Hydraulic brake performance question

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Just back from another Copper Canyon run.

shutterfly.comosi.jspOpen ↗

Mtbchip

Rad pix!
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"Chris Phillipo" <[email hidden]> wrote in message
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In article <[email hidden]-
net.or.jp>, [email hidden] says...

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Shaun Rimmer said:

"James Annan" <[email hidden]> wrote in
message -"]news:[email hidden]-
net.or.jp...

>My Hope disk brakes aren't like this, there is a
>piston which moves in the reservoir which seals the
>fluid from the air. Which is just as

well

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>as the fluid absorbs water (and performance suffers
>when that

happens).

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>
>I guess the open end of the chamber is probably not
>air-tight.
>
>James

Uhhmm, which Hopes would they be?!? All the ones I've
seen, and I'm

sure

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other open systems too, for obvious reasons, have a
diaphragm between

the

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fluid and air. This allows fluid expansion and auto
pad wear adjust

without

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allowing the fluid _ANY_ contact with the air.
Allowing the fluid to

have

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contact with the air at regular intervals would be
utter stupidity.

um..I think if you re-read my post you will see that we
are not in disagreement. It was Chris Phillipo who said
that fluid could leak

out...

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James

Aren't hopes closed system brakes? Sounds like a closed
system to me unless you pop that diaphragm.

Only the C2.

'Open system' doesn't mean the fluid has contact with the
big ol' outside.

Shaun aRe

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Aren't hopes closed system brakes? Sounds like a closed
system to me unless you pop that diaphragm.

Only the C2.

'Open system' doesn't mean the fluid has contact with the
big ol' outside.

Shaun aRe

I was speaking about Hayes brakes. They will leak and let
air in if you hang the bike upside down. A flexible membrane
could be fitted but there just isn't enough room and it
wouldn't work without a reservoir anyway.
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Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗
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"Chris Phillipo" <[email hidden]> wrote in message
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Quoted message said:

Quoted message said:

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>

Aren't hopes closed system brakes? Sounds like a
closed system to me unless you pop that diaphragm.

Only the C2.

'Open system' doesn't mean the fluid has contact with
the big ol'

outside.

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Quoted message said:

Shaun aRe

I was speaking about Hayes brakes. They will leak and let
air in if you hang the bike upside down. A flexible
membrane could be fitted but there just isn't enough room
and it wouldn't work without a reservoir anyway.

Well, that sucks! Do yourself a favour and buy yourself some
Hydraulic Disc Brakes - 'Hope'.

',;~}~

Shaun aRe

Quoted message said:

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I was speaking about Hayes brakes. They will leak and
let air in if you hang the bike upside down. A flexible
membrane could be fitted but there just isn't enough
room and it wouldn't work without a reservoir anyway.

Well, that sucks! Do yourself a favour and buy yourself
some Hydraulic Disc Brakes - 'Hope'.

',;~}~

Shaun aRe

I think I will just not hang my bike upside down 🙂
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Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗
online.com

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

Quoted message said:

I was speaking about Hayes brakes. They will leak and let
air in if you hang the bike upside down. A flexible
membrane could be fitted but there just isn't enough room
and it wouldn't work without a reservoir anyway.

That's odd. I've been hanging my bike upside down for
years. Hayes hyraulic disc. No leakage ever. What's the
deal with that? Or let me clarify, I've been hanging
them from the rear wheel, not actually fully upside
down. Is that not enough to make them leak??
(apparently not?)
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In article <[email hidden]>,
[email hidden] says...

Quoted message said:

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

Quoted message said:

I was speaking about Hayes brakes. They will leak and
let air in if you hang the bike upside down. A flexible
membrane could be fitted but there just isn't enough
room and it wouldn't work without a reservoir anyway.

That's odd. I've been hanging my bike upside down for
years. Hayes hyraulic disc. No leakage ever. What's
the deal with that? Or let me clarify, I've been
hanging them from the rear wheel, not actually fully
upside down. Is that not enough to make them leak??
(apparently not?)

Hanging it like that shouldn't be a problem, they don't drip
they just sort of seep over time. If you leave them upside
down for weeks at a time, air gets into the system so you
end up having a soft lever and you have to re-bleed them.
--
_________________________
Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗
online.com

D H said:

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

Quoted message said:

I was speaking about Hayes brakes. They will leak and let
air in if you hang the bike upside down. A flexible
membrane could be fitted but there just isn't enough room
and it wouldn't work without a reservoir anyway.

That's odd. I've been hanging my bike upside down for
years. Hayes hyraulic disc. No leakage ever. What's
the deal with that? Or let me clarify, I've been
hanging them from the rear wheel, not actually fully
upside down. Is that not enough to make them leak??
(apparently not?)

I was gonna say!

Hey Chris, I thought all the Canadian cannabis was located
in central/wester Ca ?? Bro, put the bong down.
--
Slacker

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anyway.

That's odd. I've been hanging my bike upside down
for years. Hayes hyraulic disc. No leakage ever.
What's the deal with that? Or let me clarify, I've
been hanging them from the rear wheel, not actually
fully upside down. Is that not enough to make them
leak?? (apparently not?)

I was gonna say!

Hey Chris, I thought all the Canadian cannabis was located
in central/wester Ca ?? Bro, put the bong down.
--
Slacker

That open vent hole where the fluid weeps out on Hayes
levers could also be used for sucking in the good stuff I
suppose, the caliper makes a good roach clip.
--
_________________________
Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗
online.com

Chris Phillipo said:

That open vent hole where the fluid weeps out on Hayes
levers could also be used for sucking in the good stuff I
suppose, the caliper makes a good roach clip.

The bladder (o-ring material)can and does does sweat a
little when it gets really hot, which is why Hayes have a
vent hole on the perch. Plus, the bladder is covered in o-
ring lube during installation. But it does not suck in air
nor can it... pbase.comhayes brakesOpen ↗ The
only thing that would let air in is component failure/bad
installation.

Your thinking of systems with a reservoir. It's nearly
impossible to have absolutely no air pocket in the
reservoir. This is why Shimano's own documentation states
that turning the bike upside down can introduce air into the
system, which is ridiculous for DH applications... Sheesh,
my bike is upside half the time while riding ;-)
--
Slacker

Quoted message said:

The bladder (o-ring material)can and does does sweat a
little when it gets really hot, which is why Hayes have a
vent hole on the perch. Plus, the bladder is covered in
o-ring lube during installation. But it does not suck in
air nor can it... pbase.comhayes brakesOpen ↗
The only thing that would let air in is component
failure/bad installation.

Your thinking of systems with a reservoir. It's nearly
impossible to have absolutely no air pocket in the
reservoir. This is why Shimano's own documentation states
that turning the bike upside down can introduce air into
the system, which is ridiculous for DH applications...
Sheesh, my bike is upside half the time while riding ;-)
--
Slacker

I guarantee you if you leave your bike upside down long
enough all that fluid that drains into the bladder will work
a small amount out to the vent hole, I honestly can't say if
it's past the threads or if it passed through the rubber
itself when it heats up but it happens. I had assumed Hayes
was using the flange on the small side of the reservoir as a
labyrinth seal like other manufacturers do, meant to let
fluid escape under pressure without rupturing the bladder
but to seal it under normal circumstances. Once fluid does
escape air can be introduced, any air trapped in there is
harmless and will not affect your braking until you turn the
bike upside down and the air bubble is allowed to come in
contact with that hole in the master cylinder/cartridge.
That's why you'll frequently hear people complain their
brake worked fine all day, they hung up the bike and the
next day the lever felt soft.

Shimano's is virtually the same except you can actually see
and fill their reservoir from the outside, but I have not
seen fluid come through their membrane and out the vent hole
except for the rare (but not rare enough) case where the
customer has filled the brake with Dot 4 and the rubber has
gone all wonky.

--
_________________________
Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗
online.com

"Slacker" <[email hidden]> wrote in message
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Quoted message said:

Sheesh, my bike is upside half the time while riding ;-)

Dang, I never thought of that. Good point! :-)
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Shimano's is virtually the same except you can actually
see and fill their reservoir from the outside, but I have
not seen fluid come through their membrane and out the
vent hole except for the rare (but not rare enough) case
where the customer has filled the brake with Dot 4 and the
rubber has gone all wonky.

It should be said also that a direct comparison can't be
made because no one is crazy enough to DH with a pair of
Shimano Deore brakes 🙂
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Chris Phillipo - Cape Breton, Nova Scotia ramsays-ramsays-Open ↗
online.com

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

Quoted message said:

Quoted message said:

Quoted message said:

I was speaking about Hayes brakes. They will leak and
let air in if

you

Quoted message said:

Quoted message said:

Quoted message said:

hang the bike upside down. A flexible membrane could
be fitted but there just isn't enough room and it
wouldn't work without a reservoir anyway.

Well, that sucks! Do yourself a favour and buy yourself
some Hydraulic

Disc

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Brakes - 'Hope'.

',;~}~

Shaun aRe

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I think I will just not hang my bike upside down 🙂

How you gonna do the common stunt known as 'crashing',
then?!?!?

Shaun aRe

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Try again on reason #1. The Avids may be cheaper, but they
are anything but lighter. Prove it to yourself- take off
the lever, cable/housing, caliper and rotor from each and
weigh them... I'm betting that Avid setup is at least
100gm heavier.

Finally got around to doing that.

You're contributing to my suspicion that there are much
lighter disk brake setups than Hope C2's....because the
weights were with five grams of each other - which I
consider to be within my own range of measurement error.

The Avids are probably a teeny bit lighter because the Avid
disc is perceptably lighter than the Hope disc....but I'd
still call it a wash.