I am hoping for a quick education on the obsolete and forgotten (except by you guys) art of freewheel cogset swapping.
Assuming you stay in one “speed” (e.g. dealing just with 6 speed freewheels), which brands’ cogs are compatible with which other brands? Can you, for example, put Zeus or Regina cogs on a Campagnolo freewheel body? Will Japanese and European bits co-exist?
Now suppose you have various freewheels and loose cogs from mixed “speeds”. Say a jumble of 6 and 7 speed. Can you put the 7 speed cogs onto the 6 speed bodies?
As a practical matter, would you bother to swap cogs anymore? Or is it usually better to simply buy different freewheels?
Basically, I bought an old bike with a 6 speed straight block, and I’m afraid my legs may not measure up. 42/17 low gear is sounding pretty daunting. I could find a larger cogs and swap out the existing 17T cog. Or I could look for a 6 speed freewheel with more humane gearing. Or I could buy a 7 speed freewheel, as I think (?) they will fit the 126mm spacing. The bike has friction shifting.
I think Shimano 600 and Dura-Ace freewheels have some interchangeable cogs,
having put a larger cog from one onto a racing version of the other. Regina,
Sachs-Maillard, and Everest (only CX series and Everest-alloy empirically) have
interchangeability. These claims are ignoring the 12 and 14 etc cogs which hold
everything on [ideally]. Two diameters of Maillard and Regina are identical,
although new Maillard has a fourth spline which would have to be ground off to
fit the regina. Regina alloy cogs have twice the splines but the same diameter.
Zeus and Campagnolo freewheels are absolutely incompatible within and without;
they have nonAl bodies like Regina although Campagnolo may use some Ti. This
means you have a long-lasting body and worn-out cogs. I recently saw an early
Maillard course alloy freewheel advert'd with same diameters mentioned and alloy
body, so that if you do a hard sprint at the end the pawls shear off all the
teeth, like an Everest. Freewheel cogs are kind of like printer ink, although
the Sachs-Maillard, which are distinct from Maillard (early) might go cheaper.
Like, if you've got a Regina bx or cx with one worn-out ratio, (assuming bx and
cx are like 600 and D-A, [although the lefty-thread big-cog old units probably
are standadized with contemporary Everests,]) it's worth buying a Sachs cog to
keep it going. And, like, Japanese and European bits can co-exist and even thrive,
but not on the same frame:[ The Sachs freewheels came in an axle-straining
8-speed which now might be cheap. (A French guy currently has a whole chart of
that brand up.) But Regina cogs are pricey,
AFAIK. All this is a lot better than
cold-setting your rear triangle, with the companion expense of getting a shop to
align your dropouts so you don't bend your freehub axles. I leave Suntour out of
this because they often have paper-thin spacers supplementing their conventional
ones. If you don't mind destroying the threads they might thread in the small
cog spot on others, DK. Very early on I tried at my LBS on Cape Cod to replace a
worn cog and got something of a hostile response; that "we were a family bike
shop." That guy didn't honor the Specialized hub warranty either. He was with
the program back then. I found this thread trying to figure out just one brand's
code, (the only info seen thus far is the French guy's ad, although charts have
popped up here and there, without measurements, of course.) I'm certainly not
saving this anywhere but the cloud.