"Re-gearing" Sturmey-Archer hubs

Does anyone know if it is possible (or even advisable!) to change the
gearing on a 3 speed sturmey archer hub? I have an old Hercules Balmoral,
picked up off eBay for a bargain price, for my GF that has a replacement hub
(1991 is the date on it). It works fine, but all the gears seem rather high
for this type of bike, so I wondered if it was possible to lower them at
all. I actually picked up a reconditioned "spare" 3 speed hub too, although
I've never changed a hub on a wheel before, so that could be a bit
challenging too. I'd love to have a go - after all, you never find out how
to do these things unless you try.

Thanks

Colin

Colin Reed wrote:
Does anyone know if it is possible (or even advisable!) to change the
gearing on a 3 speed sturmey archer hub? I have an old Hercules Balmoral,
picked up off eBay for a bargain price, for my GF that has a replacement hub
(1991 is the date on it). It works fine, but all the gears seem rather high
for this type of bike, so I wondered if it was possible to lower them at
all. I actually picked up a reconditioned "spare" 3 speed hub too, although
I've never changed a hub on a wheel before, so that could be a bit
challenging too. I'd love to have a go - after all, you never find out how
to do these things unless you try.

Thanks

Colin



remove wheel, pry of the snapring and lift of the cog. Fit a bigger one
and you might need a longer chain. Take care when refitting the
snapring,it's easy to sent it flying and or hurt your fingers.

--
/Marten

info(apestaartje)m-gineering(punt)nl

Colin Reed wrote:
Does anyone know if it is possible (or even advisable!) to change the
gearing on a 3 speed sturmey archer hub? I have an old Hercules Balmoral,
picked up off eBay for a bargain price, for my GF that has a replacement hub
(1991 is the date on it). It works fine, but all the gears seem rather high
for this type of bike, so I wondered if it was possible to lower them at
all.

If they're all a bit high, can't you just replace the rear sprocket with
one with a few more teeth? No need to mess with the hub at all. I'm not
an expert, but I have replaced the sprocket on my three-speed (with a new
same-size one, it was a bit worn), and it was a dead easy job. Hardest
part will probably be working out exactly what size sprocket you want.

-- PMM

On Wed, 23 Jul 2008 11:25:32 +0200,
M-gineering wrote:
Colin Reed wrote:
Does anyone know if it is possible (or even advisable!) to change the
gearing on a 3 speed sturmey archer hub? I have an old Hercules Balmoral,
picked up off eBay for a bargain price, for my GF that has a replacement hub
(1991 is the date on it). It works fine, but all the gears seem rather high
for this type of bike, so I wondered if it was possible to lower them at
all. I actually picked up a reconditioned "spare" 3 speed hub too, although
I've never changed a hub on a wheel before, so that could be a bit
challenging too. I'd love to have a go - after all, you never find out how
to do these things unless you try.

Thanks

Colin



remove wheel, pry of the snapring and lift of the cog. Fit a bigger one
and you might need a longer chain. Take care when refitting the
snapring,it's easy to sent it flying and or hurt your fingers.

Or change the chainring for a smaller one.

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t,"
and there was light.

http://www.woodall.me.uk/ http://www.locofungus.btinternet.co.uk/

Tim Woodall wrote:
On Wed, 23 Jul 2008 11:25:32 +0200,
M-gineering wrote:

remove wheel, pry of the snapring and lift of the cog. Fit a bigger one
and you might need a longer chain. Take care when refitting the
snapring,it's easy to sent it flying and or hurt your fingers.

Or change the chainring for a smaller one.

Or both...

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

"Tim Woodall" wrote in message
e.uk...
On Wed, 23 Jul 2008 11:25:32 +0200,
M-gineering wrote:
Colin Reed wrote:
Does anyone know if it is possible (or even advisable!) to change the
gearing on a 3 speed sturmey archer hub? I have an old Hercules
Balmoral,
picked up off eBay for a bargain price, for my GF that has a replacement
hub
(1991 is the date on it). It works fine, but all the gears seem rather
high
for this type of bike, so I wondered if it was possible to lower them at
all. I actually picked up a reconditioned "spare" 3 speed hub too,
although
I've never changed a hub on a wheel before, so that could be a bit
challenging too. I'd love to have a go - after all, you never find out
how
to do these things unless you try.

Thanks

Colin



remove wheel, pry of the snapring and lift of the cog. Fit a bigger one
and you might need a longer chain. Take care when refitting the
snapring,it's easy to sent it flying and or hurt your fingers.

Or change the chainring for a smaller one.

Tim.


Yes, both of these caused a "Doh!!" response, because on reflection they are
pretty bloddy obvious ;-)

I'm still quite interested about what goes on inside the hub, because the
one on the bike at the moment doesn't have much of a jump between 2nd and
3rd gears (it definitely changes, but they're both pretty "big" gears).
Fitting the other hub I've bought (or more likely building it into a new
wheel) is something that will take a relative beginner to all things
mechanicky quite a long time! I understand now from a link off the Sheldon
Brown website that if you dismantle a Sturmey Archer 3 speed hub you
actually take the workings out, leaving the outer hub still in the wheel, so
no need for wheel building/truing. I still run the risk of leaving my GF
with a non-operational bike if I try this without having a contingency plan
(I suppose that plan being a trip to the LBS).

Colin

Colin Reed wrote:
I'm still quite interested about what goes on inside the hub, because the
one on the bike at the moment doesn't have much of a jump between 2nd and
3rd gears (it definitely changes, but they're both pretty "big" gears).
Fitting the other hub I've bought (or more likely building it into a new
wheel) is something that will take a relative beginner to all things
mechanicky quite a long time!

Er, assuming they're both AW hubs (the most common sort) the ratios
will be exactly the same -- 2nd is direct drive, 1st is 3/4 of that
and 2nd is 4/3 of it. If you just want to dismantle one for the fun
of it do that to the spare and leave the one on the bike alone :-)

http://www.sheldonbrown.com/sturmey-archer.html shows you where the
model type is stamped and gives the ratios for other models on the
off chance you have a rare one.

-- PMM

Colin Reed wrote:

I'm still quite interested about what goes on inside the hub, because the
one on the bike at the moment doesn't have much of a jump between 2nd and
3rd gears (it definitely changes, but they're both pretty "big" gears).

The workings of the Sturmey are (I think) rather wonderful.
It's a sun - planet - annulus arrangement (you'll have to look up
epicyclic gears on wikipedia to get a decent picture If you don't know
what that is).
The sun is always stationary and fixed to the axle.
The planets are in a cage that has a ratchet coupling to the outside of
the hub.
The annulus has a ratchet coupling to the outside of the hub too.

The planet gears are always engaged.

In third gear the cog drives the planet cage and, since the annulus will
then be rotating faster, the ratchet arrangement means that the annulus
drives the outside of the hub.

In second gear the cog drives the annulus and, again because of the
ratchet arrangement, the annulus drives the outside of the hub.

In first gear the the cog drives the annulus but the ratchet on the
annulus is inhibited from connecting to the hub this means that the
planet cage now drives the outside of the hub.

If you take it apart you'll see how all this is achieved, and why
there's a 'neutral' between the second and third gear.

Roger Thorpe

Roger Thorpe wrote:
Colin Reed wrote:

I'm still quite interested about what goes on inside the hub, because
the one on the bike at the moment doesn't have much of a jump between
2nd and 3rd gears (it definitely changes, but they're both pretty
"big" gears).

The workings of the Sturmey are (I think) rather wonderful.
It's a sun - planet - annulus arrangement (you'll have to look up
epicyclic gears on wikipedia to get a decent picture If you don't know
what that is).
The sun is always stationary and fixed to the axle.
The planets are in a cage that has a ratchet coupling to the outside of
the hub.
The annulus has a ratchet coupling to the outside of the hub too.

The planet gears are always engaged.

In third gear the cog drives the planet cage and, since the annulus will
then be rotating faster, the ratchet arrangement means that the annulus
drives the outside of the hub.

In second gear the cog drives the annulus and, again because of the
ratchet arrangement, the annulus drives the outside of the hub.

In first gear the the cog drives the annulus but the ratchet on the
annulus is inhibited from connecting to the hub this means that the
planet cage now drives the outside of the hub.

If you take it apart you'll see how all this is achieved, and why
there's a 'neutral' between the second and third gear.

Roger Thorpe

There hasn't been a neutral between normal and high gear for a number of
years now. SunRace/SA solved that problem (SA had something on the
drawing board decades ago but it was vetoed by management), as well as
moving to aluminium shells which reduce the spoke breakage problem at
the elbow. With hindsight, the Taiwanese buyout was the best thing that
could have happened for SA products.

The important thing with a 3-speed SA hub is that "normal", or "second"
gear, is direct drive because the planetary gears aren't transmitting
any drive. This makes it the most efficient, and therefore you should
choose the sprocket size carefully to ensure you spend as much time as
possible in that gear. 59" works for me.

Sadly the newer SunRace/SA hubs use grease lubrication rather than oil.
It's cleaner, but not quite as efficient, and when the grease gets
old, dry or contaminated, this means a full stripdown.

In article , Zog The Undeniable wrote:

There hasn't been a neutral between normal and high gear for a number of
years now. SunRace/SA solved that problem (SA had something on the
drawing board decades ago but it was vetoed by management)

I have a vague memory of reading that older SA hubs didn't have the problem
but that when the AW was introduced in 1936 it was designed to be cheaper
to produce. But Google doesn't back me up, so maybe I imagined it.

http://newsgroups.derkeiler.com/Arch.../msg00810.html
gives the part you need to change to get rid of the neutral on an AW.
See also http://www.bikeforums.net/archive/in.../t-405862.html