28 tooth sprocket for gearhub

Chalo said:

I am trying to find and purchase a 28 tooth sprocket, to
use on a 7 speed gearhub on my cargo sidehack. It must be
of the 3-splined pattern used on Sturmey-Archer, Sachs,
SRAM, and Shimano gearhubs and most coaster brake hubs. I
know such a thing exists, because I have one which is in
service on another bike.

Currently the cargo bike's primary gearing is 52-24. The
low gear is insufficient for serious hill climbing with a
passenger or other heavy load, and the top gear is higher
than strictly necessary for a craft of such idiosyncratic
handling qualities. Yet I am unable to diminish the size
of the front sprocket due to an unavoidable chain
interference issue.

Does anybody here know where a 28 tooth gearhub sprocket
can be found?

I've never seen one larger than the 24 we stock, but it is a
fairly trivial task to modify a Shimano cassette sprocket to
fit a 3-splined hub driver.

Can be done with a Dremel-type tool, though I usually prefer
to chuck a small grindstone into my drill press for this.

Sheldon "Where There's A Will..." Brown +--------------------------------------------------
+
| The less you bet, the more you lose if you win | --Alan
| Rudolph (_Trixie_) |
+--------------------------------------------------+ Harris
Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX
617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗
sheldonbrown.comsheldonbrown.comOpen ↗

"Sheldon Brown" wrote: (clip) Can be done with a Dremel-type
tool, (clip) ^^^^^^^^^^ Consider, also, the possibility of
welding the three spline center from another sprocket into a
28 tooth cog. Of course, this depends on having metal in the
right places on both pieces to permit good welds. If you
want to mail me the parts, I would be glad to do this for
you, for the cost of postage.

[email hidden] (Chalo) wrote in message news:<[email hidden]>...

Quoted message said:

I am trying to find and purchase a 28 tooth sprocket, to
use on a 7 speed gearhub on my cargo sidehack. It must be
of the 3-splined pattern used on Sturmey-Archer, Sachs,
SRAM, and Shimano gearhubs and most coaster brake hubs. I
know such a thing exists, because I have one which is in
service on another bike.

Currently the cargo bike's primary gearing is 52-24. The
low gear is insufficient for serious hill climbing with a
passenger or other heavy load, and the top gear is higher
than strictly necessary for a craft of such idiosyncratic
handling qualities. Yet I am unable to diminish the size
of the front sprocket due to an unavoidable chain
interference issue.

Does anybody here know where a 28 tooth gearhub sprocket
can be found?

Chalo Colina

From Sheldon's 3-speed page: sheldonbrown.comenglishOpen ↗
3.html#sturmey "It is also possible to modify Shimano
cassette sprockets with a Dremel grinder if you need
something bigger. This is not particularly difficult to do."

I would probably try to find an older Uniglide sprocket
instead of a Hyperglide sprocket due to the (slightly)
superior tooth profile.

Jeff