A Puzzling 'Clack!'

steve-<< Once in a while (like maybe once every 20 miles over varied terrain) there is a kind of
'clack!' noise from my ride crank area. It is the kind of sound that the crank might make if it hit
a kickstand that stuck out a tiny bit, but I have no kickstand. >><BR><BR>

Freehub?

Take off and clean and OIL...??

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali costruite eccezionalmente bene"

"Steve Juniper" <[email hidden]> wrote in message news:euC%a.163178$uu5.25061@sccrnsc04...

Quoted message said:

Once in a while (like maybe once every 20 miles over varied terrain)
there is a kind of 'clack!' noise from my ride crank area. It is the kind

of

Quoted message said:

sound that the crank might make if it hit a kickstand that stuck out a

tiny

Quoted message said:

bit, but I have no kickstand. It seems to do it most likely when changing from easy pedaling to
harder pedaling, or maybe after coasting a bit, but not always. Crank is tight. Pedals spin
smoothly. It is hard to tell just when it happens in the rotation, as it is

always

Quoted message said:

so unexpected, but maybe swinging over the top. Been happening for well

over

Quoted message said:

a year and probably 2-3 thousand miles, so it's most likely nothing

urgent.

Quoted message said:

Two bike shops with good reputations have found nothing the matter. I rode it the length of the
Pyrenees last summer with not problem, so at this

point

Quoted message said:

I'm more curious than worried. Any ideas?
--

What pedals are you using? How old are your cleats?

--
Robin Hubert <[email hidden]

Steve Juniper said:

Once in a while (like maybe once every 20 miles over varied terrain) there is a kind of 'clack!'
noise from my ride crank area. It is the kind of sound that the crank might make if it hit a
kickstand that stuck out a tiny bit, but I have no kickstand. It seems to do it most likely when
changing from easy pedaling to harder pedaling, or maybe after coasting a bit, but not always.
Crank is tight. Pedals spin smoothly.

The sound, other than it's infrequency, is commonly made by the BB bearing when the ball cage starts
disintegrating, one tab at a time. When these parts get between the ball and race they emit a solid
'clack'. Open the BB and clean and grease the bearing. If its a cartridge bearing BB, put in a new
pair of bearings.

Jobst Brandt [email hidden] Palo Alto CA

Shimano SPD Sport one-sided pedals. They rotate very smoothly and I think that if the noise was
coming from the clats or I'd feel it in my feet.
--
Steve

Steve Juniper ([email hidden]) Berkeley, California "Every day above ground is a
good day!"

"Robin Hubert" <[email hidden]> wrote in message
"]news:[email hidden]... "Steve Juniper"
<[email hidden]> wrote in message news:euC%a.163178$uu5.25061@sccrnsc04...

Quoted message said:

Once in a while (like maybe once every 20 miles over varied terrain)
there is a kind of 'clack!' noise from my ride crank area. It is the kind

of

Quoted message said:

sound that the crank might make if it hit a kickstand that stuck out a

tiny

Quoted message said:

bit, but I have no kickstand. It seems to do it most likely when changing from easy pedaling to
harder pedaling, or maybe after coasting a bit, but not always. Crank is tight. Pedals spin
smoothly. It is hard to tell just when it happens in the rotation, as it is

always

Quoted message said:

so unexpected, but maybe swinging over the top. Been happening for well

over

Quoted message said:

a year and probably 2-3 thousand miles, so it's most likely nothing

urgent.

Quoted message said:

Two bike shops with good reputations have found nothing the matter. I rode it the length of the
Pyrenees last summer with not problem, so at this

point

Quoted message said:

I'm more curious than worried. Any ideas?
--

What pedals are you using? How old are your cleats?

--
Robin Hubert <[email hidden]

Steve Juniper said:

It is hard to tell just when it happens in the rotation, as it is always so unexpected, but maybe
swinging over the top. Been happening for well over a year and probably 2-3 thousand miles, so it's
most likely nothing urgent. Two bike shops with good reputations have found nothing the matter. I
rode it the length of the Pyrenees last summer with not problem, so at this point I'm more curious
than worried. Any ideas?
--

Look at the inside of your right crankarm for a line scratch. It may be that your front derailleur
is hitting the crankarm when it is fully extended. You may need to adjust the stop or get a
different front derailleur. It happens to me when I use a MTB front derailleur on road crankset.

Steve Juniper said:

Once in a while (like maybe once every 20 miles over varied terrain) there is a kind of 'clack!'
noise from my ride crank area. It is the kind of sound that the crank might make if it hit a
kickstand that stuck out a tiny bit, but I have no kickstand. It seems to do it most likely when
changing from easy pedaling to harder pedaling, or maybe after coasting a bit, but not always.

Quoted message said:

It is hard to tell just when it happens in the rotation, as it is always so unexpected, but maybe
swinging over the top.

I've had a very similar symptom on two bikes - an occasional 'clack', most commonly when applying
pressure after coasting. As you say, it's so occasional that it's hard to trace, but it seems more
common at the extremes of the cassette than in the middle.

The first setup that produced this effect was a TA 48t 9-speed chainring, SRAM PC59 chain, Ultegra
12-27 cassette on a '98 XT freehub. The second was a 44t Middleburn chainring, PC59 chain, Ultegra
11-23 cassette and '01 Ultegra hub. These are the larger rings of each setup, and I haven't noticed
the problem in other combinations.

At first I suspected that the freehub pawls might be mis-engaging momentarily, causing the drive to
slip, sending a wave through the chain that manifested itself as a noise at the chainring, but when
I happened to use the second hub and chain with a different chainring (a tall-toothed round 'Egg'
ring from Highpath Engineering, designed for use as a single chainring) the problem went away.

My hunch is that the slack chain may be partially derailing from the chainring, then popping back
into engagement when pressure is applied, maybe due to a combination of tooth profile and chain
design. I've wondered whether it might have something to do with the position of the SRAM 'Power
link' when pressure is first applied - that might explain why the noise is so intermittent.

Is any of that helpful?

James Thomson

Quoted post said:

Originally posted by Steve Juniper
Once in a while (like maybe once every 20 miles over varied terrain) there is a kind of 'clack!'
noise from my ride crank area.

Could be that the bottom bracket on your frame was never properly faced. This would be an issue with a new frame with a traditional cups-and-axle bb. Before mounting, the threads should be milled out and the facings milled square. Otherwise, when you crank down on the lock ring, the torque on the cup can actually cause the bb on the frame to distort.

Often, a frame manufacturer will expect the shop builder to do the facing. Also, some hastily built factory bikes aren't faced. A reputable shop with the proper tools can do this.

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

Quoted message said:

Steve Juniper said:

Once in a while (like maybe once every 20 miles over varied terrain) there is a kind of
'clack!' noise from my ride crank area.

I had a similar problem very recently and the "clarking" sound became a lot worse and more
frequent. I took the bottom bracket out. It was a cheap cartridge bottom bracket constructed with a
plastic sleeve. The plastic sleeve had disengaged slighty on the right hand drive side. It would
have been possibe to press the sleeve back in place but I just decided to replace the BB with a
better quality one.

-R