clunking sound from crank

Quoted message said:

I just cleaned the chain on my three-month old hybrid and it's
developed an slight intermittent clunking sound (just once every 10 or
15 minutes) that seems to be be coming from the crank, as if the chain
is slightly catching on something or shifting. Happens in every gear
combination. I've had the gears checked out and they're fine. No
stiff links on the chain either. Anyone know what it might be?
Max

could it be the front derralieur rubbing against the chain?
carlos
www.bikingthings.com

Quoted message said:

I just cleaned the chain on my three-month old hybrid and it's
developed an slight intermittent clunking sound (just once every 10 or
15 minutes) that seems to be be coming from the crank, as if the chain
is slightly catching on something or shifting. Happens in every gear
combination. I've had the gears checked out and they're fine. No
stiff links on the chain either. Anyone know what it might be?
Max

If it really comes only that often, it could be a pawl (ratchet) in the
freewheel mechanism that isn't catching once in a while. Take the rear wheel
off, and see if you can feel much sideways slop in the gears. Also rotate it
backward (the only way it will go) and see how it feels. They'll always feel
a bit grindy, so you might have to compare it to another if you're not
familiar with them.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

may have said:

I just cleaned the chain on my three-month old hybrid and it's
developed an slight intermittent clunking sound (just once every 10 or
15 minutes) that seems to be be coming from the crank, as if the chain
is slightly catching on something or shifting. Happens in every gear
combination. I've had the gears checked out and they're fine. No
stiff links on the chain either. Anyone know what it might be?

Is this just a noise, or do you feel it in your feet? The latter
bespeaks a chain trying to climb a tooth for some reason, but if it
happens in every gear then it's not necessarily in the chain area at
all. If it is just a noise, it can have many possible causes, some of
which are fairly trivial.

In addition to other suggestions, check the bolts that hold the cranks
on to the bottom bracket, and check to make sure the kickstand (if you
have one) isn't close enough to be clicking on the left crank once in
a while.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Werehatrack said:

On Wed, 28 Nov 2007 03:27:30 -0800 (PST), [email hidden] may have said:

Quoted message said:

Is this just a noise, or do you feel it in your feet?

I can feel it in my feet as well. It does feel as if it might be a
link in the chain not fitting with a tooth propoerly occasionally but
it's only 3 months old so I don't imagine chain stretch can be a
problem and there isn't an obvious problem with any teeth in the
crank.

may have said:

Werehatrack said:

On Wed, 28 Nov 2007 03:27:30 -0800 (PST), [email hidden] may have said:

Quoted message said:

Is this just a noise, or do you feel it in your feet?

I can feel it in my feet as well. It does feel as if it might be a
link in the chain not fitting with a tooth propoerly occasionally but
it's only 3 months old so I don't imagine chain stretch can be a
problem and there isn't an obvious problem with any teeth in the
crank.

If it always occurs at the same relative foot position and only in one
of the front sprockets, a slightly bent tooth is a possibility, as is
a slight misadjustment of the derailleur if it occurs in more than one
place but never when using the big ring; if the der is just a trifle
too far to the right, a pin on the next sprocket could be trying to
lever the chain up a bit. Also, a single chain link or sideplate
might be bent; this can be a pain in the neck to spot.

I still would check the crank bolts; if loose, this needs to be
corrected right away.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Quoted message said:

Werehatrack said:

On Wed, 28 Nov 2007 03:27:30 -0800 (PST), [email hidden] may have said:

Quoted message said:

Is this just a noise, or do you feel it in your feet?

I can feel it in my feet as well. It does feel as if it might be a
link in the chain not fitting with a tooth propoerly occasionally but
it's only 3 months old so I don't imagine chain stretch can be a
problem and there isn't an obvious problem with any teeth in the
crank.

"It's" only 3 months old? What it, the chain? Is the cassette older?
Chain skip usually happens with a new chain, not an old one. A new
chain used with a worn cassette. Or, maybe worn chainrings (less likely).

It could also be the bottom bracket, but the only-occasional nature of
it seems more like a chain skip.

Does it more often happen when climbing? That would also indicate chain
skip, which happens more under heavier load.

--

David L. Johnson

"What am I on? I'm on my bike, six hours a day, busting my ass.
What are you on?"
--Lance Armstrong

On Wed, 28 Nov 2007 20:52:20 -0500, "David L. Johnson"

may have said:

Quoted message said:

Werehatrack said:

On Wed, 28 Nov 2007 03:27:30 -0800 (PST), [email hidden] may have said:

Quoted message said:

Is this just a noise, or do you feel it in your feet?

I can feel it in my feet as well. It does feel as if it might be a
link in the chain not fitting with a tooth propoerly occasionally but
it's only 3 months old so I don't imagine chain stretch can be a
problem and there isn't an obvious problem with any teeth in the
crank.

"It's" only 3 months old? What it, the chain? Is the cassette older?
Chain skip usually happens with a new chain, not an old one. A new
chain used with a worn cassette. Or, maybe worn chainrings (less likely).

It could also be the bottom bracket, but the only-occasional nature of
it seems more like a chain skip.

Does it more often happen when climbing? That would also indicate chain
skip, which happens more under heavier load.

IIRC, the OP said the whole bike is 3 months old...and the problem is
one of those maddeningly intermittent ones that drive a bike shop
nuts.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Werehatrack said:

IIRC, the OP said the whole bike is 3 months old...and the problem is
one of those maddeningly intermittent ones that drive a bike shop
nuts.

Ah, I did miss that. Unless this hybrid has been ridden more than would
be believable, then, yeah, it probably isn't a worn-out cassette -- nor
is it the chain.

--

David L. Johnson

And though I have the gift of prophecy, and understand all mysteries,
and all knowledge; and though I have all faith, so that I could remove
mountains, and have not charity, I am nothing. [1 Corinth. 13:2]

Werehatrack said:

IIRC, the OP said the whole bike is 3 months old...and the problem is
one of those maddeningly intermittent ones that drive a bike shop
nuts.

On a new-ish bike, I'd double-check the pedals to make sure they were
tightened properly.

Jeff

Quoted message said:

I just cleaned the chain on my three-month old hybrid and it's
developed an slight intermittent clunking sound (just once every 10 or
15 minutes) that seems to be be coming from the crank, as if the chain
is slightly catching on something or shifting. Happens in every gear
combination. I've had the gears checked out and they're fine. No
stiff links on the chain either. Anyone know what it might be?
Max

Just to get the stupid question out of the way, you wouldn't happen to
have a kickstand or a chain guard on the bike would you? Or anything
else that's near the crank during it's rotation?

/s

Quoted message said:

Just to get the stupid question out of the way, you wouldn't happen to
have a kickstand or a chain guard on the bike would you? Or anything
else that's near the crank during it's rotation?

/s

No, no kickstand (and whole bike is 3 months old). I'm sure it's not
something rubbing. It's a clunk or a pop, like something either
slipping or catching, and definitely feels like it's happening around
the crank. It seems to happen more in lower gears when I'm not putting
much load on the pedals, and happens more when going round corners
more than when going straight (although does happen on the straight
too). Doesn't happen at the same point on the pedal revolution either.
Max

Quoted message said:

Quoted message said:

On Wed, 28 Nov 2007 03:27:30 -0800 (PST), [email hidden] may have said:

Is this just a noise, or do you feel it in your feet?

I can feel it in my feet as well. It does feel as if it might be a
link in the chain not fitting with a tooth propoerly occasionally but
it's only 3 months old so I don't imagine chain stretch can be a
problem and there isn't an obvious problem with any teeth in the
crank.

Could be a bad BB bearing. Pull off the crank arms and see if the
spindle spins smoothly.

--

John ([email hidden])

Quoted message said:

Quoted message said:

Just to get the stupid question out of the way, you wouldn't happen to
have a kickstand or a chain guard on the bike would you? Or anything
else that's near the crank during it's rotation?

/s

No, no kickstand (and whole bike is 3 months old). I'm sure it's not
something rubbing. It's a clunk or a pop, like something either
slipping or catching, and definitely feels like it's happening around
the crank. It seems to happen more in lower gears when I'm not putting
much load on the pedals, and happens more when going round corners
more than when going straight (although does happen on the straight
too). Doesn't happen at the same point on the pedal revolution either.
Max

I know that this sounds stupid since the bike is only 3 months old, but
the first thing I thought of when I read the original post was a BB
bearing or loose race or maybe a small adjustment to the locknut or
something like that. Then people started speculating about the chain,
chainring etc. and I thought my idea was too stupid.

But you keep saying it feels like the crank, so I think maybe it is
worth me piping up. A tiny flatspot or difference in size of a bearing
ball could cause this, I think since it only would happen in a
particular circumstance. It would be a very cheap fix to replace the
bearings and see if it improves.

Quoted message said:

Quoted message said:

Quoted message said:

[email hidden] may have said:
Is this just a noise, or do you feel it in your feet?

Quoted message said:

Quoted message said:

I can feel it in my feet as well. It does feel as if it might be a
link in the chain not fitting with a tooth propoerly occasionally but
it's only 3 months old so I don't imagine chain stretch can be a
problem and there isn't an obvious problem with any teeth in the
crank.

John Thompson said:

Could be a bad BB bearing. Pull off the crank arms and see if the
spindle spins smoothly.

Good point.
Just because it's 'new' doesn't mean it's 'right':

http://www.yellowjersey.org/photosfromthepast/DREKINBB.JPG
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

vey said:

Quoted message said:

Quoted message said:

Just to get the stupid question out of the way, you wouldn't happen to
have a kickstand or a chain guard on the bike would you? Or anything
else that's near the crank during it's rotation?

Quoted message said:

Quoted message said:

/s

Quoted message said:

No, no kickstand (and whole bike is 3 months old). I'm sure it's not
something rubbing. It's a clunk or a pop, like something either
slipping or catching, and definitely feels like it's happening around
the crank. It seems to happen more in lower gears when I'm not putting
much load on the pedals, and happens more when going round corners
more than when going straight (although does happen on the straight
too). Doesn't happen at the same point on the pedal revolution either.
Max

I know that this sounds stupid since the bike is only 3 months old, but
the first thing I thought of when I read the original post was a BB
bearing or loose race or maybe a small adjustment to the locknut or
something like that. Then people started speculating about the chain,
chainring etc. and I thought my idea was too stupid.

But you keep saying it feels like the crank, so I think maybe it is
worth me piping up. A tiny flatspot or difference in size of a bearing
ball could cause this, I think since it only would happen in a
particular circumstance. It would be a very cheap fix to replace the
bearings and see if it improves.

How frustrating. It sure _sounds_ like a stiff link....

It's interesting that you're getting this in medium/light gears under
little load. Do you have any spare parts that you know to be smooth
and reliable? Like pedals, for instance, that you can temporarily
replace and see if that quiets things down?

If it's under light load, are you seated in these turns? Maybe check
the seat rails, or remove the seat post, grease up the seat tube, and
reinsert? Do you have enough seat post in the frame?

I know this sounds like I'm dancing around the perceived problem area,
but a lot of mystery sounds that seem to emanate from the bb area are
from elsewhere on the bike.

/s

Quoted message said:

I just cleaned the chain on my three-month old hybrid and it's
developed an slight intermittent clunking sound (just once every 10 or
15 minutes) that seems to be be coming from the crank, as if the chain
is slightly catching on something or shifting. Happens in every gear
combination. I've had the gears checked out and they're fine. No
stiff links on the chain either. Anyone know what it might be?
Max

A once-per-revolution clunking can be really difficult to find. As
I've related here more than once, I chased one of these for a few
weeks without success. Then while just riding along my saddle suddenly
tipped back. After readjusting and tightening the saddle rail clamp
the clunking had magically gone away.

I'm not saying this is your problem, just saying this is what happened
to me.

--
jeverett3<AT>sbcglobal<DOT>net (John V. Everett)