expanding gear ratio on 3-speed revisited

On Feb 21, 6:00 am, dabac dabac.354...@no-
mx.forums.cyclingforums.com wrote:
A Muzi Wrote:

Tom Sherman Wrote:
Today you can buy the same thing brand new, except with an 8 or
9-speed
cassette attached to the 3-speed hub - see SRAM DualDrive.

dabac wrote:
But is there anything like that available today that would fit the
sprocket thread of an old S-A hub?

any freewheel, just block the body.

Wow, really? Like a low-end Shimano 7-spd freehub?
I really gotta get my eyesight calibrated in that case, 'cause the
diameter of the hub sure looked way too large for that to me.

--
dabac

FreeWHEEL, not freeHUB. There's a difference.

- Frank Krygowski

Tom Sherman Wrote:
Today you can buy the same thing brand new, except with an 8 or
9-speed
cassette attached to the 3-speed hub - see SRAM DualDrive.

dabac wrote:
But is there anything like that available today that would fit the
sprocket thread of an old S-A hub?

A Muzi Wrote:
any freewheel, just block the body.

dabac wrote:
Wow, really? Like a low-end Shimano 7-spd freehub?
I really gotta get my eyesight calibrated in that case, 'cause the
diameter of the hub sure looked way too large for that to me.

Freewheel, not freehub.

Sturmey Archer threaded drivers are BSC 1.370x24 and accept a standard
track cog or freewheel.

A Shimano Seven freewheel is a poor choice as the body height is huge
and the right side spacing will be excessive (c.f. Jobst's current
comment on broken 1034/P rear hub axles) but it will screw on just fine.

n.b. you'll have to disassemble the hub and slip the driver over
something (like a wrench held in a vise) to unscrew whatever cog is on
it now. If you braze the body together first, you won't have to take the
hub apart twice. As always, measure before jumping into the deep end.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi Wrote:
Freewheel, not freehub.

Ah, sorry 'bout that. The similarity of the names and the jobs they
both do trip me up sometimes.

A Muzi Wrote:
A Shimano Seven freewheel is a poor choice as the body height is huge
and the right side spacing will be excessive

But there's a guy in 'this thread'
(http://www.cyclingforums.com/t442815.html) that has discovered that
there is a stock bearing that's a nice press fit into the freewheel,
which would improve axle support.
Picture of improved axle assembly 'he'
(http://www.cyclingforums.com/attachm...achmentid=9032) . Axle
and freewheel 'he'
(http://www.cyclingforums.com/attachm...achmentid=9033)
I thought I might have a go at it.

A Muzi Wrote:
Sturmey Archer *threaded drivers* are BSC 1.370x24 and accept a
standard track cog or freewheel.

n.b. you'll have to disassemble the hub and slip the driver over
something (like a wrench held in a vise) to unscrew whatever cog is on
it now.

I'm sorry, but I'm not sure I'm following you. I'm as certain as can be
w/o having the hub in my lap and a caliper in my hand that the place
where the current sprocket is sitting has a larger diameter than that.
Is the threaded driver a part that's more internal to the hub?
I.e. are we talking about removing the stock sprocket and sticking
another freewheel on there, or are we talking about replacing a larger
part of the hub's right side?
And is a Shimano 7-spd frewheel also considered a standard freewheel?

Either way, I sure appreciate the help I'm getting, thanks.


--
dabac

A Muzi Wrote:
Freewheel, not freehub.

Ah, sorry 'bout that. The similarity of the names and the jobs they
both do trip me up sometimes.

A Muzi Wrote:
A Shimano Seven freewheel is a poor choice as the body height is huge
and the right side spacing will be excessive

dabac wrote:
But there's a guy in 'this thread'
(http://www.cyclingforums.com/t442815.html) that has discovered that
there is a stock bearing that's a nice press fit into the freewheel,
which would improve axle support.
Picture of improved axle assembly 'he'
(http://www.cyclingforums.com/attachm...achmentid=9032) . Axle
and freewheel 'he'
(http://www.cyclingforums.com/attachm...achmentid=9033)
I thought I might have a go at it.

A Muzi Wrote:
Sturmey Archer *threaded drivers* are BSC 1.370x24 and accept a
standard track cog or freewheel.
n.b. you'll have to disassemble the hub and slip the driver over
something (like a wrench held in a vise) to unscrew whatever cog is on
it now.

dabac wrote:
I'm sorry, but I'm not sure I'm following you. I'm as certain as can be
w/o having the hub in my lap and a caliper in my hand that the place
where the current sprocket is sitting has a larger diameter than that.
Is the threaded driver a part that's more internal to the hub?
I.e. are we talking about removing the stock sprocket and sticking
another freewheel on there, or are we talking about replacing a larger
part of the hub's right side?
And is a Shimano 7-spd frewheel also considered a standard freewheel?
Either way, I sure appreciate the help I'm getting, thanks.

Sturmey threaded drivers were all 1.370x24t and you indicated, I
believe, that you had one. After 1932, Sturmey introduced splined
drivers (originally 8-spline for the K series), the current three-spline
format being most common.

If you do have a threaded driver, you'll need to disassemble the hub to
hold the driver while you unscrew whatever cog is on it now.

Correct, there are no modern freewheels with Metric or Italian
threading, now all BSC 1.370 x24:
http://www.yellowjersey.org/FWTHREAD.JPG

I'm not convinced a bearing slipped over your axle will help much in
this case (right side spacing from ~10mm to ~28mm) but what the heck.

If you intend a 3x7, the SRAM setup Tom suggested is a great answer.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi Wrote:

Sturmey threaded drivers were all 1.370x24t and you indicated, I
believe, that you had one. After 1932, Sturmey introduced splined
drivers (originally 8-spline for the K series), the current
three-spline
format being most common.

If you do have a threaded driver, you'll need to disassemble the hub
to
hold the driver while you unscrew whatever cog is on it now.

Previously I've only looked at the wheel while in the frame, but
yesterday I removed it and let the hub spend some quality time with a
wire brush.
Once this treatment had freed the hub from the near-petrified
accumulation of old lube and road dust it became evident that I haven't
got a threaded driver.
It's got 3 splines, and the sprocket is locked in place with a
circlip.

So, barring some serious machining, I guess I'm all out of luck in
terms of adding a rear cluster. Which isn't entirely impossible, as the
diameter of the splined bit seems to be a decent match for the
35-something mm diameter of Shimano freewheels...

I did come up with a production stamp, so I believe the hub was made in
1982.(whatever good that would do me..)


--
dabac

On Feb 25, 7:35 am, dabac dabac.35c...@no-
mx.forums.cyclingforums.com wrote:

Previously I've only looked at the wheel while in the frame, but
yesterday I removed it and let the hub spend some quality time with a
wire brush.
Once this treatment had freed the hub from the near-petrified
accumulation of old lube and road dust it became evident that I haven't
got a threaded driver.
It's got 3 splines, and the sprocket is locked in place with a
circlip.

So, barring some serious machining, I guess I'm all out of luck in
terms of adding a rear cluster.

You may be able to find a threaded driver for a S-A hub. I found one
in a wonderful, unfashionable bike shop: http://www.citybikes.coop/

Try checking the kinds of bike shops that are more into utility bikes,
old bikes, and keeping bikes running, as opposed to the ones whose
stock is all advertised in Buycycling magazine.

- Frank Krygowski

On Feb 25, 12:35*pm, dabac dabac.35c...@no-
mx.forums.cyclingforums.com wrote:

Previously I've only looked at the wheel while in the frame, but
yesterday I removed it and let the hub spend some quality time with a
wire brush.
Once this treatment had freed the hub from the near-petrified
accumulation of old lube and road dust it became evident that I haven't
got a threaded driver.
It's got 3 splines, and the sprocket is locked in place with a
circlip.

So, barring some serious machining, I guess I'm all out of luck in
terms of adding a rear cluster. Which isn't entirely impossible, as the
diameter of the splined bit seems to be a decent match for the
35-something mm diameter of Shimano freewheels...

With a bit of grinding it is possibie to fit two dished Freehub
sprockets back-to-back on that driver. Back in the '80's you could get
adaptors that carried three sprockets. Any more would require dishing
the wheel and extending the axle. Also, the largest sprocket was about
18T, so for low gears you need a 36T chainring or less.

Far simpler to use a cheap triple chainset instead.

dabac dabac.35c...@no- mx.forums.cyclingforums.com wrote:
Previously I've only looked at the wheel while in the frame, but
yesterday I removed it and let the hub spend some quality time with a
wire brush.
Once this treatment had freed the hub from the near-petrified
accumulation of old lube and road dust it became evident that I haven't
got a threaded driver.
It's got 3 splines, and the sprocket is locked in place with a
circlip.
So, barring some serious machining, I guess I'm all out of luck in
terms of adding a rear cluster. Which isn't entirely impossible, as the
diameter of the splined bit seems to be a decent match for the
35-something mm diameter of Shimano freewheels...

JennyB wrote:
With a bit of grinding it is possibie to fit two dished Freehub
sprockets back-to-back on that driver. Back in the '80's you could get
adaptors that carried three sprockets. Any more would require dishing
the wheel and extending the axle. Also, the largest sprocket was about
18T, so for low gears you need a 36T chainring or less.

Far simpler to use a cheap triple chainset instead.

Almost.
Two dished Sturmey sprockets will fit (without the RMB127 spacers), one
facing in and the other facing out. Sturmey are 13 through 21 (no 20)
the smallest (13~16) being flat, not bevelled. Other brands go to 24t.

Shimano format freehub type sprockets may be easily modified to fit,
noting that the spline area engagement is less and that these are not
beveled at all so spacers are required.

Modern derailleurs don't have clearance for 1/8 chain, another detail.

The Cyclo Six and Nine dealer kits were crude, but dirt cheap and quite
effective. Raleigh sold the last of them in 1977. Making up everything
from scratch is more tedious (certainly possible) and does have plenty
of little hurdles.

To Dabac, the SA driver is cyanide hardened steel and the relieved area
is only about 32mm. It would have to be annealed, splatter welded,
threaded and hardened again. Big diesel shops do that work for
crankshafts and cams but not cheaply! You'd do better to buy a threaded
driver. Even another gearbox with a threaded driver in it is much
cheaper than threading these!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi Wrote:
... the SA driver is cyanide hardened steel...

Great info, thanks. Now I don't even have to think about putting a file
to it as a crude hardness test.

A Muzi Wrote:
It would have to be annealed, splatter welded,
threaded and hardened again.

Which would have been fun, but way OTT for something like this.

A Muzi Wrote:
You'd do better to buy a threaded
driver. Even another gearbox with a threaded driver in it is much
cheaper than threading these! Are all drivers created equal? Any pointers on what to look for?
I'm not adverse to a certain amount of speculating, but I'm not too
keen on the thought of shopping blindly either.

As far as I can tell the hub I've got is the same as in this
brochuhttp://www.sturmey-archerheritage.co...s/view-133.pdf

Yesterday I was looking at a dirt cheap freewheel hub, with the
threaded part as a crude cup. Something I probably could swing in my
home shop is to stick the S-A driver in the lathe, set it spinning and
then get to work with the big angle grinder. It'd be noisy and messy but
I reckon I could get the driver narrowed down enough for the threaded
part from the sacrifical hub to fit over the stump. With such a large
area I believe a fairly low temperature solder would be strong enough to
hold it in place w/o destroying the temper of the metal.


--
dabac