Need help INTERPRETING these test results police cruiser SAE J866a Chase Test

On 1/14/18 10:37 AM, Mad Roger wrote:

Ain't gonna happen. The people what know how this shit works aren't going to waste their time arguing with your preconceived misconceptions.
--
"I am a river to my people."
Jeff-1.0
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On Sun, 14 Jan 2018 17:52:27 -0800 (PST), snipped-for-privacy@gmail.com wrote:

I agree with you that the primary role of friction material is their friction, but as the AMECA engineer told me, the way they outgas alone can have an effect that is huge, as you are also noting.
It would be nice to figure out what these second-order effects are, such as outgassing as mentioned by the AMECA engineer, as the police cruiser test already eliminated any second-order effects from a difference in vehicles since they tested the different pads on the exact same vehicle.
So we can tentatively state that you are 100% correct that second-order effects (outgassing) apparently are as big as first-order effects (friction).
The AMECA engineer said that all materials heat up differently, which, he said, also effects the performance of the pads.
So I think we have two potentially high second-order effects which are (shockingly) almost as important as the first-order effect of friction coefficient: 1) outgassing (outgasing sp?) 2) heating 3) ?
What other potentially very high (as high as friction) second-order effects could we have, when we've eliminated the difference in vehicles and driver?
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On Mon, 15 Jan 2018 14:19:45 -0000 (UTC), Mad Roger

Pad vibration - which has an effect on gas venting, counterd by the effect of reduced pad contact
May not be a HUGE difference, but it is possibly a factor. Also heat CONDUCTANCE - metallic pads conduct more heat to the caliper than ceramice - making the boiling point of the fluid more critical (if running metallic or semi-metalic pads you want to be sure to be running DOT4, not DOT3, and you want it freash and dry) One reason Chrysler was using composite pistons for several years in the early no-asbestos days (until they found the pistons swelled and stuck - - - )
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Clare Snyder posted for all of us...

They used to be a bitch to get out.
To Madman: When I was early in emergency services I used to run my private vehicle. I had to pay attention to braking because after 3 stops there were NO brakes. I got the police shoes because I was all into it. What a difference! When I got a pursuit certified vehicle it was wonderful. They are designed and built to endure punishment. Try and go to the dealer and get the model, good luck with that. Watch what happens on one of the police shows. See which car is destroyed or smoking at the end. The actors can't make the corner because they got no brakes. Or the engine expires. Something is to be said when one goes from 0 to 40 then 40 to 0 repeatedly and sit there idling for the next 1/2 hour then going to the next call. Then there were the ambulances and fire trucks. *Training*
--
Tekkie

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On Mon, 15 Jan 2018 17:01:47 -0500, Tekkie+AK4- wrote:

I've never experienced such fade in my life, and I drive a performance car, where I've driven down many a long hill. I don't know why I have never experienced brake fade, but I know it exists. I just have never felt it.
But I've never put in less than FF pads either.
That may or may not be related - we can't tell. It's just a datum.

What's a "police shoe"?
The police report from Michigan tested "regular" shoes only.

If there was a difference, it's hard to tell because nobody (except the police in Michigan it seems) tests *new* pads against *new* pads (after burnishing).
You probably didn't as nobody does.
You probably tested *old* pads against *new* pads, and even if you did test apples to apples, it's not extensible to "my" car or to anyone else's car.
That's the problem with tiny experiments of a single datapoint.

What the heck is a "pursuit certified vehicle"? I drove an EMT vehicle many times. It drove like a truck.

Like any performance vehicle on the road today?

Don't even know what it is. Is it a souped up police cruiser?

That's not a good scientific test.

I have been trained to drive an ambulance. Know what they taught me?
a. Defensive driving b. Noise pollution is bad c. Laws (nobody is allowed to break the law in that state, not even ambulances)
I think in some states emergency vehicles *are* allowed to break the law, but not in that state where I drove the ambulance. Of course, nobody is going to give you a ticket either, but if you kill someone while breaking the law, the onus is on you.
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On Tue, 16 Jan 2018 02:10:28 -0000 (UTC), Mad Roger

The shoes they tested were premium and heavy duty (all of the FF and FG were "heavy duty" pads.
On Persuit rated vehicles they oftern also have larger rotors and drums - as well as different tires, and even different RIMS to allow bwtter brake cooling. Never wondered why cruisers have "dog dish" hub caps instead of full wheel covers??? To allow the brakes to "breath" better.

I can say without reservation that the "police duty" and severe duty brakes were MUCH better at high speeds than standard brakes (and sometimes not nearly as good when cold/low speed) 1 1966 Dodge Polara Pursuit Special I drove for a short time went like a scalded cat, and stopped like you had jammed a stick into a hole in the pavement.

Yes.

Todays persuit special vehicles are often the big ecoboost engine on fords, and Hemis on Chargers. Often with a "special tune" that raises the rev limiter setting and reprograms the tranny shift points - as well as having bigger rads, bigger alternators, honking big sway bars and super-duty shocks and springs.
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Mad Roger posted for all of us...

Then you have been poorly trained. Our company had mandatory EVOC (Emergency Vehicle Operations Course) training by a certified instructor & recertification. PA is a "due regard" state. Look it up. You can't help if the vehicle is crashed. You are responsible for the crew and victims.
--
Tekkie

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On Mon, 15 Jan 2018 12:23:01 -0500, Clare Snyder wrote:

That makes sense that the outgassing of pad A can be vastly different than that of pad B, and, in fact, they "burnished" the pads in the police test to minimize the initial presumed-far-greater effect of that as the adhesives heated up for the first time and vented gases.

Occam's Razor logic tells us that only one of 2 things is happening: a. There is a huge as-yet-unnamed second-order effect, or, b. There is a combination that results in a huge second-order effect.
That there is a huge second-order effect (after friction), there can be no logical doubt.
But what is the 2nd-order effect's cause and can we test for it?

Two Occam's Razor points on that observation above, which is correct.
1. While this vehicle specs DOT3, I'll put in DOT4 instead. 2. Metal versus semi-metallic versus ceramic is marketing bullshit
I know there are no laws that differentiate between metal, ceramic, and semi-metallic - as I've personally spoken to the people who make the Axxis/PBR/Metalmasters pads. They told me it's all bullshit only they said it far more politely and less succinctly than I just did.
Suffice to repeat that a spec of dust makes a pad ceramic, just as a spec of iron makes it semi-metallic.
I posit marketing came up with these wonderful good/better/best number-line decisions for people since people (like Terry Schartz seems to be) want a simple number line instead of those oh-so-very-complex quality specifications.
Where's Jeff Liebermann when you need him!!!!!!!!!!!!!!!!!!!! :)
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On Tue, 16 Jan 2018 02:10:28 -0000 (UTC), Mad Roger

Most definitely is NOT marketing Bullshit. It is solid engineering

You speak mandarin, do you? There may not be "legal" definitions, but there are industry accepted definitions - and I've sent you numerous referencesthat spell them out pretty clearly. Yes, there are "hybrids" that sort of bridge the gap - but MOST of them are identified as such.

Most definirely not. There is a small percentage of metal even in organic pads, and the metal does not need to be iron. And "ceramic" has nothing to do with "dust".
A ceramic is a vitified clay base which may or may not have metals also included. A ceramic does not use phenol;ic binders.
Again - READ the stuff I posted for you.

You are being a paranoid simleton.

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On Mon, 15 Jan 2018 07:54:12 -0800 (PST), Terry Schwartz wrote:

I get your point, even ensconced inside the sarcasm, so I'll just say it bluntly that I do realize 99.99% of the people out there do not care that they're completely unable to intelligently purchase things using a modicum of logic.
These people all want a "number line" decision, where they can use the good, better, best by "marketing derived" criteria, such as silly words like "ceramic" (where one spec of clay makes it a ceramic) and "semi-metallic" (where one spec of iron makes it metallic).
You're one of those people, most likely (based on Occam's Razor deduction), and that's fine.
You *think* you're intelligently choosing a brake pad, and that's fine too.
You may even buy by one of the three marketing-induced criteria: a. If you're cost conscious, you buy the cheapest FF that fits. b. If you're value conscious, you buy the mid FFs (with a small price bump) c. If you're status conscious, you buy the high FFs (bigger price jump)
I'm not like you. I like to *understand* that which I buy.
That's my take on the main difference between you and me base on the one line you wrote.
I like to make intelligent buying decisions. You apparently don't care to - and that's fine.
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On Tue, 16 Jan 2018 02:10:29 -0000 (UTC), Mad Roger

And YOU think YOU are smart. (nobody else does - sorry to break your bubble)

and if you are SMART you buy the type of pad that matches yourdriving requirements - which for most commuters is a standard organic pad, for heavy duty use, a semi metallioc, and for high speed light duty, generally a ceramic.

And yet you most certainly do NOT when it comes to brakes. You are totally clueless and uneducatable

and you seem to be totally incapable of it.
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On 16/01/2018 1:58 PM, Clare Snyder wrote:

I caught on to that very early in the piece. That's why I deduced that discussion with mad roger was not a fruitful use of my time.
As you have discovered.

Amen to that! Just wants to argue the toss, that is all.

He is.
--

Xeno

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On 2018-01-11 06:46, Mad Roger wrote:

Bollox bollox bollox.
Momentum and energy are quite different quantities, if you want to play properly at being a scientist.
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On Sun, 14 Jan 2018 17:58:04 -0800 (PST), snipped-for-privacy@gmail.com wrote:

That's why I say those who say "you get what you pay for" are misguided because a $157 pad "might" be just as good or bad as a $20 pad, where I can prove this statement for the $300 20W Panasonic speakers in a Toyota since I know the specs on the $50 speakers at Crutchfields.
Even at Crutchfields, you can get a good $50 speaker or a less-good $50 speaker, and the price is exactly the same.
So if someone tells me "you get what you pay for", they'll get the same rant from me that everyone loves to pick products off a number line, but the real number line is a bunch of specs, and not a simple price.
That's retail for you! :)

I think price is not an indication of anything other than what the marketing can make people pay. It's certainly not an indication of quality.

I'm not sure what you mean by "scrapyards". To me, that means a junk yard, which contains dead cars. I wouldn't buy brakes off a dead car for a billion reasons which are obvious so I shouldn't need to state it.
What's the difference between my concept of a junkyard (which contains entire cars that were thrown away) and your scrapyard?
Are you talking about *used* brake pads or *new* brake pads?

There is no other logical conclusion to be made, given the information we have. Price is NOT the determinant of a good or bad brake pad.
The sad thing is that there is no determinant we can make that will hold true other than there is no difference practically that you can do anything about.
I'm NOT saying they are all the same. I'm saying we consumers can't tell by having two of them in our hand or having two of them sold online.

Or rubber in bicycle brakes.
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On Mon, 15 Jan 2018 14:19:40 -0000 (UTC), Mad Roger

You still have not learned ANYTHING?????
The specs on speakers are known to be some of the best fiction ever written, followed only by the specs on consumer stereo equipment.

You "only" get what you pay for - and then only if you are both lucky and astute. You SELDOM get more than what you pay for
You can take THAT to the bank.

Because someone was unloading something they didn't need, at a price to get it off their shelves - and your requirements were not severe enough to require anything better.
I've also been "lucky" enough to pick up some real "bargoons" by being at the right place at the right time. I often buy what no-one wants any more - nobody inOntario wanted a 1972 Pontiac Firenza in 1974 or 1975 - so I gor an almost pristine Vauxhaul Viva HC Magnum coupe for $75 - and it served me well for a number of years before I sold it to a friend of my wife, who needed a car and had no money for something "good" - and she drove it another 7 years untill it required a part that was not readily available or available at a decent cost .
I got "more than my money's worth" - I got "more than I paid for".
The same with my current pickup truck which I bought for $1500 because nobody wanted a meticulously maintained 16 year old ford Ranger with over 300,000km on it. It's been virtually trouble free for 6 years - I've spent about $1500 on repairs over more than 50,000km, and all indications areI'll get a few more years out of it. I got more than my money's worth.
In both cases It was because I new the "value" of what I was buying better than both the seller and other potential buyers.
You are FAR more likely to get less than you paid for - particularly when buying any commodity new at retail - where you are SIGNIFICANTLY less likely to get more than you pay for.
Price is not an accurate predictor of quality, but with a few other often obvious clues, it is a pretty reliable indicator.

It is, as I have stated, an indicator, but not a predictor or guarantee of quality.

No they are not - and in MANY places it is illegal to sell used brake parts and used exhaust/emission parts.

Sometimes a car ends up in a scrapyard with lots of brand new parts on it. The owner puts $3000 into making it safe to drive - new brakes, suspension,and tires - the either has it hit, or blows a motor or transmission, and decides not to keep it and repair it - or they spend all kinds of money fixing it up - making it into their ":boy racer's wet dream" and then cannot get it to pass smog - and it ends up in the scrapyard with LOTS of good and/or expensive parts on it.
That said - as a matter of principal - unless no other adequate source of brake parts was available, I'd be looking elsewhere - first. Have I used "used" brake parts in the past?? Yes. I put a complete used rear axle from a '63 Belvedere into my '53 Coronet - brakes and all - as an upgrade when the originals failed and OEM parts were not readilly available, and the old design was less than optimal. ANd I put used parts on my '49 VW in Livingstone Zambia. Where was I going to get new parts??????? On a Sunday afternoon half way between Choima and Macha - (look it up on Google Earth - and keep in mind this was 44 years ago - - - - .

Not necessarilly.

Perhaps not of a good one, but quite often of an inferior one

again, bushels of bovine excrement.

And why do you, like so many "millenials" (I'm aking an assumption here from significant evidence) INSIST on buying everything on-line????

Obviously not sufficientfor a 3 ton vehicle going 100MPH - and definitely not as good after a long downhill stop - -- but likely, at low speeds - al ot better than you suspect!!!

There is SIGNIFICANT difference between different compounds of "rubber" pads for rim brakes - includingin their stopping power and their destructive effect on rims - some better for chromed rims, and others for Alloy rims - some working better for side-pull, and others for center pull (different amounts of pressure available)
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wrote:

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wrote:

And here is some more real good information on brake pad materials - on a lower level - for the non-engineers out there.
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wrote:
More of "all you ever wanted to know about friction materials" but were afraid to ask - - -
http://www.sae.org/events/bce/tutorial-bahadur.pdf
and
http://www.tomorrowstechnician.com/understanding-friction-and-formulations/
and
http://www.mdpi.com/2075-4442/4/1/5/htm
and
http://www.marathonbrake.com/products/varied-application/ub/
and
https://info.ornl.gov/sites/publications/Files/Pub57043.pdf
and
a whole lot more!!!!!!!!!!!
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On Mon, 15 Jan 2018 16:31:56 -0500, Clare Snyder wrote:

I'm reading them as soon as I post this to let you know that... Thanks for always posting on-topic technical value.
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On Tue, 16 Jan 2018 08:45:56 -0800 (PST), snipped-for-privacy@gmail.com wrote:

Yup. Basic Economics 101. Price is only a function of demand.
Price is never directly related to quality. Price is only a function of demand.
Demand is a function of lots of complex variables, which is why they invented Marketing (to greatly influence the demand).

I can't imagine buying used brake shoes or pads off a scrapped car. I just can't.

Whoever proposes to buy brake pads and shoes off of junked cars is fine with his logic, but he doesn't need to repeat it since it's not something most of us would do.
I can see buying some parts at a scrap yard (e.g., a door or a fender), but I just can't see buying a brake pad or shoe off a scrapped car.
How do you even do that? Do you walk around the junk yard to look for your exact year, make and model and then pull the wheels and then pull the pads?
That's a lot of work, if you even find the right make and model, and then if you can get to it (since they pile these things five cars high sometimes) and if you can get the rusted lug bolts and brake drums off and then you have to disassemble the brakes.
Seems like a *lot* of work for a brake shoe that will be "iffy" because you have no way of knowing their condition ahead of time.
Or, maybe the junk yard does that for you, but then you are just staring at a pile of brake shoes on the wall, which maybe, if you're lucky, have accurate designations for the make and model of the vehicle they came off of.
I guess if you bring your old shoes with you, you can match them, but that means your car is on blocks the whole time you do this, so you have to have a second vehicle to do it.
I just don't see *how* it's practicable. Do you?
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