since6

I have a six speed Shimano Dura Ace MF-7400 freewheel on my Campagnolo Nuovo Record hub and am looking to replace it with a larger 24,26,28T freewheel. How can I tell which six speed freewheel I should be looking for, english or italian? (I'm leaving out french as I doubt it would apply) When new the freewheel that was specified for this hub was a Suntour Ultra 6 freewheel. I've found, printed and begun reading Sheldon Brown's excellent discussion on freewheels, which I would highly recommend to those like me just starting into vintage. Thanks for your advice.

T-Mar

My 1985 Dura-Ace literature does not specify any threading option for the MF-7400 freewheel, unlike the bottom bracket and headset. Consequently, it appears to be English only. Since you have been using an English threaded threaded freewheel, I would replace it with another English/ISO threaded freewheel as, even if the hub is Italian threaded, switching to an Italian threaded freewheel will only cause further thread damage.

unworthy1

As Sheldon has explained, the difference between the threads (both hub and FW) between BR/ISO and ITA is so minor that it makes no difference IF you make the "B" grade mis-match as long as you stick with that mismatch once you have committed to it. The soft threads of the hub will be slightly deformed from the steel FW threads and you want to make the deformation one time only and then stick with it.
Your DA FW is undoubtedly ISO (as T-Mar says) and the Campy hub MAY have the threading indicated on the flange you'll see once the FW is off, but whether ISO (Campy like to use "English") or ITA the answer is stick with ISO FWs (which are FAR FAR more plentiful than ITA anyway)

Camplex

+1 T-Mar.

British/BSC ... I have the same FW.

79pmooney

I'll second what's been said above. English/Japanese is a force fit on Italian threads the first time. Once that is done, the match is fine. But going back to Italian is a no-no. You risk stripping the threads. (A real bummer on a ride. And a killer for a good wheel.) So enjoy having a huge variety of freewheels to pick from, just not Italian.

Ben

since6

As to matching that choice was made by the prior owner who installed the Shimano freewheel on the Campagnolo hub, however given that this bicycle was made with a Suntour Ultra 6 freewheel this was probably a prudent choice? Does anyone know if the Suntour Ultra 6 was an English freewheel? So, given your advice I will stick to English freewheels. So far I have been pleasantly surprised that there are a fair amount of Regina, Suntour and Shimano freewheels available, some even NOS, with a 24-28T upper range in six speed cassettes. Among the six speed freewheel manufacturers are there better/worse brands, and/or, models you would recommend?

79pmooney's post really makes me wonder, did Suntour make a set of Italian threaded Ultra 6 freewheels, or, did Campagnolo have Nuovo Record hubs that were English threaded rather than Italian, or, as 79pmooney suggests did the factory force thread the Suntour Ultra 6 freewheel onto the Campaganolo Nuovo Record hubs?

Thanks again for your advice.

dddd

I've never heard of threads getting stripped from changing between English and Italian threading. Sounds like theoretical speculation.

Even the case of vastly different French and English threading, different pitch AND diameter, some have used that combo on TANDEMS, and countless Peugeots are running around to this day with larger English-threaded freewheels installed on French-threaded hubs, with rather few failures to speak of.

When a thread failure does occur, it is because the thread pitch difference puts the force on just a couple of turns of threads, which then must deform in order to allow force-bearing contact with any greater number of threads. So one would not want to switch between French threading and English-Italian threading, particularly more than once, as the threads would see repeated cold-working and would thus be much more likely to fail.

Where very high torque loadings are likely, as with tandems, mtb's and very low gearing with heavier loads, consideration of threading issues becomes a significant concern when French threading is mixed with English or Italian threading.

Suntour freewheels were offered in British and "Metric" (French) threading, as marked on the outboard end of the inner hub. Shimano made only English-threaded freewheels. Neither was concerned about their use on Italian-threaded hubs.

JohnDThompson 

I agree that having used an English thread freewheel on the hub until now, you should replace it with another English thread freewheel to avoid re-working the hub threads again. But that said, you never specified the thread type on the hub. Campagnolo offered their hubs in Italian, English and metric (French) thread, and since around 1980 the thread type has been clearly marked on the hub shell just inboard of the threads. Prior to 1980 or so, the thread type was indicated by the presence or absence of a groove just inboard of the freewheel threads. Both French and Italian lack a groove, but the diameter of the threads is enough different that it is impossible to mistake them.


Source: Sutherland's 4th Edition

squirtdad

+1 if the hub is english the you are total match, if it is italian, it has most likely had a an english freewheel on it and you don't want to go back

pastorbobnlnh 

If you are looking for a similar freewheel, I have a fair selection of Shimano 600 6 speed freewheels. You can contact me through my website.

since6

JohnD thanks for the info on identifying the type of hub, it was a sunny day, can't miss them for a ride, so not much work on the bike. That's the next thing to take off the freewheel and look at the hub. And Pastorbob I will check out your website. It was a relief that free wheels are available, as last year I swapped out my Record Triple 8 speed for Record Triple 10 speed because 8 speed components were getting so hard to find, let alone the price. Love those two extra gears.