Chatter under braking -- causes?

For a couple of days now I've been noticing a small chatter at the
front wheel under braking.

My first thought was that in retorqueing the stem to steering shaft
bolts I somehow disturbed the headset preload. I took one of those
bolts out and reinserted and tightened it before touching the other
one, so the steerer should never have been loose. There's no rock or
knock in the normal brake-on and push test.

I also retorqued the hex fastener which replaces the QR on the front
axle through the SON hub. But, once more, there's nothing loose there.

Any other cause? Anywhere else I should look?

It's probably good to be sensitive to noise and knock and wobble for a
ride or two after dropping the wheels, but if you guys can't think of
something else I should check, I'll just conclude I'm being hyper-
sensitive.

Andre Jute
I'm not a know-all. I don't need to be. I know who to ask.

Andre Jute wrote:
For a couple of days now I've been noticing a small chatter at the
front wheel under braking.

My first thought was that in retorqueing the stem to steering shaft
bolts I somehow disturbed the headset preload. I took one of those
bolts out and reinserted and tightened it before touching the other
one, so the steerer should never have been loose. There's no rock or
knock in the normal brake-on and push test.

I also retorqued the hex fastener which replaces the QR on the front
axle through the SON hub. But, once more, there's nothing loose there.

Any other cause? Anywhere else I should look?

It's probably good to be sensitive to noise and knock and wobble for a
ride or two after dropping the wheels, but if you guys can't think of
something else I should check, I'll just conclude I'm being hyper-
sensitive.

Andre Jute
I'm not a know-all. I don't need to be. I know who to ask.

I had a similar issue after attempting to true the wheels on my bike.
I'd put some penetrating oil on the spoke nipples as some of them were
very tight. Apparently I'd got a little on the brake track of the front
wheel. It makes an alarming difference in the coefficient of friction,
to the point where I could see the fork blades physically moving. I'd
like to say a good cleaning fixed it, but I swapped wheels and brake
pads almost immediately afterwards, and that definitely fixed it

Thank you for reminding me that I need to clean those wheels; I just
swapped them back on because I'm using my "good" wheels to set up the
other bike...

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On 09/12/2009 04:41 PM, barbara cartland, the ridiculous impostor bleated:
For a couple of days now I've been noticing a small chatter at the
front wheel under braking.

hey, barbara, just keep your freakin' mouth shut - that'll solve the
problem.

On 13 Sep, 00:41, Andre Jute wrote:
For a couple of days now I've been noticing a small chatter at the
front wheel under braking.

Voices?


My first thought was that in retorqueing the stem to steering shaft
bolts I somehow disturbed the headset preload. I took one of those
bolts out and reinserted and tightened it before touching the other
one, so the steerer should never have been loose. There's no rock or
knock in the normal brake-on and push test.

I also retorqued the hex fastener which replaces the QR on the front
axle through the SON hub. But, once more, there's nothing loose there.

I think that the relevant authority will find you have a screw loose.


Any other cause? Anywhere else I should look?

Asylum.


It's probably good to be sensitive to noise and knock and wobble for a
ride or two after dropping the wheels, but if you guys can't think of
something else I should check, I'll just conclude I'm being hyper-
sensitive.

That's one way of putting it.

On Sep 13, 12:55*am, Nate Nagel wrote:
Andre Jute wrote:
For a couple of days now I've been noticing a small chatter at the
front wheel under braking.

My first thought was that in retorqueing the stem to steering shaft
bolts I somehow disturbed the headset preload. I took one of those
bolts out and reinserted and tightened it before touching the other
one, so the steerer should never have been loose. There's no rock or
knock in the normal brake-on and push test.

I also retorqued the hex fastener which replaces the QR on the front
axle through the SON hub. But, once more, there's nothing loose there.

Any other cause? Anywhere else I should look?

It's probably good to be sensitive to noise and knock and wobble for a
ride or two after dropping the wheels, but if you guys can't think of
something else I should check, I'll just conclude I'm being hyper-
sensitive.

Andre Jute
I'm not a know-all. I don't need to be. I know who to ask.

I had a similar issue after attempting to true the wheels on my bike.
I'd put some penetrating oil on the spoke nipples as some of them were
very tight. *Apparently I'd got a little on the brake track of the front
wheel. *It makes an alarming difference in the coefficient of friction,
to the point where I could see the fork blades physically moving. *I'd
like to say a good cleaning fixed it, but I swapped wheels and brake
pads almost immediately afterwards, and that definitely fixed it

Thank you for reminding me that I need to clean those wheels; I just
swapped them back on because I'm using my "good" wheels to set up the
other bike...

nate

--
replace "roosters" with "cox" to reply.http://members.cox.net/njnagel

This is good stuff, Nate. I put enough oil on the chain to give it
enough of a soaking for a couple of desert spoons to drip out of the
Country chaincase (nearest thing on the market to actually being that
mythical oil bath) over the next few days. I didn't think any of that
oil got on the rims, but the rims surely gave off an inordinate amount
of oil onto the cloth when I wiped them. (I live in the country and
ride on pretty clean lanes with, by American and British standards,
light traffic, so my rims should be generally clean or at worse have
cow dung on them, not oil, not even mud.) I'll check whether there is
oil on just one of the brake pads.

Also, I know stuff around the front wheel got disturbed because I had
to reset the sensors for the speedo/bike computer and also the spoke
reflectors which were clicking against the sensors. I'll also check
that the wheel is back in perfectly straight, though I think a skew
wheel won't wait until you're braking hard to start complaining.
Still, with those very fat tyres (60mm) it is tricky to say when the
wheel is in straight -- actually, with the narrow space around it
inside the fork, I originally thought it would be easier to put in
straight than a skinny tyre.

Andre Jute
Visit Andre's books at
http://www.audio-talk.co.uk/fiultra/THE%20WRITER'S%20HOUSE.html

On Sat, 12 Sep 2009 16:41:21 -0700 (PDT), Andre Jute
wrote:

For a couple of days now I've been noticing a small chatter at the
front wheel under braking.

Some roughness or irregularity of the rim and/or flexy brake calipers.

Thanks to all who helped and particularly to Nate. On hand of the
suggestions I investigated various other causes. The actual cause of
the chatter under braking was that when I removed and replaced the
wheel for retorqueing the axle nut, I put it back asymmetrically with
regard to the brake block-to-rim spacing, and possibly marginally skew
as well, as differential brake block distances shouldn't make any
difference to a hydraulically actuated system like the Magure rim
brakes. Anyhow, I removed the wheel, fitted it back carefully, checked
it for symmetry to all surfaces, and torqued everything up again. Took
a ride down the Grammar School Hill and hit the brakes hard from over
50kph. Braked down smooth as a baby's bot.

While I was checking the other suggestions, I found a terrifying
amount of black oily stuff on the brake block friction surfaces and a
thorough cleaning of the rims revealled yet more oily black stuff than
I picked up in the cursory wipe the other day. Dunno where it comes
from -- i don't ride behind diesel trucks that often -- but you don't
have to be a genius to know it can't enhance the stopping power of the
brakes.

Andre Jute
"The first American car was sold to an American on April Fool's Day,
1898." -- Ralph Stein in "Vintage and Classic Cars", Bantam Books,
1977


On Sep 13, 12:41*am, Andre Jute wrote:
For a couple of days now I've been noticing a small chatter at the
front wheel under braking.

My first thought was that in retorqueing the stem to steering shaft
bolts I somehow disturbed the headset preload. I took one of those
bolts out and reinserted and tightened it before touching the other
one, so the steerer should never have been loose. There's no rock or
knock in the normal brake-on and push test.

I also retorqued the hex fastener which replaces the QR on the front
axle through the SON hub. But, once more, there's nothing loose there.

Any other cause? Anywhere else I should look?

It's probably good to be sensitive to noise and knock and wobble for a
ride or two after dropping the wheels, but if you guys can't think of
something else I should check, I'll just conclude I'm being hyper-
sensitive.

Andre Jute
I'm not a know-all. I don't need to be. I know who to ask.