[OT] car brakes

On 2008-05-04, A Muzi wrote:
Peter Cole wrote:
Cross-drilled seems to be more about looks than anything else. "Vented"
or "ventilated" rotors are another matter. They appear to be reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).

Robert Lorenzini wrote:
Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.

Michael Press wrote:
What is the chemical composition of the boiling gasses?
Do the boiling gasses come from the pads?

Counterintuitive, isn't it? This guy thinks it happens:
http://www.innerauto.com/Auto_Part/Brake_Disc/

I'm not convinced ('gas' goes in the little hole??) or that taking one's
foot off a brake can break it.

If gas did come off the pad where it touched the disk then it would have
nowhere to go except to try and squeeze round the edge of the pad or
build up into a sort of bubble. Either way the gas pressure would try to
push pad and disk apart. The holes would prevent that happening.

So I can see how the holes would work if the gas is there.

And just because I don't know what gas would come off brake pads doesn't
mean no gas does. After all what I don't know about brake pads would
fill a book.

On Sun, 04 May 2008 16:16:57 -0500, A Muzi
wrote:

Peter Cole wrote:
Cross-drilled seems to be more about looks than anything else. "Vented"
or "ventilated" rotors are another matter. They appear to be reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).

Robert Lorenzini wrote:
Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.

Michael Press wrote:
What is the chemical composition of the boiling gasses?
Do the boiling gasses come from the pads?

Counterintuitive, isn't it? This guy thinks it happens:
http://www.innerauto.com/Auto_Part/Brake_Disc/

I'm not convinced ('gas' goes in the little hole??) or that taking one's
foot off a brake can break it.

These guys just say 'ducted', which is what I thought this conversation
was about earlier:
http://www.lexus.com/models/IS/featu...sc_brakes.html


You don't need a scientific analasys to KNOW it happens. What happens
if you really brake hard, or just drag the brakes for a while?
Sniff - sniff- smell that strong, pungent smell of burning brakes?

That is SEVERE pad gassing. It occurs at a much lower rate under
normal severe braking. Letting that "gas" away from the pads will
enhance the high temperature braking performance - whether released by
cross-drilling a (vented) rotor, or through grooving of the rotors.

** Posted from http://www.teranews.com **

On Sun, 04 May 2008 14:23:21 -0500, Tom Sherman
wrote:

Kerry Montgomery wrote:
"Ben C" wrote in message
...
On 2008-05-04, Robert Lorenzini wrote:
On Sat, 03 May 2008 21:06:41 GMT, Peter Cole
wrote:
Cross-drilled seems to be more about looks than anything else. "Vented"
or "ventilated" rotors are another matter. They appear to be reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).

Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.
Do you know what gasses these are and how or why they are produced?

Jobst reckons this theory is myth and lore, and it does sound pretty
unlikely, but perhaps if more of the details were explained it wouldn't
seem so implausible.

Ben C,
Vented is not cross-drilled or slotted. Vented is:
http://images.outdoorinteractive.net/mgen/530211_oi.jpg
cross-drilled is:
http://www.camarotech.com/images/Bra...ossDrilled.jpg
slotted is:
http://ecx.images-amazon.com/images/...LL._AA160_.jpg
Don't know about steel or iron brake disk rotors, but the carbon ones used
on F1 racing cars (with carbon pads) don't have cross-drilling or slotting,
but do have venting.

What do you call this type of rotor:
http://farm3.static.flickr.com/2249/2163925995_f7a5dd2a3b.jpg?v=0?
Eyecandy.
** Posted from http://www.teranews.com **

In article ,
Ben C wrote:

On 2008-05-04, A Muzi wrote:
Peter Cole wrote:
Cross-drilled seems to be more about looks than anything else. "Vented"
or "ventilated" rotors are another matter. They appear to be reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).

Robert Lorenzini wrote:
Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.

Michael Press wrote:
What is the chemical composition of the boiling gasses?
Do the boiling gasses come from the pads?

Counterintuitive, isn't it? This guy thinks it happens:
http://www.innerauto.com/Auto_Part/Brake_Disc/

I'm not convinced ('gas' goes in the little hole??) or that taking one's
foot off a brake can break it.

If gas did come off the pad where it touched the disk then it would have
nowhere to go except to try and squeeze round the edge of the pad or
build up into a sort of bubble. Either way the gas pressure would try to
push pad and disk apart. The holes would prevent that happening.

So I can see how the holes would work if the gas is there.

And just because I don't know what gas would come off brake pads doesn't
mean no gas does. After all what I don't know about brake pads would
fill a book.

What gas evolves, what is its chemical composition,
and its partial pressure?

--
Michael Press

In article ,
clare at snyder dot ontario dot canada wrote:

On Sun, 04 May 2008 16:16:57 -0500, A Muzi
wrote:

Peter Cole wrote:
Cross-drilled seems to be more about looks than anything else. "Vented"
or "ventilated" rotors are another matter. They appear to be reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).

Robert Lorenzini wrote:
Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.

Michael Press wrote:
What is the chemical composition of the boiling gasses?
Do the boiling gasses come from the pads?

Counterintuitive, isn't it? This guy thinks it happens:
http://www.innerauto.com/Auto_Part/Brake_Disc/

I'm not convinced ('gas' goes in the little hole??) or that taking one's
foot off a brake can break it.

These guys just say 'ducted', which is what I thought this conversation
was about earlier:
http://www.lexus.com/models/IS/featu...sc_brakes.html


You don't need a scientific analasys to KNOW it happens. What happens
if you really brake hard, or just drag the brakes for a while?
Sniff - sniff- smell that strong, pungent smell of burning brakes?

What gas evolves?
What is its partial pressure?

That is SEVERE pad gassing. It occurs at a much lower rate under
normal severe braking. Letting that "gas" away from the pads will
enhance the high temperature braking performance - whether released by
cross-drilling a (vented) rotor, or through grooving of the rotors.

--
Michael Press

"Tom Sherman" wrote in message
...
Kerry Montgomery wrote:
"Ben C" wrote in message
...
On 2008-05-04, Robert Lorenzini wrote:
On Sat, 03 May 2008 21:06:41 GMT, Peter Cole
wrote:
Cross-drilled seems to be more about looks than anything else.
"Vented"
or "ventilated" rotors are another matter. They appear to be
reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).

Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.
Do you know what gasses these are and how or why they are produced?

Jobst reckons this theory is myth and lore, and it does sound pretty
unlikely, but perhaps if more of the details were explained it wouldn't
seem so implausible.

Ben C,
Vented is not cross-drilled or slotted. Vented is:
http://images.outdoorinteractive.net/mgen/530211_oi.jpg
cross-drilled is:
http://www.camarotech.com/images/Bra...ossDrilled.jpg
slotted is:
http://ecx.images-amazon.com/images/...LL._AA160_.jpg
Don't know about steel or iron brake disk rotors, but the carbon ones
used on F1 racing cars (with carbon pads) don't have cross-drilling or
slotting, but do have venting.

What do you call this type of rotor:
http://farm3.static.flickr.com/2249/2163925995_f7a5dd2a3b.jpg?v=0?

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful


Tom,
I don't know - maybe high void-ratio rotationally slotted but transversely
compliant?
And, pretty as it is, it doesn't have the mathematical artistry of:
http://www.rider-inc.com/Ti_Rotor_Pi...Rotor_Frnt.jpg
Kerry

Michael Press wrote:
In article ,
clare at snyder dot ontario dot canada wrote:

On Sun, 04 May 2008 16:16:57 -0500, A Muzi
wrote:

Peter Cole wrote:
Cross-drilled seems to be more about looks than anything else. "Vented"
or "ventilated" rotors are another matter. They appear to be reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).
Robert Lorenzini wrote:
Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.
Michael Press wrote:
What is the chemical composition of the boiling gasses?
Do the boiling gasses come from the pads?
Counterintuitive, isn't it? This guy thinks it happens:
http://www.innerauto.com/Auto_Part/Brake_Disc/

I'm not convinced ('gas' goes in the little hole??) or that taking one's
foot off a brake can break it.

These guys just say 'ducted', which is what I thought this conversation
was about earlier:
http://www.lexus.com/models/IS/featu...sc_brakes.html

You don't need a scientific analasys to KNOW it happens. What happens
if you really brake hard, or just drag the brakes for a while?
Sniff - sniff- smell that strong, pungent smell of burning brakes?

What gas evolves?
What is its partial pressure?

or in your case, "what is its diffusion rate"? schmuck.



That is SEVERE pad gassing. It occurs at a much lower rate under
normal severe braking. Letting that "gas" away from the pads will
enhance the high temperature braking performance - whether released by
cross-drilling a (vented) rotor, or through grooving of the rotors.

On Sun, 04 May 2008 19:58:31 -0700, Michael Press
wrote:

In article ,
clare at snyder dot ontario dot canada wrote:

On Sun, 04 May 2008 16:16:57 -0500, A Muzi
wrote:

Peter Cole wrote:
Cross-drilled seems to be more about looks than anything else. "Vented"
or "ventilated" rotors are another matter. They appear to be reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).

Robert Lorenzini wrote:
Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.

Michael Press wrote:
What is the chemical composition of the boiling gasses?
Do the boiling gasses come from the pads?

Counterintuitive, isn't it? This guy thinks it happens:
http://www.innerauto.com/Auto_Part/Brake_Disc/

I'm not convinced ('gas' goes in the little hole??) or that taking one's
foot off a brake can break it.

These guys just say 'ducted', which is what I thought this conversation
was about earlier:
http://www.lexus.com/models/IS/featu...sc_brakes.html


You don't need a scientific analasys to KNOW it happens. What happens
if you really brake hard, or just drag the brakes for a while?
Sniff - sniff- smell that strong, pungent smell of burning brakes?

What gas evolves?
What is its partial pressure?

That is SEVERE pad gassing. It occurs at a much lower rate under
normal severe braking. Letting that "gas" away from the pads will
enhance the high temperature braking performance - whether released by
cross-drilling a (vented) rotor, or through grooving of the rotors.


From the smell I would suspect some sort of a Phenol.Perhaps some
formaldehyde as well.
This is born out by other FACTS which we KNOW.
1)The resin binders in most brake pads are phenolic and novolac
resins.(composed of Phenols and formaldehydes, among other
components)They decompose at aprox 450C by charring and
evaporation.The addition of wood flour to alleviate the brittle nature
of Phenolics adds another outgassing agent - when wood is heated
carbon compunds outgas as carbon monoxide amont other compounds.

2)COPNA resin , an abbreviation of ‘condensed polynuclear aromatic’
resin is also used in high performance brake friction material. It
decomposes at the same temperature but outgasses somewhat less.

3)Silicone modified resins,also referred to as phenolic siloxane
resins are still phenolic based and also outgas - but at a somewhat
higher temperature.

4)Cyanate ester resins are brittle like phenolics but handle higher
temperatures - with significantly less outgassing.

5)Anhydride modified epoxy resins stand up to heat of 400C, but wear
more quickly above about 260C, so are generally used to modify
Phenolics - which means you still get phenol and formaldehyde
outgassing somewhere between 350 and 400C.

6)Thermoplastic polyimide resin ,the product of fluoro resin and
calcium carbonate is more thermally stable and therefore causes less
fade but has the shortfall of being a poor conductor of heat (1/3 as
good as Phenolic), so brake linings tend to run MUCH hotter with TPR
binders.They have had very limited use for this reason.
** Posted from http://www.teranews.com **

On Sun, 4 May 2008 20:15:33 -0700, "Kerry Montgomery"
wrote:


"Tom Sherman" wrote in message
...
Kerry Montgomery wrote:
"Ben C" wrote in message
...
On 2008-05-04, Robert Lorenzini wrote:
On Sat, 03 May 2008 21:06:41 GMT, Peter Cole
wrote:
Cross-drilled seems to be more about looks than anything else.
"Vented"
or "ventilated" rotors are another matter. They appear to be
reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).

Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.
Do you know what gasses these are and how or why they are produced?

Jobst reckons this theory is myth and lore, and it does sound pretty
unlikely, but perhaps if more of the details were explained it wouldn't
seem so implausible.

Ben C,
Vented is not cross-drilled or slotted. Vented is:
http://images.outdoorinteractive.net/mgen/530211_oi.jpg
cross-drilled is:
http://www.camarotech.com/images/Bra...ossDrilled.jpg
slotted is:
http://ecx.images-amazon.com/images/...LL._AA160_.jpg
Don't know about steel or iron brake disk rotors, but the carbon ones
used on F1 racing cars (with carbon pads) don't have cross-drilling or
slotting, but do have venting.

What do you call this type of rotor:
http://farm3.static.flickr.com/2249/2163925995_f7a5dd2a3b.jpg?v=0?

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful


Tom,
I don't know - maybe high void-ratio rotationally slotted but transversely
compliant?
And, pretty as it is, it doesn't have the mathematical artistry of:
http://www.rider-inc.com/Ti_Rotor_Pi...Rotor_Frnt.jpg
Kerry

More "eye candy"
** Posted from http://www.teranews.com **

clare at snyder dot ontario dot canada wrote:
On Sun, 04 May 2008 19:58:31 -0700, Michael Press
wrote:

In article ,
clare at snyder dot ontario dot canada wrote:

On Sun, 04 May 2008 16:16:57 -0500, A Muzi
wrote:

Peter Cole wrote:
Cross-drilled seems to be more about looks than anything else. "Vented"
or "ventilated" rotors are another matter. They appear to be reasonably
effective, but it's not a *huge* effect (+40%, rather than 100%).
Robert Lorenzini wrote:
Vented (cross-drilled or slotted) rotors came from racing brakes
which use pads that boil gasses under heat. This is most noticeable
when bedding green pads and they act just like a tire hydroplaning
until most of the volatiles have disapated.
Michael Press wrote:
What is the chemical composition of the boiling gasses?
Do the boiling gasses come from the pads?
Counterintuitive, isn't it? This guy thinks it happens:
http://www.innerauto.com/Auto_Part/Brake_Disc/

I'm not convinced ('gas' goes in the little hole??) or that taking one's
foot off a brake can break it.

These guys just say 'ducted', which is what I thought this conversation
was about earlier:
http://www.lexus.com/models/IS/featu...sc_brakes.html

You don't need a scientific analasys to KNOW it happens. What happens
if you really brake hard, or just drag the brakes for a while?
Sniff - sniff- smell that strong, pungent smell of burning brakes?
What gas evolves?
What is its partial pressure?

That is SEVERE pad gassing. It occurs at a much lower rate under
normal severe braking. Letting that "gas" away from the pads will
enhance the high temperature braking performance - whether released by
cross-drilling a (vented) rotor, or through grooving of the rotors.


From the smell I would suspect some sort of a Phenol.Perhaps some
formaldehyde as well.
This is born out by other FACTS which we KNOW.
1)The resin binders in most brake pads are phenolic and novolac
resins.(composed of Phenols and formaldehydes, among other
components)They decompose at aprox 450C by charring and
evaporation.The addition of wood flour to alleviate the brittle nature
of Phenolics adds another outgassing agent - when wood is heated
carbon compunds outgas as carbon monoxide amont other compounds.

2)COPNA resin , an abbreviation of ‘condensed polynuclear aromatic’
resin is also used in high performance brake friction material. It
decomposes at the same temperature but outgasses somewhat less.

3)Silicone modified resins,also referred to as phenolic siloxane
resins are still phenolic based and also outgas - but at a somewhat
higher temperature.

4)Cyanate ester resins are brittle like phenolics but handle higher
temperatures - with significantly less outgassing.

5)Anhydride modified epoxy resins stand up to heat of 400C, but wear
more quickly above about 260C, so are generally used to modify
Phenolics - which means you still get phenol and formaldehyde
outgassing somewhere between 350 and 400C.

6)Thermoplastic polyimide resin ,the product of fluoro resin and
calcium carbonate is more thermally stable and therefore causes less
fade but has the shortfall of being a poor conductor of heat (1/3 as
good as Phenolic), so brake linings tend to run MUCH hotter with TPR
binders.They have had very limited use for this reason.
** Posted from http://www.teranews.com **

sweet.