Atom Freewheel indexing.

meb said:

I’ve got a 6 speed Atom 14-28 freewheel on a friction shifting bike.
Want to upgrade that bike to 7 speed freewheel (friction shifting) and
move that freewheel to a 6 speed with SIS indexed shifting that has a
freewheel with tooth wear on the two smallest sprockets (chain measures
unworn, only found a single link with perceptible play).
The Atom freewheel has the word compact on it’s carrier body. Is it
SIS compatible?

Don't think so. A "compact 6" freewheel is simply one which fits into
the space of a 5 speed freewheel and avoids the need to spread the frame
from 120mm. Standard 6 speed (and 7 speed, which are all "compact"😉
used 126mm, you see.

meb said:

I’ve got a 6 speed Atom 14-28 freewheel on a friction shifting bike.
Want to upgrade that bike to 7 speed freewheel (friction shifting) and
move that freewheel to a 6 speed with SIS indexed shifting that has a
freewheel with tooth wear on the two smallest sprockets (chain measures
unworn, only found a single link with perceptible play).
The Atom freewheel has the word compact on it’s carrier body. Is it
SIS compatible?

No. If you expect decent shifting, buy the appropriate freewheel for the
derailleur you're using.

--

-John ([email hidden])

"meb" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I've got a 6 speed Atom 14-28 freewheel on a friction shifting bike....
Is it SIS compatible?

If the cog spacing on these matches 6-speed indexing, it will just be a
coincidence. I used these in the 70's. They were junk. There is a good
reason that the Japanese took over the freewheel market. Mechanically the
Atoms were poorly made and featured mediocre shifting due to primitive cog
profiles (Hyperglide is much much better). The spacers used on these likely
vary in width all over the map.

Do yourself a favor and throw it in the garbage. Buy a 6-speed Shimano HG20
freewheel. Costs about $12 where I shop.

meb said:

I've got a 6 speed Atom 14-28 freewheel on a friction shifting bike.
Want to upgrade that bike to 7 speed freewheel (friction shifting) and
move that freewheel to a 6 speed with SIS indexed shifting that has a
freewheel with tooth wear on the two smallest sprockets (chain measures
unworn, only found a single link with perceptible play).

If you have an Atom freewheel remover, why don't you try it, it cannot
hurt anything. Don't struggle to make it work, just give it a
short-term try and if it doesn't work then buy a modern freewheel. I
think that modern freewheels like sunrace will index and only cost
about $15. In the meantime, you might learn something new about
indexing with this experiment.

- Don Gillies
San Diego, CA

P.S. if it doesn't work, i've been looking for a compact atom
freewheel for a 1973 project bike of mine, and may be willing to buy
it from you - contact me off-list.

quote='Zog The Undeniable'meb said:

I’ve got a 6 speed Atom 14-28 freewheel on a friction shifting bike.
Want to upgrade that bike to 7 speed freewheel (friction shifting) and
move that freewheel to a 6 speed with SIS indexed shifting that has a
freewheel with tooth wear on the two smallest sprockets (chain measures
unworn, only found a single link with perceptible play).
The Atom freewheel has the word compact on it’s carrier body. Is it
SIS compatible?

Don't think so. A "compact 6" freewheel is simply one which fits into
the space of a 5 speed freewheel and avoids the need to spread the frame
from 120mm. Standard 6 speed (and 7 speed, which are all "compact"😉
used 126mm, you see.[/QUOTE]

Measured, the sprockets on the Atom compact 6 speed-they are about .2mm closer together than SIS indexed 6 speed (I notice Sheldon's page lists narrow 6 speed as having 124 mm dropouts).

I swapped rear wheels between the bikes and thus far am finding with indexed shifting I get a skip over the second largest or third largest sprockets. I'll play with adjustments to see if I can move the misalign from 2-3 to the small cog and make it work-I believe sprockt 3 is where proper align should be for this to have its best chance at working.

meb said:

Measured, the sprockets on the Atom compact 6 speed-they are about .2mm closer together than SIS indexed 6 speed (I notice Sheldon's page lists narrow 6 speed as having 124 mm dropouts).

I swapped rear wheels between the bikes and thus far am finding with indexed shifting I get a skip over the second largest or third largest sprockets. I'll play with adjustments to see if I can move the misalign from 2-3 to the small cog and make it work-I believe sprockt 3 is where proper align should be for this to have its best chance at working.

Came close on a couple of adjustmenst, but no exact match on indexing calibration that matches SIS.

Was thinking this freewheel might have a thread compatibliy issue if I shift it to an SIS bike. Anyone know if this is a French theaded freewheel?
This came off a Mavic wheel on a Peugot.

meb said:

Was thinking this freewheel might have a thread compatibliy issue if

I

Quoted message said:

shift it to an SIS bike. Anyone know if this is a French theaded
freewheel?
This came off a Mavic wheel on a Peugot.

Normally, the threading is stamped on the hub as well as on the
freewheel. Anyway, iirc an ISO freewheel will fit on a french threaded
hub.

meb said:

Quoted message said:

Was thinking this freewheel might have a thread compatibliy issue if
I shift it to an SIS bike. Anyone know if this is a French theaded
freewheel?
This came off a Mavic wheel on a Peugot.

If it's a Mavic hub, it's almost certainly ISO standard (_not_ French
thread.) French threading went extinct for medium/high-end bikes
sometime in the 1980s.

A well-intentioned poster wrote optimistically.

Quoted message said:

Normally, the threading is stamped on the hub as well as on the
freewheel.

That was true of Campagnolo hubs for a while, and some freewheels with
oddball (i.e. French or Italian) threading) but in most cases there is
no such marking.

Quoted message said:

Anyway, iirc an ISO freewheel will fit on a french threaded hub.

That part is absolutely false. Old French-thread freewheel threading is
34.7 mm diameter, whilst ISO/English freewheels are 1 3/8" (34.93 mm)
diameter.

There's also a mismatch in thread pitch.

Since the ISO freewheel is larger, you can fit it over a French thread
hub, but the thread engagement will be so poor that you'll strip the
threads almost immediately.

Sheldon "No Go" Brown
+----------------------------------------+
| Promote the institution of marriage: |
| Make it available to all adults! |
+----------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Sheldon Brown said:

meb said:

Quoted message said:

Was thinking this freewheel might have a thread compatibliy issue if
I shift it to an SIS bike. Anyone know if this is a French theaded
freewheel?
This came off a Mavic wheel on a Peugot.

If it's a Mavic hub, it's almost certainly ISO standard (_not_ French
thread.) French threading went extinct for medium/high-end bikes
sometime in the 1980s.

Maybe so, but Atom made a LOT of French-threaded freewheels for Peugeot;
chances are high he's got one. Peugeot also went pretty much extinct
(at least in USA) in the mid 80's so chances are even higher. OP didn't
say if it was a Mavic hub or Mavic rim so chances are still high.

Unfortunately, I've forgotten the original question now, but I suspect
the answer is "probably not".

--
My bike blog:
http://diabloscott.blogspot.com/

Diablo Scott said:

Maybe so, but Atom made a LOT of French-threaded freewheels for Peugeot;
chances are high he's got one. Peugeot also went pretty much extinct
(at least in USA) in the mid 80's so chances are even higher. OP didn't
say if it was a Mavic hub or Mavic rim so chances are still high.

Peugeots exported to the U.S. through normal wholesale channels
generally used ISO/English hubs/freewheels, at least if they had 630 mm
(27 inch) wheels.

These bikes did have French-size bottom brackets and headsets, but
usually went ISO/English for the hubs/freewhweels and also for the pedals.

Sheldon "http://sheldonbrown.com/velos" Brown
+--------------------------------------------------+
| Some of my brother's paintings may be seen at: |
| http://junila.com |
+--------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Sheldon Brown said:

Diablo Scott said:

Maybe so, but Atom made a LOT of French-threaded freewheels for
Peugeot; chances are high he's got one. Peugeot also went pretty much
extinct (at least in USA) in the mid 80's so chances are even higher.
OP didn't say if it was a Mavic hub or Mavic rim so chances are still
high.

Peugeots exported to the U.S. through normal wholesale channels
generally used ISO/English hubs/freewheels, at least if they had 630 mm
(27 inch) wheels.

These bikes did have French-size bottom brackets and headsets, but
usually went ISO/English for the hubs/freewhweels and also for the pedals.

I had a Peugeot (P8 I think... circa 1984), purchased new through a
normal bike shop that presumably got it through normal channels (they
were mostly a Peugeot shop) and it definitely had the French headset
with oddball stem size, 27" wheels with tires labeled "Michelin Bib
Sport 1" " (but were actually more like 1-1/4"😉 and an Atom 6-speed
freewheel with French FW threads (I'm SURE - that was one of the reasons
I later bought new wheels for it). In fact I never saw an Atom
freewheel that didn't have French threads (admittedly a small sample
size). Don't remember what kind of hub came with the bike but I think
it had Weinmann rims. And I'm still not sure what the OQ was.

Quoted message said:

Sheldon "http://sheldonbrown.com/velos" Brown

Welldone Sheldon, that bit about the Maillard Helicomatic hubs evoked
some memories. I note though, that the table at the bottom doesn't show
that Atom made freewheels.
--
My bike blog:
http://diabloscott.blogspot.com/

quote='Diablo Scott'Sheldon Brown said:

Diablo Scott said:

Maybe so, but Atom made a LOT of French-threaded freewheels for
Peugeot; chances are high he's got one. Peugeot also went pretty much
extinct (at least in USA) in the mid 80's so chances are even higher.
OP didn't say if it was a Mavic hub or Mavic rim so chances are still
high.

Peugeots exported to the U.S. through normal wholesale channels
generally used ISO/English hubs/freewheels, at least if they had 630 mm
(27 inch) wheels.

These bikes did have French-size bottom brackets and headsets, but
usually went ISO/English for the hubs/freewhweels and also for the pedals.

I had a Peugeot (P8 I think... circa 1984), purchased new through a
normal bike shop that presumably got it through normal channels (they
were mostly a Peugeot shop) and it definitely had the French headset
with oddball stem size, 27" wheels with tires labeled "Michelin Bib
Sport 1" " (but were actually more like 1-1/4"😉 and an Atom 6-speed
freewheel with French FW threads (I'm SURE - that was one of the reasons
I later bought new wheels for it). In fact I never saw an Atom
freewheel that didn't have French threads (admittedly a small sample
size). Don't remember what kind of hub came with the bike but I think
it had Weinmann rims. And I'm still not sure what the OQ was.

Quoted message said:

Sheldon "http://sheldonbrown.com/velos" Brown

Welldone Sheldon, that bit about the Maillard Helicomatic hubs evoked
some memories. I note though, that the table at the bottom doesn't show
that Atom made freewheels.
--
My bike blog:
http://diabloscott.blogspot.com/[/QUOTE]

OQ was whether the compact 6 Atom was close enought to SIS-6 to be adjustably compatible. During the experiment (which appears heading toward a poor compatibility answer per the .2mm/sprocket difference), a theading compatibity question occurred to me.

The hub is Maillard, has a 21 (I think-unless it's a strange font 27) stamped in it.

Quoted message said:

meb said:

Was thinking this freewheel might have a thread compatibliy issue if
shift it to an SIS bike. Anyone know if this is a French theaded
freewheel?
This came off a Mavic wheel on a Peugot.

Christoph Strauch said:

Normally, the threading is stamped on the hub as well as on the
freewheel. Anyway, iirc an ISO freewheel will fit on a french threaded
hub.

With difficulty, possibly fatally. A 34.85mm freewheel on a
35mm hub is not a good idea.

Unmarked freeweheels are country of origin. A blank Atom is
French, a blank Regina is Italian. Any mark is the other
thread. A Regina with a F (franchese) or an X is metric. An
Atom with an A (anglaise) or frequently a zero or an X is BSC.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971