Noisy disk brake

[LSMike]

My front disk brake is sometimes noisy, especially when I have only
light pressure on the handle, or when I'm releasing pressure to come to
a more gentle stop. I've been using the rear brake to feather my
arrival at traffic lights.

Is this normal for a well used hydraulic disk brake? Ideally I'd like
to eliminate the noise and have the quiet of the brakes on the new
Hurricane I test rode.

Now that I've ridden the bike for almost two weeks and put 200 miles on
her, the brake is much quieter already, but it could still be improved
I feel. No doubt the bike hadn't been used very much in the last 6
months by the previous owner, he had bought himself a brand new Seiran
Superlight high racer (apparently about 10kg!!).

 

[Simon Brooke]

in message <[email protected]>,
LSMike ('[email protected]') wrote:

> My front disk brake is sometimes noisy, especially when I have only
> light pressure on the handle, or when I'm releasing pressure to come
> to
> a more gentle stop. I've been using the rear brake to feather my
> arrival at traffic lights.
>
> Is this normal for a well used hydraulic disk brake? Ideally I'd like
> to eliminate the noise and have the quiet of the brakes on the new
> Hurricane I test rode.

Clean the disk with meths.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

-- mens vacua in medio vacuo --

 

[Shaun Murray]

In article <[email protected]>,
"LSMike" <[email protected]> wrote:

> My front disk brake is sometimes noisy, especially when I have only
> light pressure on the handle, or when I'm releasing pressure to come to
> a more gentle stop. I've been using the rear brake to feather my
> arrival at traffic lights.
>
> Is this normal for a well used hydraulic disk brake? Ideally I'd like
> to eliminate the noise and have the quiet of the brakes on the new
> Hurricane I test rode.
>
> Now that I've ridden the bike for almost two weeks and put 200 miles on
> her, the brake is much quieter already, but it could still be improved
> I feel. No doubt the bike hadn't been used very much in the last 6
> months by the previous owner, he had bought himself a brand new Seiran
> Superlight high racer (apparently about 10kg!!).

Strip the paint off the fork leg where the caliper attaches and make
sure it's aligned correctly. A decent bike shop should have a tool for
facing the disk mount correctly.

The worst culprits are usually Hope brakes and Marzocchi forks. Hope are
extra picky about alignment and Marzocchi sometimes put too much paint
on.

If you're using Manitou forks then they've don't it already for you and
they have a more sensible mount too. In that case, clean the rotor with
meths and check the pads aren't greasy. You can burn off some surface
grease with a blowtorch.

Sometimes switching pad compounds will alleviate matters too. Cheap
Shimano hydraulics use 'organic' pads which when wet swell up and absorb
all kinds of rubbish. Changing to sintered pads usually cures squeal.


Shaun

 

[Paul Rose]

"Shaun Murray" <[email protected]> wrote in message
news:spam_only-2D5591.12280421032005@no-dns-yet-212-23-3-119.zen.co.uk...
> In article <[email protected]>,
> "LSMike" <[email protected]> wrote:
> snip<
> Sometimes switching pad compounds will alleviate matters too. Cheap
> Shimano hydraulics use 'organic' pads which when wet swell up and absorb
> all kinds of rubbish. Changing to sintered pads usually cures squeal.

I've had my bike for a couple of months now and mine squeak a bit. When I
took it into the LBS for its first free service I was told they shouldn't
make any noise at all. Apparently my pads had been contaminated by that
spray ptfe stuff that's supposed to drive out moisture etc. I did try and
keep it away from the rotors but now the pads have absorbed the stuff and I
was advised to get new pads. The LBS ground-off a few mils (or whatever they
do) from the pads which improved it slightly and I hoped by using the brakes
over the following few rides might have cured it but I think the LBS is
right, I need new pads!

As for using sintered pads, are they the ones that absorb more heat? I think
I read somewhere that its not recommended to use them in hot, dry
conditions. If that's right, what other option would you advise?
--
Regards, Paul (R)
My Lake District walking site:
www.lakelandwalker.co.uk

 

[LSMike]

Cheers for all the replies. I tend not to let degreaser and other ****
near the pads, but I've no idea what happened before since the bike is
second hand. I'm gonna clean the disk with meths as suggested and take
a thin layer off the pads with some wet and dry on a flat surface.

My brake gets hot, I can get a hiss from the disk with a licked finger
after a single stop from 25mph. I don't dare to do more than a
glancing light touch either.

 

[Shaun Murray]

In article <[email protected]>,
"LSMike" <[email protected]> wrote:

> Cheers for all the replies. I tend not to let degreaser and other ****
> near the pads, but I've no idea what happened before since the bike is
> second hand. I'm gonna clean the disk with meths as suggested and take
> a thin layer off the pads with some wet and dry on a flat surface.
>
> My brake gets hot, I can get a hiss from the disk with a licked finger
> after a single stop from 25mph. I don't dare to do more than a
> glancing light touch either.

If you can still touch it, it's not hot. ;-)


Shaun

 

[Shaun Murray]

In article <[email protected]>,
"timfy" <[email protected]> wrote:


>
> Now I dont mean to be rude but this is the kind of conversation that we have
> concerning 150mph+ motorcycles at 300lb+ weights. Can it really make that
> much difference on a treader. <jumps into trench and keeps head down>

Yes. Having tested disk brakes back to back with multiple compounds on a
long hill and over months and months on test bikes.

There's essentially three pad compounds on mountain bike brakes.

1. Organic

Cheap and works well in dry conditions and has less build up of heat but
they tend to absorb water and muck easier than sintered pads.

2. Sintered

Harder wearing and work better in the wet once you've got them up to
temperature. IMHO every mountain bike brake should have sintered pads
minimum unless it's a weight weenie XC race bike where organics would be
a better bet or dare I say it, v brakes.

3. Kevlar

Much better at coping with heat. Wear quickly. Only of use to
downhillers.


Shimano tend to ship brakes with organic pads in their cheap brakes -
Deore level. As do Hope in all of their brakes (unless they've changed
again). The Shimano ones will wear through very quickly and a set of
Deore hydraulics were the only set I had in testing that wouldn't stop
me on my hill test. I had to use a dry stone wall as a brake. ;-)

Hope's are notoriously bad for transferring heat away from the pads to
the calipers unless you run their 'alpine' kit which they've started
fitting on all brakes now. Sintered pads make the problem worse.

Formula, Hayes and Shimano XT use sintered pads standard. And they work
a treat, especially 4 piston brakes.

Magura seem to mix and match compounds on their brakes depending on the
model but I've never had one that wasn't terrible at overheating and
pumping up on the lever. Currently, I've got a MartaSL brake on one of
my bikes and it's powerful enough but you have to remember to use it
sparingly if you don't want it to heat up and drag.


If I was to pick one brake, it'd be a Formula 4Racing with 185mm front
rotor, 165 rear, some sintered pads, goodrich hoses and a good DOT3
fluid. Then old ShimanoXT 4 pots, then Hayes. I don't really like any of
the others. Depends where you ride though - That's my favourite setting
for hilly country. If I was living somewhere flat, I'd use rim brakes,
they're less hassle, lighter and cheaper. A set of SRAM 5.0 V brakes and
levers is all you need.

Shaun

 

[LSMike]

Shaun Murray wrote:
> In article <[email protected]>,
> "LSMike" <[email protected]> wrote:
>
> > Cheers for all the replies. I tend not to let degreaser and other
****
> > near the pads, but I've no idea what happened before since the bike
is
> > second hand. I'm gonna clean the disk with meths as suggested and
take
> > a thin layer off the pads with some wet and dry on a flat surface.
> >
> > My brake gets hot, I can get a hiss from the disk with a licked
finger
> > after a single stop from 25mph. I don't dare to do more than a
> > glancing light touch either.
>
> If you can still touch it, it's not hot. ;-)
>
>
> Shaun

I take it you don't realise quite how hot things can be and still be
safely touched with a wet finger?

 

[Tony Raven]

Shaun Murray wrote:
>
>
> If you can still touch it, it's not hot. ;-)
>

And if there's a sizzle sound and you leave some skin on the rotor its
hot ;-)

Tony

 

[Simon Brooke]

in message <[email protected]>, timfy
('[email protected]') wrote:

>
> "Shaun Murray" <[email protected]> wrote in message
>
news:spam_only-DB5CF6.13525923032005@no-dns-yet-212-23-3-119.zen.co.uk...
>> In article <YUC%[email protected]>,
>> "Paul Rose" <[email protected]> wrote:
>> >
>> > As for using sintered pads, are they the ones that absorb more
>> > heat? I
> think
>> > I read somewhere that its not recommended to use them in hot, dry
>> > conditions. If that's right, what other option would you advise?
>>
>>
>> Sintered pads contain more metal in them than organic pads so they
>> hold on to heat longer and get hotter. Unless you're a downhiller or
>> constantly drag your brakes they'll be fine in the UK.
>
> Now I dont mean to be rude but this is the kind of conversation that
> we have concerning 150mph+ motorcycles at 300lb+ weights. Can it
> really make that much difference on a treader. <jumps into trench and
> keeps head down

Squeaky noises, you mean, or over-heating disks?

Pedal cycles suffer from squeaky brakes just as badly as powered ones.
Brake fade on pedal cycles is primarily the province of

(i) Lunatic downhillers in places like the alps, and
(ii) Heavily loaded touring tandemistas in similar places.


--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; All in all you're just another nick in the ball
-- Think Droid

 

[Just zis Guy, you know?]

On 21 Mar 2005 00:57:57 -0800, "LSMike" <[email protected]> wrote
in message <[email protected]>:

>My front disk brake is sometimes noisy, especially when I have only
>light pressure on the handle, or when I'm releasing pressure to come to
>a more gentle stop. I've been using the rear brake to feather my
>arrival at traffic lights Is this normal for a well used hydraulic disk
>brake?

Depends. If it's a Magura Julie, then: yes. Otherwise, as the others
say, it needs fettling. Bike shops have a special tool for getting
the mating faces of the caliper attachment points right.


Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
simple, neat and wrong" - HL Mencken

 

[Shaun Murray]

In article <[email protected]>,
"LSMike" <[email protected]> wrote:


> I take it you don't realise quite how hot things can be and still be
> safely touched with a wet finger?

I have disk brake burns which say otherwise.

For that matter, I have rim brake burns which say otherwise. ;-)

Shaun

 

[Shaun Murray]

In article <[email protected]>,
Simon Brooke <[email protected]> wrote:
> Brake fade on pedal cycles is primarily the province of
>
> (i) Lunatic downhillers in places like the alps, and
> (ii) Heavily loaded touring tandemistas in similar places.


Or Todmorden, West Yorks, which is where I did my testing.

Admittedly, it's one particularly nice long steep hill and I'm somewhat
heavier than I should be but it's not out of the realms of possibility
to experience brake fade in the UK.

Shaun

 

[Dave Larrington]

Shaun Murray wrote:
> In article <[email protected]>,
> Simon Brooke <[email protected]> wrote:
>> Brake fade on pedal cycles is primarily the province of
>>
>> (i) Lunatic downhillers in places like the alps, and
>> (ii) Heavily loaded touring tandemistas in similar places.
>
>
> Or Todmorden, West Yorks, which is where I did my testing.
>
> Admittedly, it's one particularly nice long steep hill and I'm
> somewhat heavier than I should be but it's not out of the realms of
> possibility to experience brake fade in the UK.

You can get 'em[1] to go all mushy until they cool down by braking from 60
km/h to a standstill for the traffic lights at the bottom of Pepys Road
SE14...

1 - Hope M4

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
World Domination?
Just find a world that's into that kind of thing, then chain to the
floor and walk up and down on it in high heels. (Mr. Sunshine)