On Sat, 13 Jan 2018 08:08:03 -0000 (UTC), Mad Roger
wrote:

On Thu, 11 Jan 2018 16:55:12 -0500,
Clare Snyder wrote:

Elementary, my dear Watson. There is a HECK of a lot more to brake
pads than just the coefficient of friction - as Ihave been stating
time and time again.

I found out the DOT Edge Code for the OE Toyota shoes which is
NBK LN508 FF
which is made by "Nisshinbo Automotive Manufacturing, Inc.".

It turns out that you were completely correct where I was hoping this
number would be a "holy grail" where I could use it to better compare two
brake shoes in my hands.

To get a better handle on how to interpret the numbers, I called the main
number at AMECA.ORG in Maryland at 202-898-0145 and spoke to the engineer
in charge of that "AMECA Edge Code Markings" cross reference.

It was a long discussion, the net of which is that this code isn't really
for the consumer.

The engineer said it's kind of like the so-called "serial number" on a
tire, or on a package of baked beans, where if something goes wrong, the
government has a way of tracking down whose fault it is. In addition, he
said that the SAE J866 Chase Test is really a quality metric, and not a
performance metric, even though friction is an outcome of the Chase Test.

The engineer did give me all sorts of personal insight into how to buy
brake pads but overall, he said you can't extrapolate very much real-world
decision-making data from the DOT Edge Code.

Of course, if you miraculously find two pads with the same DOT Edge Code,
then there's a 100% chance that it's the same friction material.


UNLESS it's counterfeit (admitedly likely less than 1% chance -
until it is - - - -

Or, if you find any pads with any of the 19 DOT edge codes that cross
reference to the same AMECA registration number 160426 then they too are
exactly the same friction material.
NAC D9011 FF
NAC LN508 FF
NAC N2009 FF
NBK D9011 FF
NBK LN508 FF ==== this is the OE Toyota brake shoes DOT edge code
NBK N2009 FF
NSA D9011 FF
NSA LN508 FF
NSA N2009 FF
NSC D9011 FF
NSC LN508 FF
NSC N2009 FF
SABC D9011 FF
SABC LN508 FF
SABC N2009 FF
SAC D9011 FF
SAC LN508 FF
SAC N2009 FF
SABC LN508 FF

That's because the AMECA registration number 160426 is for a specific
1-inch square piece of friction material that can be used on any brake pad
or shoe.

But that's really as far as a consumer can go with the edge code, he said.

He knew about all three of the Michigan police studies of EE and FF brake
pads, where those in-depth police cruiser tests also said it's hard to
extrapolate real-world performance from just the EE or FF friction code
they tested.

The AMECA engineer said that there are from 10 to 30 compounds in a brake
friction material, where he opined that Toyota spends enormous energy with
what he called the Tier 1 companies (e.g., Nisshinbo for Toyota) optimizing
the compound for each vehicle; but the engineer said that the aftermarket
suppliers (e.g, Centric, Wagner, Akebono, Axxis, etc.) centralize on about
a half dozen formulas for all their offerings.

In summary, the AMECA Edge Code is only "slightly" useful to a consumer, as
it tells the consumer the most information only if numbers match, but if
they don't match, the only three things it tells the consumer are the
manufacturer, the friction coefficient, and the registration number for the
specific friction material.

BTW, I was tempted to call the Nisshinbo senior principle engineer himself
(Tsuyoshi Kondo, +1-586-997-1000, ) who submitted
the 1-inch squares for our particular friction material on October 31st
2017 for repeat testing, but I didn't have the nerve to call him for more
information, especially after the AMECO engineer told me this information
is mostly for law enforcement and government use, and not really intended
for consumer use.

The one thing the AMECA engineer told me over and over again though, is
that what we'd want for comparative purposes, has been studied and studied
by the "smartest guys on the planet", and nobody can agree because of
conflicting interest.

So he sympathized with our needs.