can't removed cog from fixed gear wheel
WooGoogle
oil, then attacking with chain whip with helper bar, and am slowly but
surely tearing up the aluminum chain whip. I've tried braking on a
long steep hills using only the rear wheel and the front brake and
only succeeded in wearing out a rear tire. It's a shimano Dura Ace
steel cog and a Sovos hub. Would a small amount of heat (on which
part) help or hurt? Any other ideas?
Sheldon Brown
> Used wheel for commuting on some long steep hills. Tried penetrating
> oil, then attacking with chain whip with helper bar, and am slowly but
> surely tearing up the aluminum chain whip.
Somebody actually makes an _aluminum_ chain whip? No wonder it busted!
> I've tried braking on a
> long steep hills using only the rear wheel and the front brake and
> only succeeded in wearing out a rear tire. It's a shimano Dura Ace
> steel cog and a Sovos hub. Would a small amount of heat (on which
> part) help or hurt?
Most likely it would be counterproductive, because aluminum expands
twice e as much as steel wheel heated.
> Any other ideas?
Get a better chain whip.
Alternately, wrap a short length of old chain around the sprocket, and
grab both ends together in a vise on a sturdy workbench.
Sheldon "No Substitute For A Good, Well Mounted Vise" Brown
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A Muzi
news:39e72603.02042...@posting.google.com...
Since cogs are cheap, what about a disc grinder with a slitting disc? Many
coaster hub cogs until about 1960 had a partial slit so the cog could be
split apart if rusted in place on the threaded driver.
--
Andrew Muzi
http://www.yellowjersey.org
Open every day since 1 April 1971
Sheldon Brown
> Since cogs are cheap, what about a disc grinder with a slitting disc?
Yow! Have you ever found one that needed this? I haven't.
> Many
> coaster hub cogs until about 1960 had a partial slit so the cog could be
> split apart if rusted in place on the threaded driver.
Sorry, Andy, that wasn't the reason for the slit. It was to allow you
to replace a broken spoke without having to remove the sprocket. I've
seen old ads that touted this feature.
I believe this was a New Departure innovation, but I'm not sure about that.
Sheldon "Musty Old Magazines" Brown
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Steven Woo
wrote:
Grinder idea sounds promising since I don't have the vice Sheldon
recommended.
Soon Chung
hammer to give it short sharp knocks. that should free the cog up. Or like
Sheldon says, get a steel chain whip.
sc
A Muzi
in message news:3CCCC149...@sheldonbrown.com...
> I (A.M.) wrote:
> > Since cogs are cheap, what about a disc grinder with a slitting disc?
>
>
> Yow! Have you ever found one that needed this? I haven't.
>
> > Many
> > coaster hub cogs until about 1960 had a partial slit so the cog could be
> > split apart if rusted in place on the threaded driver.
>
>
> Sorry, Andy, that wasn't the reason for the slit. It was to allow you
> to replace a broken spoke without having to remove the sprocket. I've
> seen old ads that touted this feature.
>
> I believe this was a New Departure innovation, but I'm not sure about
that.
>
> Sheldon "Musty Old Magazines" Brown
Thanks. No I have not and I have never split a cog on a CB either (although
it's become common on Suntour cassette high gear cogs lately after the teeth
come off with a chain wrench). I surmised incorrectly it seems about the
cog slit. What I was thinking about was trying to minimize damage to the
aluminum thread as when very stuck pedals come out with the crank threads
still attached.
(I was also reminded of the wooden chain wrench thread on reading about the
aluminum one's failure!)
WooGoogle
Thanks, a good non-destructive idea. Now I just needs to finds me a
scrap piece of 2x4! I think maybe it's a steel chain whip, but I am
crushing the handle underneath the chain, whatever the handle is made
of. I'll do a magnet test if anyone is interested.
Phil Brown
hammer to give it short sharp knocks. that should free the cog up. >>
I use a piece of aluminium bar.
Phil Brown