squeaking BB

On Oct 17, 10:04*pm, wrote:
Peter Chisholm wrote:
Recently, my Shimano 7700 BB developed squeaking noise when I
stop pedaling when cruising? *Anybody knows why? *It has about
20000km on it now.
Not sure how it can 'squeak' when you aren't pedaling. *BUT take
it all apart, clean, lube well including the spindle. *These are
kinda noisy.
Maybe there's a mouse in it running like crazy?
Can you lube sealed units?
Not actually putting any grease into the bearings them selves but
you need grease between the cups and frame (Prep that frame!), onto
the spindle, between the rings and the crank spider, onto the
chainring bolts. *Torque wrench required also.

If it is squeaking, and it is the BB, then you have a serious problem
in that the bearing cup is moving in the frame. *Grease can only
obscure that problem but the motion will not go away. *That would only
be "sweeping i under the rug" so to speak.

Bicycles have been fraught with such design problems since the
beginning. *Pedal attachment, head bearing fretting, quill stems
failing, pedal cranks designed as "in plane" levers ignoring their
torsion and lateral bending, rear hub axle overhang on the right side
causing chain tension to break axles and dropouts, Cinelli internally
lugged fork crowns whose transition to fork blades could not be
feathered, thus causing fork fatigue failures...

Now we have the outboard BB bearings that wants to fret more than
ever. *The old inboard ones did which the need for a left hand thread
on the right cup demonstrates.

Jobst Brandt


The squeaking noise is like "Gua.. gua..",

The BB is not squeaking all the time, I am commuting by bicycle. The
length of crank arm is 170mm.
Yesterday(Thursday), I pumped tire pressure to 110/120psi. No noise at
all.
Wednesday(the day before), squeaking if stop pedalling, the tire
pressure was about 80/90psi.(pumped one week ago)
is there something related to this, am I ridiculous when I connect
the squeaking to tire pressure?

"Felix qui potuit rerum cognoscere causas." - Virgil

On Thu, 16 Oct 2008 19:07:48 -0500, "Carl Sundquist"
wrote:


"John Dacey" wrote in message
.. .
" Est et fideli tuta silentio merces." - Horace

On Wed, 15 Oct 2008 20:27:01 -0700 (PDT), goodone
wrote:

Recently, my shimano 7700 BB developed squeaking noise when I stop
pedalling when cruising? Anybody knows why?

A bottom bracket that isn't moving shouldn't make a sound. Check to
see that it isn't your saddle. Try introducing a few drops of oil at
each place where the rails insert into the saddle's shell.

He didn't say, but if he stops pedaling at TDC/BDC and puts all his weight
on the lower pedal, he could be getting some creaking from the axle/crankarm
interface.

Yes, but I think that in the situation you cite, the creak/squeak
would'nt be persistent unless the rider continually fidgets how much
body weight is borne on the pedal.

The real point I was trying to make is that misattribution of the
source of the problem has reasonable likelihood in the instant case
and that addressing the bottom bracket alone may not solve the issue.
Saddle rail squeaking; chirping derailleur pulley bushings; shoe
cleats creaking; spoke nipples squeaking against their rim beds;
squealing freehub body bushings; handlebar & stem groans and a number
of other conditions occasionally prove to be the actual cause of
complaints that "my bottom bracket is making a noise".

Of course, after 20,000k of service, it wouldn't be premature to have
the OP service his 7700 bottom bracket either.
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Since 1983 (25th Year!)
Comprehensive catalogue of track equipment: online since 1996
http://www.businesscycles.com
-------------------------------

On Oct 17, 10:06*am, goodone wrote:
On Oct 17, 10:04*pm, wrote:





Peter Chisholm wrote:
Recently, my Shimano 7700 BB developed squeaking noise when I
stop pedaling when cruising? *Anybody knows why? *It has about
20000km on it now.
Not sure how it can 'squeak' when you aren't pedaling. *BUT take
it all apart, clean, lube well including the spindle. *These are
kinda noisy.
Maybe there's a mouse in it running like crazy?
Can you lube sealed units?
Not actually putting any grease into the bearings them selves but
you need grease between the cups and frame (Prep that frame!), onto
the spindle, between the rings and the crank spider, onto the
chainring bolts. *Torque wrench required also.

If it is squeaking, and it is the BB, then you have a serious problem
in that the bearing cup is moving in the frame. *Grease can only
obscure that problem but the motion will not go away. *That would only
be "sweeping i under the rug" so to speak.

Bicycles have been fraught with such design problems since the
beginning. *Pedal attachment, head bearing fretting, quill stems
failing, pedal cranks designed as "in plane" levers ignoring their
torsion and lateral bending, rear hub axle overhang on the right side
causing chain tension to break axles and dropouts, Cinelli internally
lugged fork crowns whose transition to fork blades could not be
feathered, thus causing fork fatigue failures...

Now we have the outboard BB bearings that wants to fret more than
ever. *The old inboard ones did which the need for a left hand thread
on the right cup demonstrates.

Jobst Brandt

The squeaking noise is like "Gua.. gua..",

The BB is not squeaking all the time, I am commuting by bicycle. The
length of crank arm is 170mm.
Yesterday(Thursday), I pumped tire pressure to 110/120psi. No noise at
all.

How sure are you that the noise is coming from the bottom bracket?
It's easy for noises to travel through the bike frame and make it hard
to correctly identify the source.

Is the 'gua ... gua ..." sound happening at about the same frequency
as the wheel rotation? If so, I'd suspect some part associated with
the wheel. Loose spokes can make that kind of periodic squeak and
could be influenced by the lack of torque when coasting as well as the
tire pressure (although that's less common). I'd also check to see if
anything might be rubbing on the freehub/cassette area so it makes a
noise only while coasting.