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What metric do you use to estimate remaining brake pad life on a typical economy sedan?



 
 
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  #1  
Old July 30th 20, 06:33 PM posted to rec.autos.tech,alt.home.repair,ca.driving
Arlen Holder[_5_]
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Posts: 14
Default What metric do you use to estimate remaining brake pad life on a typical economy sedan?

What metric do you use to estimate remaining front brake pad life on a
typical economy sedan (assuming normal driving under normal conditions)?

A neighbor's kid was heading off to college where her mother asked me to
take a look at her vehicle, where I found a few things to warn them of
such as this rack and pinion steering boot badly torn for some reason:
<https://i.postimg.cc/L4GHNsQG/boot01.jpg>

I told her that I had never replaced steering boots before so I wasn't even
sure how to diagnose whether she needed just a boot or the whole rack:
<https://i.postimg.cc/s20Fxntb/boot02.jpg>

One of the things I simply noted was they had "x" miles left on their front
brake pads (where there is only one mechanical wear sensor per rotor):
<https://i.postimg.cc/gJB3fdFn/pads01.jpg>

If you look closely, the pad is about the thickness of the backing plate:
<https://i.postimg.cc/pXjK1g0L/pads02.jpg>

The owner asked me how many miles those pads had left under normal driving:
<https://i.postimg.cc/nrD3HTJK/pads03.jpg>

I wasn't sure, so I guessed wildly at roughly about 5 thousand miles to go:
<https://i.postimg.cc/q7NyVq0y/pads04.jpg>

But what metric do you use to estimate a pad's remaining life given only
the thickness of the front pads, and the fact that you are told the vehicle
is driven by a typical owner under typical driving on typical roads?
--
Usenet is great when people offer advice that you might not have known.
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  #2  
Old July 30th 20, 07:25 PM posted to rec.autos.tech,alt.home.repair,ca.driving
Ed Pawlowski[_3_]
external usenet poster
 
Posts: 15
Default What metric do you use to estimate remaining brake pad life on atypical economy sedan?

On 7/30/2020 1:33 PM, Arlen Holder wrote:
> What metric do you use to estimate remaining front brake pad life on a
> typical economy sedan (assuming normal driving under normal conditions)?
>
> A neighbor's kid was heading off to college where her mother asked me to
> take a look at her vehicle, where I found a few things to warn them of
> such as this rack and pinion steering boot badly torn for some reason:
> <https://i.postimg.cc/L4GHNsQG/boot01.jpg>


>
> The owner asked me how many miles those pads had left under normal driving:
> <https://i.postimg.cc/nrD3HTJK/pads03.jpg>
>
> I wasn't sure, so I guessed wildly at roughly about 5 thousand miles to go:
> <https://i.postimg.cc/q7NyVq0y/pads04.jpg>
>
> But what metric do you use to estimate a pad's remaining life given only
> the thickness of the front pads, and the fact that you are told the vehicle
> is driven by a typical owner under typical driving on typical roads?
>


What is normal? Nothing a teenager does is normal.
What I use does not apply unless you are in the same situation.
When I lived in the city, it was a stretch to get 12 to 15,000 miles
from a set of pads. Stop sign on every corner, traffic lights on the
main streets, even the highway would have some stop and go at a couple
of spots.

When I moved to another state and did a lot of highway driving, I got
50,000 miles from pads.

You could measure them now and in 3000 miles to see how much wear and
make a decent calculation from that.
  #3  
Old July 30th 20, 07:43 PM posted to rec.autos.tech
The Real Bev[_5_]
external usenet poster
 
Posts: 553
Default What metric do you use to estimate remaining brake pad life on atypical economy sedan?

On 07/30/2020 11:25 AM, Ed Pawlowski wrote:
> On 7/30/2020 1:33 PM, Arlen Holder wrote:
>> What metric do you use to estimate remaining front brake pad life on a
>> typical economy sedan (assuming normal driving under normal conditions)?
>>
>> A neighbor's kid was heading off to college where her mother asked me to
>> take a look at her vehicle, where I found a few things to warn them of
>> such as this rack and pinion steering boot badly torn for some reason:
>> <https://i.postimg.cc/L4GHNsQG/boot01.jpg>

>
>>
>> The owner asked me how many miles those pads had left under normal driving:
>> <https://i.postimg.cc/nrD3HTJK/pads03.jpg>
>>
>> I wasn't sure, so I guessed wildly at roughly about 5 thousand miles to go:
>> <https://i.postimg.cc/q7NyVq0y/pads04.jpg>
>>
>> But what metric do you use to estimate a pad's remaining life given only
>> the thickness of the front pads, and the fact that you are told the vehicle
>> is driven by a typical owner under typical driving on typical roads?

>
> What is normal? Nothing a teenager does is normal.
> What I use does not apply unless you are in the same situation.
> When I lived in the city, it was a stretch to get 12 to 15,000 miles
> from a set of pads. Stop sign on every corner, traffic lights on the
> main streets, even the highway would have some stop and go at a couple
> of spots.
>
> When I moved to another state and did a lot of highway driving, I got
> 50,000 miles from pads.


I seem to remember 40K on the fronts and 80K on the rears.

> You could measure them now and in 3000 miles to see how much wear and
> make a decent calculation from that.


Don't they put those little metal squeakers on the pads any more? You
can tolerate the squeaking for a long time, the grinding for a shorter
time, and the hogging in for only a VERY short time. Don't ask me how I
know this.

--
Cheers, Bev
Little Mary took her skis upon the snow to frisk.
Wasn't she a silly girl her little * ?
  #4  
Old July 30th 20, 11:36 PM posted to rec.autos.tech,ca.driving,alt.home.repair
Arlen Holder[_5_]
external usenet poster
 
Posts: 14
Default What metric do you use to estimate remaining brake pad life on a typical economy sedan?

On Thu, 30 Jul 2020 11:43:59 -0700, The Real Bev wrote:

> I seem to remember 40K on the fronts and 80K on the rears.


Hi The Real Bev,

Thanks for that information about the front pads, which is what I seek.
o Personally, I get about one thousand miles per millimeter of pad

The goal is to get those who have done the calculation to help out with an
estimate of the number of miles per (whatever) thickness of pad, on
average, that others would get (as I drive on mountainous roads a lot).

People either know how many miles they get, or they don't know it.
o So I thank you for that datapoint of another average'ish driver,

If you get 40K per pad, and if new pads are, oh, hmmmm... how thick?
<https://i.postimg.cc/4NzSKGFr/pads05.jpg>

I happen to have a few sets of "Centric Premium Ceramic" pads lying around,
P/N 301.09080, marked "CEN30109080 31AC9101 GG 02 B19" (i.e., cold/hot
friction rating of G/G, which is a friction coefficient of 0.45-0.55)
<http://www.napbrake.com/2018/02/24/friction-coefficient-brake-pads/>

The backing plate is 6mm & the pad, brand new, is an additional 12mm:
<https://i.postimg.cc/DwnYLN9m/pads06.jpg>

At 40K miles, that's about 40,000miles/12mm = about 3K miles per pad mm.

Given the worn pads are about as thick as the backing plate, that's:
o 6mm times about 3K miles/mm = about 18,000 miles left on those pads

> Don't they put those little metal squeakers on the pads any more? You
> can tolerate the squeaking for a long time, the grinding for a shorter
> time, and the hogging in for only a VERY short time. Don't ask me how I
> know this.


This is what they come with, apparently:
<https://i.postimg.cc/4NzSKGFr/pads05.jpg>

Regarding not asking how you know this, I know that steel on steel has
almost the same cold/hot friction coefficient as many brake pads people buy
(e.g., EE pads) where I've seen rotors worn down to the ribs and the brakes
"still work".

You get three times the miles I get, where I get around one thousand miles
per millimeter of pad, or thereabouts, on my bimmer (OEM Textar/Jurid pads,
with cold/hot friction ratings of F/F), looking at my records, but I live
in hilly country, where people would likely get more on flat land.

If we don't get further data, an average of two thousand miles per
millimeter might be our starting point, in which case that's about twelve
thousand miles left on those worn pads.
--
Usenet is wonderful when everyone pitches in helpfully with knowledge.
  #5  
Old July 31st 20, 12:03 AM posted to rec.autos.tech,ca.driving,alt.home.repair
Scott Dorsey
external usenet poster
 
Posts: 3,877
Default What metric do you use to estimate remaining brake pad life on a typical economy sedan?

Arlen Holder > wrote:
>The goal is to get those who have done the calculation to help out with an
>estimate of the number of miles per (whatever) thickness of pad, on
>average, that others would get (as I drive on mountainous roads a lot).


Teenagers can go through a set of brake pads in ten miles on the track.
assuming they make it ten miles before the clutch wears out.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #6  
Old July 31st 20, 01:38 AM posted to rec.autos.tech,ca.driving,alt.home.repair
Arlen Holder[_5_]
external usenet poster
 
Posts: 14
Default What metric do you use to estimate remaining brake pad life on a typical economy sedan?

On 30 Jul 2020 23:03:32 -0000, Scott Dorsey wrote:

> Teenagers can go through a set of brake pads in ten miles on the track.
> assuming they make it ten miles before the clutch wears out.


This is a college-aged girl who probably has never left skid marks on the
road even once, as I've seen her drive - and it's verrrrrry sloooooow.

Nonetheless, without an actual miles per millimeter of pad, it's not
helpful to tell me everyone is different, and every car is different, and
every road is different, as everyone knows that and so it isn't useful.

It's like claiming there is no such thing as a statistical average.
o There is a statistical average - but it takes data to arrive at it.

All I'm asking for is the data in miles per pad (or miles per millimeter).

I'm leaning toward 1000 miles per millimeter for those who brake hard, and
double to quadruple that (see The Real Bev's response) for normal driving.

All I want is number of miles per pad, where I can do the math (assuming 10
mm of pad is worn away in that time period, leaving 2mm of pad on average).

So far we have only two suitable responses:
1. I get 1,000 miles per millimeter of FF pads (Jurid/Textar)
2. The Real Bev gets about 4,000 miles per millimeter of pad

How many miles per front pad do others get?
--
Usenet is wonderful when everyone pitches in helpfully with knowledge.
  #7  
Old July 31st 20, 03:19 AM posted to rec.autos.tech
[email protected]
external usenet poster
 
Posts: 539
Default What metric do you use to estimate remaining brake pad life on atypical economy sedan?

The Real Bev:

So when the brakes sound like a fog horn when
applied, it's: skip local mechanic(appt required for
next week!!) and head straight for 'Brakes-In-A-
Box'!
  #8  
Old July 31st 20, 08:28 AM posted to rec.autos.tech,ca.driving,alt.home.repair
Xeno
external usenet poster
 
Posts: 347
Default What metric do you use to estimate remaining brake pad life on atypical economy sedan?

On 31/7/20 10:38 am, Arlen Holder wrote:
> On 30 Jul 2020 23:03:32 -0000, Scott Dorsey wrote:
>
>> Teenagers can go through a set of brake pads in ten miles on the track.
>> assuming they make it ten miles before the clutch wears out.

>
> This is a college-aged girl who probably has never left skid marks on the
> road even once, as I've seen her drive - and it's verrrrrry sloooooow.
>
> Nonetheless, without an actual miles per millimeter of pad, it's not
> helpful to tell me everyone is different, and every car is different, and
> every road is different, as everyone knows that and so it isn't useful.
>
> It's like claiming there is no such thing as a statistical average.
> o There is a statistical average - but it takes data to arrive at it.
>
> All I'm asking for is the data in miles per pad (or miles per millimeter).
>
> I'm leaning toward 1000 miles per millimeter for those who brake hard, and
> double to quadruple that (see The Real Bev's response) for normal driving.
>
> All I want is number of miles per pad, where I can do the math (assuming 10
> mm of pad is worn away in that time period, leaving 2mm of pad on average).
>
> So far we have only two suitable responses:
> 1. I get 1,000 miles per millimeter of FF pads (Jurid/Textar)
> 2. The Real Bev gets about 4,000 miles per millimeter of pad
>
> How many miles per front pad do others get?
>

I'm up to 100,000 kilometres on my Toyota front pads and I expect many more.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)
  #9  
Old July 31st 20, 03:25 PM posted to rec.autos.tech,ca.driving,alt.home.repair
Arlen Holder[_5_]
external usenet poster
 
Posts: 14
Default What metric do you use to estimate remaining brake pad life on a typical economy sedan?

On Fri, 31 Jul 2020 17:28:41 +1000, Xeno wrote:

> I'm up to 100,000 kilometres on my Toyota
> front pads and I expect many more.


Thanks Xeno for understanding the question (which some who posted clearly
didn't) and for purposefully helpfully adding another datum to the solution
set (where the more good data we get, the better that average estimate).

Assuming new pads are 12 mm with a margin of 2 mm when replaced, that means
you attain at least 10,000km per millimeter (at least 6,000 miles per mm).

So far, we have the following decent datapoints:
o Jurid/Textar FF front pads at ~1,000 miles per mm (10,000 miles per pad)
o The Real Bev at about 4,000 miles per millimeter (40,000 miles per pad)
o Xeno front pads at about >6,000 miles per mm (>60,000 miles per pad)

One question is how much meat is left on the pad when you replace them.
o I'm assuming 2 mm out of the 12 mm in toto & of course, linear wear

Does that sound about right?
--
Usenet is most useful when adult post with purposefully helpful intent.
  #10  
Old July 31st 20, 07:50 PM posted to rec.autos.tech,ca.driving,alt.home.repair
The Real Bev[_5_]
external usenet poster
 
Posts: 553
Default What metric do you use to estimate remaining brake pad life on atypical economy sedan?

On 07/30/2020 03:36 PM, Arlen Holder wrote:
> On Thu, 30 Jul 2020 11:43:59 -0700, The Real Bev wrote:
>
>> I seem to remember 40K on the fronts and 80K on the rears.

>
> Hi The Real Bev,
>
> Thanks for that information about the front pads, which is what I seek.
> o Personally, I get about one thousand miles per millimeter of pad


That's a memory from long ago. I don't actually KNOW if those are good
numbers.

> The goal is to get those who have done the calculation to help out with an
> estimate of the number of miles per (whatever) thickness of pad, on
> average, that others would get (as I drive on mountainous roads a lot).
>
> People either know how many miles they get, or they don't know it.
> o So I thank you for that datapoint of another average'ish driver,
>
> If you get 40K per pad, and if new pads are, oh, hmmmm... how thick?
> <https://i.postimg.cc/4NzSKGFr/pads05.jpg>
>
> I happen to have a few sets of "Centric Premium Ceramic" pads lying around,
> P/N 301.09080, marked "CEN30109080 31AC9101 GG 02 B19" (i.e., cold/hot
> friction rating of G/G, which is a friction coefficient of 0.45-0.55)
> <http://www.napbrake.com/2018/02/24/friction-coefficient-brake-pads/>
>
> The backing plate is 6mm & the pad, brand new, is an additional 12mm:
> <https://i.postimg.cc/DwnYLN9m/pads06.jpg>
>
> At 40K miles, that's about 40,000miles/12mm = about 3K miles per pad mm.
>
> Given the worn pads are about as thick as the backing plate, that's:
> o 6mm times about 3K miles/mm = about 18,000 miles left on those pads
>
>> Don't they put those little metal squeakers on the pads any more? You
>> can tolerate the squeaking for a long time, the grinding for a shorter
>> time, and the hogging in for only a VERY short time. Don't ask me how I
>> know this.

>
> This is what they come with, apparently:
> <https://i.postimg.cc/4NzSKGFr/pads05.jpg>


That looks too complex. I seem to remember (from the 1983 Sentra) just
a little thin metal tab that stuck out and contacted the rotor at a
chosen point. I bent it more to give me more wear, but I sent the car
to the knackers long before that point.

> Regarding not asking how you know this, I know that steel on steel has
> almost the same cold/hot friction coefficient as many brake pads people buy
> (e.g., EE pads) where I've seen rotors worn down to the ribs and the brakes
> "still work".


That would be me. The rotors looked like a beginning lathe project --
proof that they're made of softer stuff than the pad's backing plate
nubs. I could feel and hear the grinding, but the braking was just as
good as before it started. When I had to brake carefully to avoid
hogging in I figured I needed to deal with the problem. At the time the
rotors (Pep Boys, used) cost only $10 each. The cost wasn't the
problem, just the time.

> You get three times the miles I get, where I get around one thousand miles
> per millimeter of pad, or thereabouts, on my bimmer (OEM Textar/Jurid pads,
> with cold/hot friction ratings of F/F), looking at my records, but I live
> in hilly country, where people would likely get more on flat land.
>
> If we don't get further data, an average of two thousand miles per
> millimeter might be our starting point, in which case that's about twelve
> thousand miles left on those worn pads.


I wouldn't let it go that long now. I love my little Corolla and don't
want to hurt it. Rear drums, but I've never noticed a problem with
insufficient brake power from the rear. OTOH, how would I know?

--
Cheers,
Bev
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^
"Friends help you move. *Real* friends help you move bodies."
--A. Walker
 




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