loud grinding noise

During the past few months my racing bike (1999, Bianchi with Campagnolo Mirage, twelve thousand
miles) has been intermittently making a loud grinding noise, like two pieces of metal rubbing over
each other. It typically happens when I start to pedal lightly again after coasting. It doesn't last
for more than a second. It feels as if something that came loose is tightened by the pedalling.
Sometimes it occurs a few times in a ride, sometimes it's absent for days. It comes from somewhere
below, between the bottom bracket and the rear derailer. I can't localise it more precisely and
can't induce it on a workstand. Recently, there has been a second, softer noise that doesn't go away
immediately and which I can feel through my saddle. This seems to be accompanied by a slight drag,
although I'm not a hundred percent certain of this.

My LBS checked it and found nothing. I'd appreciate your advice.

Mark Runacres Brussels, Belgium

 

"Mark Runacres" <[email protected]> wrote in message
news:[email protected]...
> During the past few months my racing bike (1999, Bianchi with Campagnolo Mirage, twelve thousand
> miles) has been intermittently making a loud
grinding
> noise, like two pieces of metal rubbing over each other. It typically
happens
> when I start to pedal lightly again after coasting. It doesn't last for
more
> than a second. It feels as if something that came loose is tightened by
the
> pedalling. Sometimes it occurs a few times in a ride, sometimes it's
absent
> for days. It comes from somewhere below, between the bottom bracket and
the
> rear derailer. I can't localise it more precisely and can't induce it on a workstand. Recently,
> there has been a second, softer noise that doesn't go away
immediately
> and which I can feel through my saddle. This seems to be accompanied by a slight drag, although
> I'm not a hundred percent certain of this.
>
> My LBS checked it and found nothing. I'd appreciate your advice.

Remove the cranks. Spin the BB in your fingers to evaluate the bearing. Check to see it is tight in
the frame. Lubricate crank bolts, under the heads and torque properly ( either wet the spindle or
not according to your religion). Remove chainringboolts and grease the male side before retorquing.

Remove the rear wheel. Turn the axle in your fingers to evaluate the bearing. Ensure the cassette
lockring is lubed and snug ( needn't be overly tight). Flex all the spokes with your hands, ensuring
there isn't one dangling or broken. Remove the pedals, spin the spindle inyour fingers to evaluate
the bearing. Grease and retorque.

All that should take about twenty minutes or less and will either remove your noise or explain it.
And you'll be ready for a new season with greater confidence that your bike's lower end is all well.

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

 

On Tue, 14 Jan 2003 11:44:06 -0500, Mark Runacres wrote:

> During the past few months my racing bike (1999, Bianchi with Campagnolo Mirage, twelve thousand
> miles) has been intermittently making a loud grinding noise, like two pieces of metal rubbing over
> each other. It typically happens when I start to pedal lightly again after coasting. It doesn't
> last for more than a second. It feels as if something that came loose is tightened by the
> pedalling. Sometimes it occurs a few times in a ride, sometimes it's absent for days. It comes
> from somewhere below, between the bottom bracket and the rear derailer. I can't localise it more
> precisely and can't induce it on a workstand. Recently, there has been a second, softer noise that
> doesn't go away immediately and which I can feel through my saddle. This seems to be accompanied
> by a slight drag, although I'm not a hundred percent certain of this.
>
> My LBS checked it and found nothing. I'd appreciate your advice.

Just a guess: Is there any side-to-side play in the rear wheel? If so, it could be rubbing on a
brake pad or maybe a chainstay. I once found a friend's bike to have 3-4mm of play that he didn't
notice. His wheel (Rolf) was toast.

But if your LBS wrench is competent he would look for that.

--

David L. Johnson

__o | Enron's slogan: Respect, Communication, Integrity, and _`\(,_ | Excellence. (_)/ (_) |

 

Mark Runacres wrote:
> During the past few months my racing bike (1999, Bianchi with Campagnolo Mirage, twelve thousand
> miles) has been intermittently making a loud grinding noise, like two pieces of metal rubbing over
> each other. It typically happens when I start to pedal lightly again after coasting. It doesn't
> last for more than a second. It feels as if something that came loose is tightened by the
> pedalling. Sometimes it occurs a few times in a ride, sometimes it's absent for days. It comes
> from somewhere below, between the bottom bracket and the rear derailer. I can't localise it more
> precisely and can't induce it on a workstand. Recently, there has been a second, softer noise that
> doesn't go away immediately and which I can feel through my saddle. This seems to be accompanied
> by a slight drag, although I'm not a hundred percent certain of this.
>
> My LBS checked it and found nothing. I'd appreciate your advice.
>
> Mark Runacres Brussels, Belgium
From your descrption I would guess that your BB is disintegrating. What you described is exactly
what I experienced. The grinding noise I heard was the baring balls getting ground up by other BB
bits. I take it you never checked your BB after rides in the rain for water contamination. If water
has a chance to build up in the BB shell over time this will kill your BB.

Kenny Lee

 

replace ur bottom bracket.

"David L. Johnson >" <David L. Johnson <[email protected]> wrote in message
news:[email protected]...
> On Tue, 14 Jan 2003 11:44:06 -0500, Mark Runacres wrote:
>
> > During the past few months my racing bike (1999, Bianchi with Campagnolo Mirage, twelve thousand
> > miles) has been intermittently making a loud grinding noise, like two pieces of metal rubbing
> > over each other. It typically happens when I start to pedal lightly again after coasting. It
> > doesn't last for more than a second. It feels as if something that came loose is tightened by
> > the pedalling. Sometimes it occurs a few times in a ride, sometimes it's absent for days. It
> > comes from somewhere below, between the bottom bracket and the rear derailer. I can't localise
> > it more precisely and can't induce it on a workstand. Recently, there has been a second, softer
> > noise that doesn't go away immediately and which I can feel through my saddle. This seems to be
> > accompanied by a slight drag, although I'm not a hundred percent certain of this.
> >
> > My LBS checked it and found nothing. I'd appreciate your advice.
>
> Just a guess: Is there any side-to-side play in the rear wheel? If so, it could be rubbing on a
> brake pad or maybe a chainstay. I once found a friend's bike to have 3-4mm of play that he didn't
> notice. His wheel (Rolf) was toast.
>
> But if your LBS wrench is competent he would look for that.
>
> --
>
> David L. Johnson
>
> __o | Enron's slogan: Respect, Communication, Integrity, and _`\(,_ | Excellence. (_)/ (_) |