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Main
Date: 01 Jul 2007 06:23:25
From: D'ohBoy
Subject: Shaping Cassette Teeth
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I have been getting some annoying noise from my new Chorus cassette's
smallest cog (13t) - and as those who dare to read my drivel know,
this is a major issue for me.
So I try flipping the chain end for end. Not the solution - noise
seems to come once per revolution of the cog. Can't see anything
going on spinning the crank backwards, so I flip the bike and slowly
turn the crank while observing the chain.
Huh. At one point, the chain actually hangs up (just slightly) on one
tooth due to the lateral force from the relationship between the big
ring in the front and the cog in the rear combined with the existing
shaping of the teeth. There is a significant transition between the
lateral positioning of the peak of the tooth from inboard to outboard
over the course of two teeth. The release of the chain from this
slightly caught position is causing some jangling. And no doubt
excessive wear on the chain.
Please note that the tooth is still within the confines of the limits
of the overall cog, i.e., it doesn't appear to be bent.
So, my question is: Is it reasonable to take a file or a dremel to
this tooth and give it a slight taper at one end so that the chain
slides over it, rather than hanging? Or perhaps put a slight bend on
it so that the transition between tooth peak location is not so
abrupt?
Since I use this cog infrequently, I am not concerned about shortening
its life and note as well, other teeth on this cog are significantly
thinner than this one.
TIA
D'ohBoy
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Date: 02 Jul 2007 02:55:43
From: joseph.santaniello@gmail.com
Subject: Re: Bent Der Hanger, Not Cassette Tooth WAS: Re: Shaping Cassette Teeth
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On Jul 2, 4:11 am, D'ohBoy <peteng...@yahoo.com > wrote:
> Hi, Joseph -
>
> Well, after giving one of my other wheelsets a go - might as well
> exhaust all options before taking a grinder to things - I found that
> it had something to do with the bike, not the cassette.
>
> This became apparent after a wheel that did not cause this noise on my
> secondary bike caused the noise on primary bike. So what could be
> causing the noise?
>
> Long story short, I had a bent der hanger. Which is weird, because I
> actually 'unbent' it last year as well. Can you coldset aluminum? I
> have beaten a moderately taco-ed OP rim back into round, and bent this
> hanger back into position before. Why would it go out of position
> over time? I don't believe the bike has ever been knocked over,
> definitely has not been crashed, and I never lay it drivetrain side
> down.
>
> Huh, guess I'll have to keep an eye on it.
>
> D'ohBoy
Hmm. Maybe my wife's was (is?) bent too, but in this case it seemed
more like a chainline and resultant angle of the chain from the
different chainwheel sizes that was at fault. Glad you got it worked
out!
Joseph
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Date: 01 Jul 2007 19:11:52
From: D'ohBoy
Subject: Bent Der Hanger, Not Cassette Tooth WAS: Re: Shaping Cassette Teeth
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Hi, Joseph -
Well, after giving one of my other wheelsets a go - might as well
exhaust all options before taking a grinder to things - I found that
it had something to do with the bike, not the cassette.
This became apparent after a wheel that did not cause this noise on my
secondary bike caused the noise on primary bike. So what could be
causing the noise?
Long story short, I had a bent der hanger. Which is weird, because I
actually 'unbent' it last year as well. Can you coldset aluminum? I
have beaten a moderately taco-ed OP rim back into round, and bent this
hanger back into position before. Why would it go out of position
over time? I don't believe the bike has ever been knocked over,
definitely has not been crashed, and I never lay it drivetrain side
down.
Huh, guess I'll have to keep an eye on it.
D'ohBoy
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Date: 01 Jul 2007 12:54:38
From: joseph.santaniello@gmail.com
Subject: Re: Shaping Cassette Teeth
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On Jul 1, 3:23 pm, D'ohBoy <peteng...@yahoo.com > wrote:
> I have been getting some annoying noise from my new Chorus cassette's
> smallest cog (13t) - and as those who dare to read my drivel know,
> this is a major issue for me.
>
> So I try flipping the chain end for end. Not the solution - noise
> seems to come once per revolution of the cog. Can't see anything
> going on spinning the crank backwards, so I flip the bike and slowly
> turn the crank while observing the chain.
>
> Huh. At one point, the chain actually hangs up (just slightly) on one
> tooth due to the lateral force from the relationship between the big
> ring in the front and the cog in the rear combined with the existing
> shaping of the teeth. There is a significant transition between the
> lateral positioning of the peak of the tooth from inboard to outboard
> over the course of two teeth. The release of the chain from this
> slightly caught position is causing some jangling. And no doubt
> excessive wear on the chain.
>
> Please note that the tooth is still within the confines of the limits
> of the overall cog, i.e., it doesn't appear to be bent.
>
> So, my question is: Is it reasonable to take a file or a dremel to
> this tooth and give it a slight taper at one end so that the chain
> slides over it, rather than hanging? Or perhaps put a slight bend on
> it so that the transition between tooth peak location is not so
> abrupt?
>
> Since I use this cog infrequently, I am not concerned about shortening
> its life and note as well, other teeth on this cog are significantly
> thinner than this one.
>
> TIA
>
> D'ohBoy
I did just as you describe to my wife's 9-speed Mirage cassette. I
used an old rusty hand file.
Joseph
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