garage sale GT said:
It's nonstandard. I don't know of one bigger than 25T.
YOU will probably know the answer to
this ...
Are the Cogs which Sturmey-Archer hubs use
interchangeable with the ones which the SACHS 3-speed hubs and/or Shimano 3-speed hubs use?
Ditto on the question for their other internally geared hubs.
Well,
if THAT is the case,
then (
based on having done so, myself), then YOU
/anyone can cannibalize almost any size Cog from a SHIMANO Freehub-based Cassette and sleeve it onto the 3-speed hub ...
That apparently means that as large as a 42t Cog can theoretically be be used on a 3-speed hub, now ...
And/Or, as small as a 12t Cog, too!
If a person has the energy, they can even file out the excess material from an 11t (
final) Cog.
Yes, most Freehub Cogs are ramped ... that should not be a problem if the proper chain tension is maintained.
With a Sachs hub, I simply filed away (
with a half round file) some of the extra splines so that the THREE mating splines remained ... the three remaining splines were then rounded off with a hand file (
if I didn't use the same half round file, then it was a triangular rat tail) to fit the hub's receiving grooves AND spacers were initially used to take up the
slack ...
There is enough slack to install TWO Cogs + a spacer and thereby make it possible to have two different size Cogs if you use a narrower (
e.g., Sedis narrow width ... a 9-speed Shimano chain will work), Road chain ...
Basically, a single-sided Flip-Flop option OR a derailleur can be used to move the chain & take up the excess chain ... that is, just loosen the bolts & slide the hub back-or-forth to adjust the chain tension.
Currently, I have a Sachs hub configured with two Shimano Cogs + a spacer ...
I don't have the wheel in front of me & my memory is (
apparently!) fading, but a 22t & a 15t come to mind would have been chosen because I believe that I had calculated that they would subsequently yield the equivalent of a ~12t on the high end & a ~27t on the low end.
By my reckoning, a "modern" Shimano rear derailleur can handle an 8t step between
ramped Cogs without any problem; so, a 3-speed hub can be a 6-speed hub & a 5-speed hub can be a 10-speed hub.
Depending on the inner diameter of the Cogs which Shimano uses on their 11-speed Alfine hub, those could become a 22-speed hub ...
et cetera.