Newbie help with bike noise

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Feronni said:

I've recently decided to get back into cycling and have
bought a mountain bike which I use for normal off road use
(woods, canal tracks). I've done about 70 miles in the
first three weeks and can take it into the place I boughty
it from for a free check up and general tighten up.

I've noticed a certain noise when cycling which I was
wondering if anyone can advise me on its origin before I
take it back for its check over.

When cycling slowly I have become aware of a knocking kind
of noise that seems to vibrate through the pedals, this
seems to happen once every revolution of the pedals. I can
still detect it at faster speeds too and it seems to
happen regardless of the gear that I am in (gears are
shimano easyfire 21).

Sounds like the bottom bracket is it sealed.. though
this is unlikly if it is sealed shich if new i would
expect it to be.

Peter

Feronni said:

When cycling slowly I have become aware of a knocking kind
of noise that seems to vibrate through the pedals, this
seems to happen once every revolution of the pedals. I can
still detect it at faster speeds too and it seems to
happen regardless of the gear that I am in (gears are
shimano easyfire 21).

If I freewheel and turn pedals slowly whilst riding I
can't detect it and also can not detect it if I raise
backwheel and crank pedals.

Is there any play in the bottom bracket axle (either axially
(sorry) or laterally?)

Alternatively, if it's a unit with ball bearings in a race
(unlikely, now everything seems to be sealed bottom
brackets) it might be one or more of the bearings has
disintegrated (been there, tipped out bits of metal when I
disassembled it) - that manifested itself in a particularly
violent knocking on the crank stroke.

(Of course, if it's a sealed unit it might also be this, but
you wouldn't be able to take it apart and fix it because
it's, well, sealed :-)

R.

"Ricardo" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Is there any play in the bottom bracket axle (either
axially (sorry) or laterally?)

No, that all seems ok.

Cranking the pedals (with the back wheels raised) doesn't
produce the knocking vibration / noise (its like a clonk
every revolution, you can hear it if you listen carefully
and feel the clonk vibrate through the pedals, and it seems
to be on the right pedal downstroke only) - only occurs
when cycling.

Thanks

in message <[email hidden]>, Feronni

(') said:

I've recently decided to get back into cycling and have
bought a mountain bike which I use for normal off road use
(woods, canal tracks). I've done about 70 miles in the
first three weeks and can take it into the place I boughty
it from for a free check up and general tighten up.

I've noticed a certain noise when cycling which I was
wondering if anyone can advise me on its origin before I
take it back for its check over.

When cycling slowly I have become aware of a knocking kind
of noise that seems to vibrate through the pedals, this
seems to happen once every revolution of the pedals. I can
still detect it at faster speeds too and it seems to
happen regardless of the gear that I am in (gears are
shimano easyfire 21).

This is either a pedal bearing or the bottom bracket
bearing. Turn the bike upside down and rotate the pedals
with your hands, putting all your weight on them. Do you
feel the knock on one side only or on both? If on both it's
probably the bottom bracket bearing; if on one only it's
probably a pedal bearing.

These days most bottom brackets are not designed to be
stripped and serviced; many pedals still are. However,
seeing this is a new bike you shouldn't need to fix it
yourself. Instead you need to point the problem out to the
shop when you take it in for its inspection, and make sure
they fix it.

--
[email hidden] (Simon Brooke)
jasmine.org.uk~simonOpen ↗

;; All in all you're just another hick in the mall
-- Drink C'lloid

On Wed, 16 Jun 2004 21:35:02 GMT, Simon Brooke <[email hidden]>

wrote in message : said:

This is either a pedal bearing or the bottom bracket
bearing.

Or a loose / split crank. Tighten the crank bolts first!

Guy
--
May contain traces of irony. Contents liable to settle after posting.
chapmancentral.co.ukchapmancentral.co.ukOpen ↗

88% of helmet statistics are made up, 65% of them at Washington University

Feronni said:

"Ricardo" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Is there any play in the bottom bracket axle (either
axially (sorry) or laterally?)

No, that all seems ok.

Cranking the pedals (with the back wheels raised) doesn't
produce the knocking vibration / noise (its like a clonk
every revolution, you can hear it if you listen carefully
and feel the clonk vibrate through the pedals, and it
seems to be on the right pedal downstroke only) - only
occurs when cycling.

Sounds like a loose crank to me. I take it this is a
cotterless crank (you'll find a pin going through it if
it isn't).

--
Andy Hewitt ** FAF#1, (Ex-OSOS#5) - FJ1200 ABS Honda
Concerto 16v: Windows free zone (Mac G5 Dual Processor)
thehewitts.plus.comthehewitts.plus.comOpen ↗ - now online

In article <[email hidden]>, Feronni

Quoted message said:

Cranking the pedals (with the back wheels raised) doesn't
produce the knocking vibration / noise (its like a clonk
every revolution, you can hear it if you listen carefully
and feel the clonk vibrate through the pedals, and it
seems to be on the right pedal downstroke only) - only
occurs when cycling.

Is the left hand crank touching the frame ?

--
A T (Sandy) Morton on the Bicycle Island In the Global
Village millport.netmillport.netOpen ↗

"Just zis Guy, you know?" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

On Wed, 16 Jun 2004 21:35:02 GMT, Simon Brooke
<[email hidden]> wrote in message <7rp6q1-
[email hidden]>:

Quoted message said:

This is either a pedal bearing or the bottom bracket
bearing.

Or a loose / split crank. Tighten the crank bolts first!

I've also had similar symptoms at points on my : hybrid - it
was a pedal bearing road bike - it was a loose pedal mtb -
it was a loose crank bolt

Make sure the pedals and crank bolts are tight then see if
the problem persists.

Doug

"Ricardo" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Alternatively, if it's a unit with ball bearings in a race
(unlikely, now everything seems to be sealed bottom
brackets) it might be one or more of the bearings has
disintegrated (been there, tipped out bits of metal when I
disassembled it) - that manifested itself in a
particularly violent knocking on the crank stroke.

(Of course, if it's a sealed unit it might also be this,
but you wouldn't be able to take it apart and fix it
because it's, well, sealed

:-)

Quoted message said:

R.

Thanks for all your help and comments.

Took it back to the shop and they reckon its a bottom
bracket that has gone. They've had 3 bikes (same models)
with similar problems that have gone the same way, so they
reckon on it being a batch of faulty shimano sealed units
they have, so they are going to replace it for me.

Thanks