track cogs, shimano (ISO) and French. I tried both of these and what do you know, the french threads on all the way. the shimano cog threads on the hub 3/4 down and then jams. of course i sense that i could force it, but i luckily i have enough spare sparts in both threadings that i don't need to.

so i've actually done a good deal of research on this topic and found some useful links. in case anybody needs some help they are:

here and here

i am still wondering, can pitch really be the limiting factor? is the danger in cross-threading the hub? honestly i am bit stumped as to why someone would recommend using say, a italian freewheel (largest diameter) on an ISO/ British hub. to me it seems the .2mm difference in diameter would be a bigger deal. i'd expect this combo to have some play. i mean going the other way is kind of fathomable, so it is possible to fit a british freewheel to an italian hub. but even here, i'd expect the freewheel to shave off some of the threads leaving less material to engage. also potentially a problem.

Pitch is the bigger issue! With the wrong pitch, all the stress is put on one or two threads, which can shear in a progressive spiral around the threaded snout of the hub.

French freewheels are the least likely to fit anything else, and go most of the way on then grab.
English and Italian usually will spin fully on to a French-thread hub.

The best way to check threads is to use a normal, Shimano or Joytech, 1mm-pitch, 9 or 10mm axle (i.e. not Campagnolo, which is 26tpi). This threading can be seen to mesh fully with A FRENCH hub's 1mm-pitch threads if you hold it up to a light background or window.
Conversely, an English-threaded (1.37X24TPI) bottom-bracket adjustable cup will mesh perfectly with English or Italian hub threads, but not French.

There you go. No guages. Micrometers and calipers should not be trusted too much.
The diameters are somewhat variable in practice while the theoretical differences are comparatively miniscule.

Anything bought from France that's before 1980 or so is almost certainly French-threaded. Sellers usually don't like to reveal this fact!