Cycling Equipment · Public discussion

Confusing rubbing

Smmb · 2004-05-12T14:02:48+00:00

This is a multi-part message in MIME format. ------=_NextPart_000_000D_01C43839.259464F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Just got back in from a nice ride, with a new "problem". The big ring = rubs the front derailleur. Kind of normal, but with a twist. This only = happens every SECOND revolution. I first noticed it while in big/little = on a 2% incline, while standing. So, I sat. No change. Not each = revolution, that's the screwy part, each other revolution. I figured I was compensating - that my unconscious reaction was to let = up on a downstroke when the previous stroke brought on the noise. Not = true, as this happened standing, sitting, and after I began to test for = it, it happened in the smallest cog and the next one, at any RPM and = pretty much with a variety of pedal pressures. Checked the chainring bolts, the crank bolts, have not yet looked at the = BB. Should I just hope that it changes to EVERY revolution, and then = fix that ?? :-) But every second revolution - this really has me = staring blankly. Who can figure this one out ? --=20 Sandy Paris FR ******* La vie, c'est comme une bicyclette,=20 il faut avancer pour ne pas perdre l'=E9quilibre. =20 -- Einstein, A. ------ =_NextPart_000_000D_01C43839.259464F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Just got back in from a nice ride, with = a new=20 "problem". The big ring rubs the front derailleur. Kind of = normal,=20 but with a twist. This only happens every SECOND revolution. = I first=20 noticed it while in big/little on a 2% incline, while standing. = So, I=20 sat. No change. Not each revolution, that's the screwy part, = each=20 other revolution. I figured I was compensating - that my = unconscious=20 reaction was to let up on a downstroke when the previous stroke brought = on the=20 noise. Not true, as this happened standing, sitting, and after I = began to=20 test for it, it happened in the smallest cog and the next one, at any = RPM and=20 pretty much with a variety of pedal pressures. Checked the chainring bolts, the crank = bolts, have=20 not yet looked at the BB. Should I just hope that it changes to = EVERY=20 revolution, and then fix that ?? :-) But every second=20 revolution - this really has me staring blankly. Who can figure this one out ? --=20 Sandy Paris FR ******* La vie, c'est comme une bicyclette, = il faut=20 avancer pour ne pas perdre l'=E9quilibre. -- Einstein,=20 A. ------=_NextPart_000_000D_01C43839.259464F0--

Started by Smmb · 12 May 2004 · Last activity 13 May 2004 · 6 posts · 434 views

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01 / Original postConfusing rubbingSmmb · 12 May 2004 02 / This pagePosts 1–6Page 1 of 1 · chronological order 03 / Latest replyPost #6A Muzi · 13 May 2004

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Original section: Cycling Equipment
Published: 12 May 2004
Last activity: 13 May 2004
Original author: Smmb
Posts: 6
Discussion status: Public discussion
Total views: 434
Views / 30 days: 0
Topics: Chainrings Front derailleurs Rear derailleurs

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Original post
Smmb
Archived post

12 May 2004, 14:02 UTC #1

This is a multi-part message in MIME format.
------=_NextPart_000_000D_01C43839.259464F0 Content-Type:
text/plain; charset="iso-8859-1" Content-Transfer-Encoding:
quoted-printable
Just got back in from a nice ride, with a new "problem". The
big ring = rubs the front derailleur. Kind of normal, but
with a twist. This only = happens every SECOND revolution. I
first noticed it while in big/little = on a 2% incline,
while standing. So, I sat. No change. Not each = revolution,
that's the screwy part, each other revolution.
I figured I was compensating - that my unconscious reaction
was to let = up on a downstroke when the previous stroke
brought on the noise. Not = true, as this happened standing,
sitting, and after I began to test for = it, it happened in
the smallest cog and the next one, at any RPM and = pretty
much with a variety of pedal pressures.
Checked the chainring bolts, the crank bolts, have not yet
looked at the = BB. Should I just hope that it changes to
EVERY revolution, and then = fix that ?? :-) But every
second revolution - this really has me = staring blankly.
Who can figure this one out ? --=20 Sandy Paris FR
*******
La vie, c'est comme une bicyclette,=20 il faut avancer pour
ne pas perdre l'=E9quilibre. =20 -- Einstein, A. ------
=_NextPart_000_000D_01C43839.259464F0 Content-Type:
text/html; charset="iso-8859-1" Content-Transfer-Encoding:
quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0
Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-
Type content=3D"text/html; = charset=3Diso-8859-1"> <META
content=3D"MSHTML 6.00.2800.1400" name=3DGENERATOR>
<STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Just got back in from a
nice ride, with = a new=20 "problem". The big
ring rubs the front derailleur. Kind of =
normal,=20 but with a twist. This only happens
every SECOND revolution. = I first=20 noticed
it while in big/little on a 2% incline, while
standing. = So, I=20 sat. No
change. Not each revolution, that's the screwy
part, = each=20 other revolution.</FONT></DIV>
<DV><FONT face=3DArial size=3D2></FONT> </DIV>
<DVI><FONT face=3DArial size=3D2>I figured I was
compensating - that my = unconscious=20 reaction was
to let up on a downstroke when the previous stroke
brought = on the=20 noise. Not true, as this
happened standing, sitting, and after I = began to=20
test for it, it happened in the smallest cog and the
next one, at any = RPM and=20 pretty much with a
variety of pedal pressures.</FONT></DIV>
<DVII><FONT face=3DArial size=3D2></FONT> </DIV>
<DVIII><FONT face=3DArial size=3D2>Checked the chainring
bolts, the crank = bolts, have=20 not yet looked at
the BB. Should I just hope that it changes to =
EVERY=20 revolution, and then fix that ??
:-) But every second=20 revolution - this
really has me staring blankly.</FONT></DIV>
<DIX><FONT face=3DArial size=3D2></FONT> </DIV>
<DX><FONT face=3DArial size=3D2>Who can figure this one
out ?<BR>--=20 <BR>Sandy<BR>Paris
FR</FONT></DIV>
<DXI> </DIV>
<DXII><FONT face=3DArial size=3D2>*******</FONT></DIV>
<DXIII> </DIV>
<DXIV><FONT face=3DArial size=3D2>La vie, c'est comme une
bicyclette, = <BR>il faut=20 avancer pour ne pas
perdre l'=E9quilibre. <BR>-- Einstein,=20
A.</FONT></DIV></BODY></HTML>
------=_NextPart_000_000D_01C43839.259464F0--

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daveornee
Archived post

12 May 2004, 15:43 UTC #2

Quoted post said:
Originally posted by Smmb
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Just got back in from a nice ride, with a new "problem". The
big ring = rubs the front derailleur. Kind of normal, but
with a twist. This only = happens every SECOND revolution. I
first noticed it while in big/little = on a 2% incline,
while standing. So, I sat. No change. Not each = revolution,
that's the screwy part, each other revolution.

I figured I was compensating - that my unconscious reaction
was to let = up on a downstroke when the previous stroke
brought on the noise. Not = true, as this happened standing,
sitting, and after I began to test for = it, it happened in
the smallest cog and the next one, at any RPM and = pretty
much with a variety of pedal pressures.

Checked the chainring bolts, the crank bolts, have not yet
looked at the = BB. Should I just hope that it changes to
EVERY revolution, and then = fix that ?? :-) But every
second revolution - this really has me = staring blankly.

Who can figure this one out ? --=20 Sandy Paris FR

*******

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Maybe something in the chain itself in combination with a slightly bent chain ring. If the chain abnormality comes around every other revolution and the chain ring has a slight outward bend; this combination pushes the chain as far out as it goes.
Are you using some kind of chain joining link?
What did you change or what happened before this started to happen?
How many links in the chain and how many teeth in the large chain ring? ... (106 links and 53 teeth maybe??)

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S O R N I
Archived post

12 May 2004, 16:00 UTC #3

SMMB said:
Just got back in from a nice ride, with a new "problem".
The big ring rubs the front derailleur. Kind of normal,
but with a twist. This only happens every SECOND
revolution. I first noticed it while in big/little on a 2%
incline, while standing. So, I sat. No change. Not each
revolution, that's the screwy part, each other revolution.
I figured I was compensating - that my unconscious
reaction was to let up on a downstroke when the previous
stroke brought on the noise. Not true, as this happened
standing, sitting, and after I began to test for it, it
happened in the smallest cog and the next one, at any RPM
and pretty much with a variety of pedal pressures.
Checked the chainring bolts, the crank bolts, have not yet
looked at the BB. Should I just hope that it changes to
EVERY revolution, and then fix that ?? :-) But every
second revolution - this really has me staring blankly.
Who can figure this one out ?
My guess: it's the chain's quick-link connection. (My PC-99
is noisier than its Shimano predecessor.)
Bill "if it was the ring then it would do it every rev" S.

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Smmb
Archived post

12 May 2004, 17:06 UTC #4

" S o r n i" <[email hidden]> a écrit dans le message de :
"]news:[email hidden]...
Quoted message said:
SMMB said:
Just got back in from a nice ride, with a new "problem".
The big ring rubs the front derailleur. Kind of normal,
but with a twist. This only happens every SECOND
revolution. I first noticed it while in big/little on a
2% incline, while standing. So, I sat. No change. Not
each revolution, that's the screwy part, each other
revolution.
I figured I was compensating - that my unconscious
reaction was to let up on a downstroke when the previous
stroke brought on the noise. Not true, as this happened
standing, sitting, and after I began to test for it, it
happened in the smallest cog and the next one, at any
RPM and pretty much with a variety of pedal pressures.
Checked the chainring bolts, the crank bolts, have not
yet looked at the BB. Should I just hope that it changes
to EVERY revolution, and then fix that ?? :-) But every
second revolution - this really has me staring blankly.
Who can figure this one out ?
My guess: it's the chain's quick-link connection. (My PC-
99 is noisier than its Shimano predecessor.)
Bill "if it was the ring then it would do it every rev" S.

OOOOOHH!! Yeah ! The period is about right, I see ! Just one
thing - no quick link on my C9 chain.... But it could well
be an ugly link. Thanks.
--
Bonne route,
Sandy Paris FR

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S O R N I
Archived post

12 May 2004, 17:16 UTC #5

SMMB said:
" S o r n i" <[email hidden]> a écrit dans le
message de :
"]news:[email hidden]...
Quoted message said:
SMMB said:
Just got back in from a nice ride, with a new "problem".
The big ring rubs the front derailleur. Kind of normal,
but with a twist. This only happens every SECOND
revolution. {snip}
Quoted message said:
Quoted message said:
My guess: it's the chain's quick-link connection. (My PC-
99 is noisier than its Shimano predecessor.)
Bill "if it was the ring then it would do it every
rev" S.

OOOOOHH!! Yeah ! The period is about right, I see ! Just
one thing - no quick link on my C9 chain.... But it could
well be an ugly link. Thanks.
Right. Run the chain between your thumb and forefinger, and
see if there's a protruding rivet (probably where you joined
the chain). Also check for a stiff link, although that would
usually cause a rear derailleur blip more than a front tic.
(Love it when I try to sound techie!)
Bill "need to fire MY mechanic (me)" S.

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A Muzi
Archived post

13 May 2004, 04:20 UTC #6

SMMB said:
Just got back in from a nice ride, with a new "problem".
The big ring rubs the front derailleur. Kind of normal,
but with a twist. This only happens every SECOND
revolution. I first noticed it while in big/little on a 2%
incline, while standing. So, I sat. No change. Not each
revolution, that's the screwy part, each other revolution.

-snip-
That may be a damaged chain link, whose plate passes the
front changer not in sync with pedal rpm.
Sight your chain from one end and pedal a full chain
revolution. I any link is different fromthe others
investigate that asap . Chain failure is serious.
--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971

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