Author Topic: Brake pads  (Read 3286 times)

tyler2016

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Brake pads
« on: February 13, 2018, 04:30:13 PM »
I am in the market for brake pads. It isn't urgent, but I will need them in a year or so. I usually get cheapish ceramic pads with shims for 15 to 20 dollars. I have never had a problem with noise, dust, stopping power, or rotor wear. Is there any reason to buy the more expensive ones? Why?

HipGnosis

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Re: Brake pads
« Reply #1 on: February 13, 2018, 08:25:23 PM »
Not enough information to base an answer upon

lthenderson

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Re: Brake pads
« Reply #2 on: February 14, 2018, 07:02:10 AM »
The last time I had my brake pads replaced by a brake shop, they put in some expensive ones that squealed terrible. They tweaked those a couple times and put on a set of cheap ones that they also carry. Same result. On my fifth trip to the shop, I made them order the OEM ones and put them on. That solved the problem. Until I hear otherwise, I will never put non-OEM brake pads on any of my vehicles.

EricEng

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Re: Brake pads
« Reply #3 on: February 14, 2018, 01:38:08 PM »
Supposedly cheap ones will damage your rotors more, but I haven't noticed it.  Noise never bothered me much, so I stick with cheap ones from Autozone.

GuitarBrian

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Re: Brake pads
« Reply #4 on: February 14, 2018, 02:47:26 PM »
I use AutoZone Duralast brake pads. All the pads I've replaced in the last few years have had lifetime warranty. So you just take the worn out ones in and they give you a new pair. Other stores operate the same way I believe.

If you want to get the pads before you take the old ones off, you can do that as well. Just take the old ones back and they'll refund your money.

This works on the cheap ones and the top $$ ones too.

sequoia

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Re: Brake pads
« Reply #5 on: March 05, 2018, 11:09:29 PM »
Brake pads and tires, I do not buy the cheapest option. Either OEM or better. I usually replace them every 4-5 year, so imo the cost difference is negligible.

I am all for making my cars stop faster, not because I drive like a maniac, but it maybe the difference between hitting and avoiding that little kid that run across the street in front of me.

EricEng

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Re: Brake pads
« Reply #6 on: March 06, 2018, 11:42:12 AM »
Brake pads and tires, I do not buy the cheapest option. Either OEM or better. I usually replace them every 4-5 year, so imo the cost difference is negligible.

I am all for making my cars stop faster, not because I drive like a maniac, but it maybe the difference between hitting and avoiding that little kid that run across the street in front of me.
I know you mentioned both, but your stopping power is entirely based on your tires.  Cheap brake pads slow down just as fast as expensive brake pads.  The difference in cheap vs expensive is simply a matter of noise, dust/dirt generated, rotor damage, and pad life.

I don't think anyone in this thread is advocating cheap or bald tires.

lthenderson

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Re: Brake pads
« Reply #7 on: March 07, 2018, 07:31:22 AM »
Cheap brake pads slow down just as fast as expensive brake pads.

Absolutely incorrect statement unless you specifically are comparing brake pads made of the same material. There is a world of difference in stopping power between organic brake pads and metal brake pads because metal creates more friction between the pad and the rotor which is what stops the vehicle. There is also a big difference in cost if you want metallic pads over organic pads.

EricEng

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Re: Brake pads
« Reply #8 on: March 07, 2018, 09:38:47 AM »
Cheap brake pads slow down just as fast as expensive brake pads.

Absolutely incorrect statement unless you specifically are comparing brake pads made of the same material. There is a world of difference in stopping power between organic brake pads and metal brake pads because metal creates more friction between the pad and the rotor which is what stops the vehicle. There is also a big difference in cost if you want metallic pads over organic pads.
Not incorrect.  Any properly functioning brake pad can stop a rotor fast enough to cause a skid and engage the ABS.  Once ABS activates it doesn't matter what type of brake pad you have, your stopping distance is determined solely by the tires coefficient of friction with the ground. 
https://www.roadandtrack.com/car-culture/a10316984/why-braking-is-all-about-tires/
https://auto.howstuffworks.com/auto-parts/brakes/brake-tests/how-to-test-vehicle-stopping-distance1.htm

Edit: Now brake pad marketing will try to convince you otherwise because they need a reason to justify 10 times the cost for their fancy products which are irrelevant to everyday public road drivers. Race track driving, those other factors come into play.
« Last Edit: March 07, 2018, 09:41:00 AM by EricEng »

lthenderson

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Re: Brake pads
« Reply #9 on: March 07, 2018, 12:56:51 PM »
Cheap brake pads slow down just as fast as expensive brake pads.

Absolutely incorrect statement unless you specifically are comparing brake pads made of the same material. There is a world of difference in stopping power between organic brake pads and metal brake pads because metal creates more friction between the pad and the rotor which is what stops the vehicle. There is also a big difference in cost if you want metallic pads over organic pads.
Not incorrect.  Any properly functioning brake pad can stop a rotor fast enough to cause a skid and engage the ABS.  Once ABS activates it doesn't matter what type of brake pad you have, your stopping distance is determined solely by the tires coefficient of friction with the ground. 
https://www.roadandtrack.com/car-culture/a10316984/why-braking-is-all-about-tires/
https://auto.howstuffworks.com/auto-parts/brakes/brake-tests/how-to-test-vehicle-stopping-distance1.htm

Edit: Now brake pad marketing will try to convince you otherwise because they need a reason to justify 10 times the cost for their fancy products which are irrelevant to everyday public road drivers. Race track driving, those other factors come into play.

What about continual breaking situations such as going down mountains? What about heavy load situations where heat build up is a factor? What about vehicles without ABS? There are many situations where ABS is not a factor where brake quality material becomes the major factor. Both those linked articles state that there is a quality difference but that it isn't a factor in one specific situation where you mash on the brakes and ABS takes over. I don't know about you but that comprises less than 1% of my total braking situations.

triangle

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Re: Brake pads
« Reply #10 on: March 07, 2018, 10:18:27 PM »
As another person stated there is too little information to give meaningful feedback. It also depends on your vehicles braking system as I might otherwise not go for ceramic but I would if the manufacturer and rotor recommended them.

Sometimes (or maybe always) lower and lowest priced parts are manufactured in China or elsewhere, where the part may work just as well but the quality control and tolerances are not as stringent. That was my experience recently buying tie-rod ends at my local auto parts store. The left side worked but the right side could not be installed due to being slightly out of spec. The guy at the parts counter was not surprised and said they get a lot of returns on the part.

But as to your specific question I would not have too much problem with the cheapest or nearly the cheapest brake pads. A short test drive will tell you whether they work and that your installation was a success. The force to stop is coming from the hydraulics and power brake booster, where the pad is just a friction material. Unless you are racing or frequently driving on hilly terrain I think it is mostly a question of how long they will last, not whether they will work..

EricEng

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Re: Brake pads
« Reply #11 on: March 08, 2018, 03:25:25 PM »
What about continual breaking situations such as going down mountains? What about heavy load situations where heat build up is a factor? What about vehicles without ABS? There are many situations where ABS is not a factor where brake quality material becomes the major factor. Both those linked articles state that there is a quality difference but that it isn't a factor in one specific situation where you mash on the brakes and ABS takes over. I don't know about you but that comprises less than 1% of my total braking situations.
-Regular cars/vans cruising down the Rockies do fine with cheap pads.  Done this many times.
-Heavy loads is not a factor for normal passenger vehicles.  Nothing I say applies to cargo trucks or race vehicles which endure extreme abuse, I'm talking everyday commuter vehicles.
-All passenger vehicles from the last 20 (30?) years have ABS.  It became mandatory in 2011.  Not that it even matters, pumping the brake manually on cheap vs expensive pads functions the same.

You are ignoring my point.  It doesn't matter if your expensive pads stop the rotor in .5 sec vs 1 sec for cheap pads if your tires still take 10 seconds to slide to a stop.  Your pads always stop far faster than your tires can support.  The bottleneck on stopping isn't your pads, its your traction with the road.  Do your pads help you stop faster in rain and ice?  No, because that is your tires traction which is dominating as it always does. 

If you can trigger ABS, you have exceeded your tires friction and your pads don't matter.  You don't have to trigger ABS, but it just shows in the extreme that your pads are stopping you faster than your tires can.  If you can't ever activate ABS, then your pads are the limiting factor.


Edit: https://blog.caranddriver.com/performance-brake-pads-compared-hawk-hps-hawk-hp-plus-ebc-yellowstuff/
"It’s important to note that upgrading a ­vehicle’s brake pads doesn’t automatically result in shorter stopping distances because performance is ­ultimately limited by available tire grip."
Note their results are all over with a lot of variance and everything is within 10%.  The pads don't matter.
« Last Edit: March 08, 2018, 03:30:33 PM by EricEng »

lthenderson

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Re: Brake pads
« Reply #12 on: March 08, 2018, 04:04:34 PM »
-Regular cars/vans cruising down the Rockies do fine with cheap pads.  Done this many times.

I've seen plenty of cars with smoked organic brake pads at the base of a mountain where I have a vacation home. I also have seen the brakes on the race cars at the local race track and I guarantee their tires have more friction to the racetrack surface than the average car and I have not seen any cheap brake pads there. So we will have to agree to disagree.

EricEng

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Re: Brake pads
« Reply #13 on: March 08, 2018, 05:02:29 PM »
-Regular cars/vans cruising down the Rockies do fine with cheap pads.  Done this many times.

I've seen plenty of cars with smoked organic brake pads at the base of a mountain where I have a vacation home. I also have seen the brakes on the race cars at the local race track and I guarantee their tires have more friction to the racetrack surface than the average car and I have not seen any cheap brake pads there. So we will have to agree to disagree.
-Race cars have expensive pads for different reasons, such as maintaining friction under higher heat, endurance, braking force, etc as I have said and is explained in the links.
-Most people don't cruise down mountains sitting on the brakes.  This isn't a normal use case for 99% of driving commuters see.

I'm still waiting for you to refute my science, show some test data, or explain any faults in my logic.

sequoia

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Re: Brake pads
« Reply #14 on: March 09, 2018, 11:06:57 AM »
Without trying to get into debate if cheap pads works the same as more expensive ones, here is my take:

For MY car: 5000+ lbs SUV + several thousand lbs when towing, last time I did brake job, the difference between cheap vs expensive is $50. I replace pads every 4-5 years, so I am looking at extra $10/year ($20/year for both front and rear pads).

So... assume cheap pads really do work the same, it means I just waste $100 every 5 years - that cost is nothing in my book. Let's assume that the more expensive pad do stopped better - that's money well spent to me.

The risk if cheap pads do not work as good as the expensive one: maybe one day I may ran over a kid running to cross the street, or can not stop in time thus hitting the car in front of me. For extra $100 every 5 years, I sleep better knowing I use the best brake pads. Wife and son are the primary occupants in that SUV, so I probably over-maintained that SUV, and do not cut corners.

triangle

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Re: Brake pads
« Reply #15 on: March 09, 2018, 10:58:59 PM »
Decades ago the main difference between cheap pads and expensive ones were that the expensive ones lasted much longer and some even came with a lifetime warranty. Which might mean the pads are so hard that the rotors wear more than the pads...to which I say no thanks. I would rather buy the cheaper and more rapidly wearing pads to avoid repairing the rotors.

AnonymousCoward

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Re: Brake pads
« Reply #16 on: March 10, 2018, 10:18:10 PM »
I'll jump in in support of EricEng. Tires stop your car. Brakes stop your tires. If your brakes can slow the tires to threshold of the tires breaking traction, then the tires are the limiting factor in how quickly you stop. Modifying the other parts of the braking system can affect brake feel, pedal travel, and response to heat. But not stopping distance.

This article explains this exact point by going over the role of every component of the braking system, from the brake pedal to the master cylinder, brake lines, calipers, brake pads, rotors and tires. https://grassrootsmotorsports.com/articles/grm-vault-grassroots-guide-braking-systems/

EricEng

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Re: Brake pads
« Reply #17 on: March 11, 2018, 10:07:04 PM »
So... assume cheap pads really do work the same, it means I just waste $100 every 5 years - that cost is nothing in my book. Let's assume that the more expensive pad do stopped better - that's money well spent to me.
The cost difference will vary of course if having a shop do it.  https://autoservicecosts.com/brake-pad-replacement-cost/

My issue with that is that the "it's just $10-100 more expensive" logic can be used for every consumable part and thing you put into/on a car.  They cost little different individually so people don't worry about if they are actually getting better quality.  Same thing can be said for many name brand medicines, cleaners, groceries.  While the relative price can be close, just a dollar or two, they can effectively be 40-100% more in cost. 

Thank you pmallory for the great article.  Last page sums up the argument on this one.

sequoia

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Re: Brake pads
« Reply #18 on: March 12, 2018, 12:33:40 AM »
Just sharing personal experience here, and without a scientific data by all means. Replacing brake pads on our SUV (whatever brand it was installed by previous owner with plenty of pad material left) with one of the more expensive after market model sure feels like it stops the car faster. Nothing else was replaced, just brake pads. Again no science data, it is not like my wife make repeated stop from 60-0mph, and me measuring the distance :)

^ are very interesting articles. Since this is MMM, eventually everything comes back to money and cost. So if the cheap pad going to be able to stop the vehicle same distance as expensive pad, is that the recommendation to just buy the cheapest pad but make sure you have a good tires (assuming everything else is in good condition)? While paying extra does not bother me, I am all for saving money, that is why I am here after all.
« Last Edit: March 12, 2018, 12:38:34 AM by sequoia »

EricEng

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Re: Brake pads
« Reply #19 on: March 12, 2018, 09:09:55 AM »
Just sharing personal experience here, and without a scientific data by all means. Replacing brake pads on our SUV (whatever brand it was installed by previous owner with plenty of pad material left) with one of the more expensive after market model sure feels like it stops the car faster. Nothing else was replaced, just brake pads. Again no science data, it is not like my wife make repeated stop from 60-0mph, and me measuring the distance :)
Can't say for certain, but it could have been switching from an organic, soft squishy brake pad to a firmer metal or ceramic type.  That would result in more braking force from less force on the brake pedal.  So while you still stop as fast potentially, it will feel faster because you aren't having to smash the brake nearly as hard.  Did they also bleed the brake lines or replace the fluid?  That can affect the responsiveness of it as well which will also cause this.  My parents car reminds me of this, I barely brush the brakes and it nearly locks the wheels.

lthenderson

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Re: Brake pads
« Reply #20 on: March 12, 2018, 05:11:18 PM »

...cars have expensive pads for different reasons, such as maintaining friction under higher heat, endurance, braking force, etc

...switching from an organic, soft squishy brake pad to a firmer metal or ceramic type.  That would result in more braking force from less force on the brake pedal.

I'm still waiting for you to refute my science, show some test data, or explain any faults in my logic.

I have not once debated that when you engage ABS, that the tires are the deciding factor in stopping distance. I'm in agreement with you on that issue. However, I have said this constitutes a very small percentage of my braking and thus is irrelevant to me. What is relevant to me and what I have said, it that brake pads materials make a difference in maintaining friction under higher heat, endurance and braking force necessary to stop which is exactly what you admitted to above.

sequoia

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Re: Brake pads
« Reply #21 on: March 12, 2018, 05:39:23 PM »
Just sharing personal experience here, and without a scientific data by all means. Replacing brake pads on our SUV (whatever brand it was installed by previous owner with plenty of pad material left) with one of the more expensive after market model sure feels like it stops the car faster. Nothing else was replaced, just brake pads. Again no science data, it is not like my wife make repeated stop from 60-0mph, and me measuring the distance :)
Can't say for certain, but it could have been switching from an organic, soft squishy brake pad to a firmer metal or ceramic type.  That would result in more braking force from less force on the brake pedal.  So while you still stop as fast potentially, it will feel faster because you aren't having to smash the brake nearly as hard.  Did they also bleed the brake lines or replace the fluid?  That can affect the responsiveness of it as well which will also cause this.  My parents car reminds me of this, I barely brush the brakes and it nearly locks the wheels.

It was me who did the work, so I know nothing else was touched - no bleeding the lines or replacing the fluid. I wanted to replace just one thing to see if how much does the expensive pad made a difference. Hey I paid extra $, I better see some improvement here :)
 
That make sense re: switching from organic to metal/ceramic. Thank you!

Clean Shaven

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Re: Brake pads
« Reply #22 on: March 12, 2018, 08:34:33 PM »
Similar to what Eric said, new pads are thicker and reduce the amount of brake pedal travel before the brakes engage.  So pushing the brake pedal one inch does a lot more with new pads.  Not having to press down as far does impact your reaction time a bit.
This isn't how automobile hydraulic brakes work. They self adjust so that the pads are the same distance from the rotor whether new or used. This is why you have to force the pistons back into the calipers when changing old pads for new - the old thin pads have the pistons pushed far out, but the new thick pads require the pistons to be seated back into their bores.

I agree with Eric's assessment of braking and pads as well. For a passenger vehicle on street, pretty much any regular pad is fine and will stop safely and in about the same distance as any other pad. This all goes out the window if you're talking about repeated high heat braking (track).

EricEng

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Re: Brake pads
« Reply #23 on: March 13, 2018, 08:19:42 AM »
I have not once debated that when you engage ABS, that the tires are the deciding factor in stopping distance. I'm in agreement with you on that issue. However, I have said this constitutes a very small percentage of my braking and thus is irrelevant to me. What is relevant to me and what I have said, it that brake pads materials make a difference in maintaining friction under higher heat, endurance and braking force necessary to stop which is exactly what you admitted to above.
I bring up ABS to prove which limit you are hitting first.  If your brake pads are unable to stop the wheels/rotors faster than your tires on the road can stop as you claim, then your ABS will never engage no matter how hard you press and your argument would be valid.  If your ABS activates at any point, your break pads have stopped faster than your tires will allow and my argument is valid.  It does not matter if you don't normally break to the point of ABS engaging (hopefully no one does), this is just a way to prove which bottleneck you are encountering first.

Ultimately your brake pads, even cheap ones, will still be stopping the rotor faster than your tires can even in ideal conditions, dry road with good friction.  Please review pmallory's link that goes into the science on this if you are still confused:
https://grassrootsmotorsports.com/articles/grm-vault-grassroots-guide-braking-systems/

lthenderson

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Re: Brake pads
« Reply #24 on: March 13, 2018, 09:20:22 AM »
I have not once debated that when you engage ABS, that the tires are the deciding factor in stopping distance. I'm in agreement with you on that issue. However, I have said this constitutes a very small percentage of my braking and thus is irrelevant to me. What is relevant to me and what I have said, it that brake pads materials make a difference in maintaining friction under higher heat, endurance and braking force necessary to stop which is exactly what you admitted to above.
I bring up ABS to prove which limit you are hitting first.  If your brake pads are unable to stop the wheels/rotors faster than your tires on the road can stop as you claim, then your ABS will never engage no matter how hard you press and your argument would be valid.  If your ABS activates at any point, your break pads have stopped faster than your tires will allow and my argument is valid.  It does not matter if you don't normally break to the point of ABS engaging (hopefully no one does), this is just a way to prove which bottleneck you are encountering first.

You seem to have a reading comprehension problem. Please re-read the bold text.

EricEng

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Re: Brake pads
« Reply #25 on: March 14, 2018, 09:51:04 AM »
You seem to have a reading comprehension problem. Please re-read the bold text.
And you seem to be failing to read my post where I go on to explain that the ABS case is applicable for all cases, even when ABS does not engage.  I have given many explanations and and scientific math behind why this applies 100% of the time, yet you keep cherry picking the ABS part and ignoring everything else.  The ABS is a simplified example.

You state you aren't engaging ABS, so it does not apply.  That does not make logical sense.  If your brake pads were limiting you more than your tires (before ABS) as you claim, then you could never reach the point of engaging ABS to begin with.  You have to refute that logic before you can claim your point valid.  "Friction under higher heat, endurance, and braking force" are  irrelevant for normal driving outside race tracks and cargo hauling.  If those are the only use cases you care about then we are having two different conversations.

lthenderson

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Re: Brake pads
« Reply #26 on: March 14, 2018, 04:39:53 PM »
If your brake pads were limiting you more than your tires (before ABS) as you claim, then you could never reach the point of engaging ABS to begin with.  You have to refute that logic before you can claim your point valid.  "Friction under higher heat, endurance, and braking force" are  irrelevant for normal driving outside race tracks and cargo hauling.  If those are the only use cases you care about then we are having two different conversations.

The coefficient of friction for brake pads range from a mu of 0.3 on the cheap side to 0.45 on the performance side to 0.6 on the racing side. So if brake pressures (N) are the same, then the stopping force of the brake increases (F=mu*N) with the higher coefficient of the brake pad which costs more money. Now you claim that it doesn't matter when the coefficient of friction between the tires and the roads is the limiting factor. According to many sources, the coefficient of friction between a dry surface and the average tire is 0.7. So if you do the calculations, brakes play a tremendous role in stopping the car up until the point where the tire starts slipping which is where the ABS kicks in and prevents said tire from slipping to maintain the 0.7 (or maximum) amount of friction as possible to start. How can you claim that the higher value of F applied to slowing down tire rotation isn't braking you sooner as long as the tire isn't slipping? Are arguing that a mu of 0.3 on the low end and 0.6 on the high end provide the same force at the tire? All those linked articles you quote as your evidence essentially are stating the case when your ABS is engaged. As I stated before, I can count the number of times my ABS has kicked in on one hand because I don't brake that hard which means the limiting coefficient of friction for stopping distance on my vehicle is the brake pad.  The reason brake pads are designed to have less friction than tires is to prevent you from going into an instant skid the moment your brakes engage.

Then you also discount wear in all your arguments. Wear is an important factor in many people's average sedans and to get better wear characteristics, one must go with more expensive materials in brake pads. I mentioned driving in routinely mountainous environments and your only proof that brake fade (google it if you don't understand the concept) doesn't exist is that you drove down a mountain in a van once just fine. Brake fade in cheaper pads occurs much sooner than more expensive pads with metallic or ceramic materials.

Cheap brake pads may work for some but your statement that there is no difference between cheap and more expensive brake pads is absolutely false. There are many differences of which I have pointed out two. So please continue to refute this by telling me about your links referring to the situation when ABS has kicked in.

triangle

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Re: Brake pads
« Reply #27 on: March 14, 2018, 11:21:20 PM »
Certainly everyone is free to buy the pads they think are best for their pocketbook and needs. I don't think spec sheets or performance tests matter that much because the information is not available in an easy to understand format and is subject to interpretation. And tires, driving conditions, driver behavior, etc play such an important role.

Personally I do not want poor quality pads, such as having bad workmanship or being out of spec, but as long as the drivers reaction time is good then a higher price does not necessarily lead to a meaningful decrease in stopping distance in my opinion (I certainly have no way to prove or disprove this belief even to myself). Longer life pads may be a wise economic choice for the person living in a place where labor charges are high. But I am of the opinion that longer lasting pads place more wear on the rotor, so when it comes time to change the pads the total repair bill may be greater since the rotor is more likely to need attention. Cars are long past the days of using inferior drum brakes that fade and wear out quickly. The disc brake pads which replaced them, even the ones which wear out fairly quickly are more than enough to stop the vehicle.

Bottom line outside all this debate, one only needs to get the minimally spec pad that the manufacturer recommends. Since it is a braking system, where the size of the rotor, tires, vehicle purpose are factors. 

EricEng

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Re: Brake pads
« Reply #28 on: March 15, 2018, 08:47:36 AM »
The coefficient of friction for brake pads range from a mu of 0.3 on the cheap side to 0.45 on the performance side to 0.6 on the racing side. So if brake pressures (N) are the same, then the stopping force of the brake increases (F=mu*N) with the higher coefficient of the brake pad which costs more money. Now you claim that it doesn't matter when the coefficient of friction between the tires and the roads is the limiting factor. According to many sources, the coefficient of friction between a dry surface and the average tire is 0.7. So if you do the calculations, brakes play a tremendous role in stopping the car up until the point where the tire starts slipping which is where the ABS kicks in and prevents said tire from slipping to maintain the 0.7 (or maximum) amount of friction as possible to start. How can you claim that the higher value of F applied to slowing down tire rotation isn't braking you sooner as long as the tire isn't slipping? Are arguing that a mu of 0.3 on the low end and 0.6 on the high end provide the same force at the tire? All those linked articles you quote as your evidence essentially are stating the case when your ABS is engaged.
You neglect a couple key factors.
1.  It does not matter if one has a higher coefficient of friction as they are in very different contexts.  IE, imagine friction of .1 with 1000 lbs of pressure vs .7 friction with 10 lbs of friction.  Coefficient friction alone means nothing.
2.  More importantly, brake forces don't need to be the same as you you state because you can apply more force (ie press brake pedal harder) to compensate (something I acknowledged earlier).  Your car however can not apply more downward force on the tires to the roads, so the force is fixed.  This plays into how touchy or soft your brakes may feel, but we are assuming the driver with leverage from the pedal can apply adequate force.
3.  Your friction math changes when you consider cars don't get the full downward force on the rear tires as the momentum pushes it forward.  Same reason a front brake/tire on a motorcycle has over double the stopping ability of the back brake/tire.
4.  You need to review the math in the article we linked: https://grassrootsmotorsports.com/articles/grm-vault-grassroots-guide-braking-systems/
 
As I stated before, I can count the number of times my ABS has kicked in on one hand because I don't brake that hard which means the limiting coefficient of friction for stopping distance on my vehicle is the brake pad.  The reason brake pads are designed to have less friction than tires is to prevent you from going into an instant skid the moment your brakes engage.
So much wrong here.  If that was true, you would have never been able to activate the ABS at any point.
The limiting factor before abs is simply your choice of force being applied to the brake pedal. Some gets lost to slipping at the brake pad and some gets lost to your tire slipping on the road.  However, you have the ability to apply more force to the pedal which gets translated into friction force from pad against the rotor which slows/stops the wheels.  You have the ability, in theory, to apply enough force to the pedal to instantly stop the rotors (poor car)...which would of course cause you to skid or abs because the tires can't hold the road that fast.  The limit is how much force you apply to the pedal in that case.  The next limit is your tires friction.

Yes, if you had a pad with a coefficient of friction equivalent of ice you would likely have issues applying enough force, but that isn't the case.

Then you also discount wear in all your arguments. Wear is an important factor in many people's average sedans and to get better wear characteristics, one must go with more expensive materials in brake pads. I mentioned driving in routinely mountainous environments and your only proof that brake fade (google it if you don't understand the concept) doesn't exist is that you drove down a mountain in a van once just fine. Brake fade in cheaper pads occurs much sooner than more expensive pads with metallic or ceramic materials.

Cheap brake pads may work for some but your statement that there is no difference between cheap and more expensive brake pads is absolutely false. There are many differences of which I have pointed out two. So please continue to refute this by telling me about your links referring to the situation when ABS has kicked in.
Our discussion up until this point was on stopping distance from a safety standpoint. 
The cheap brake pads from Autozone come with lifetime warranty that you can replace for free.  Pretty hard to beat that value if you are worried about wear.  Organic will of course wear the fastest, but least damage to your rotor.  Ceramic have less of the force you love, but also easier on the rotors.  It's all trade off, but I haven't seen anything to show cheap pads wearing through faster than expensive of the same style.  I did acknowledge early on that cheap metal pads will possibly eat your rotors faster.

http://www.atlautosports.com/ceramic-vs-metallic-brake-pads/
« Last Edit: March 15, 2018, 09:04:47 AM by EricEng »

lthenderson

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Re: Brake pads
« Reply #29 on: March 15, 2018, 09:06:44 AM »
Our discussion up until this point was on stopping distance from a safety standpoint.

I'll repeat this for the fourth or fifth time, "stopping distance from a safety standpoint" has been your discussion from the beginning not mine. I rarely panic stop. My "discussion" has been that provided that your tires have adequate traction, me pressing on the brakes pads with the same amount of force will provide a shorter stopping distance with pads with a higher coefficient of friction. See the equation F=mu*N. If N remains the same (i.e. the force I apply onto the pads using the brake pedal) and mu changes depending on the quality of the brake pad, F or the force slowing down the car also changes.

I haven't seen anything to show cheap pads wearing through faster than expensive of the same style

Again, from the third paragraph of the very article you linked "Metallic pads ... are harder and more durable"

EricEng

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Re: Brake pads
« Reply #30 on: March 15, 2018, 12:29:35 PM »
Our discussion up until this point was on stopping distance from a safety standpoint.

I'll repeat this for the fourth or fifth time, "stopping distance from a safety standpoint" has been your discussion from the beginning not mine. I rarely panic stop. My "discussion" has been that provided that your tires have adequate traction, me pressing on the brakes pads with the same amount of force will provide a shorter stopping distance with pads with a higher coefficient of friction. See the equation F=mu*N. If N remains the same (i.e. the force I apply onto the pads using the brake pedal) and mu changes depending on the quality of the brake pad, F or the force slowing down the car also changes.
Did you skip over point 2 where I addressed this?  Your pedal force/distance of travel can be increased to accommodate the lower brake pad friction while maintaining the same stopping distance. Yes, if you apply the exact same brake pedal force with a different coefficient friction brake pad or tire you will get a different stop distance.  If your priority is heavy stopping power with only the lightest feathering of the pedal, then yes you will have an issue with all but the most premium of pads.

That said, this isn't even an issue in modern normal cars because they have braking assist to ensure adequate force is applied regardless of how much actual force you apply.  This means your argument about force at the pedal is pointless because pedal force is not directly translated to braking force that the car applies.  The electronic braking assist will add force as needed.
https://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/brake-assist1.htm
http://www.toyota-global.com/innovation/safety_technology/safety_technology/technology_file/active/brake.html

Side note you are neglecting is the fact that a lot of these pads have different friction levels at different temperatures.  The expensive ones meant for track and heavy abuse stick better at higher temp while cheap (like metallic) stick better at lower temp which is more likely for regular driving.
I haven't seen anything to show cheap pads wearing through faster than expensive of the same style

Again, from the third paragraph of the very article you linked "Metallic pads ... are harder and more durable"
You failed to read again.  I said expensive vs cheap of the same style. Semi-Metallic pads from autozone are the cheap ones I had in mind.  That said, you can get organic, semi metallic, or ceramic from Autozone for $20-25 with the same warranty, so your preference at that point.

Clean Shaven

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Re: Brake pads
« Reply #31 on: March 15, 2018, 01:30:53 PM »
a lot of these pads have different friction levels at different temperatures.  The expensive ones meant for track and heavy abuse stick better at higher temp while cheap (like metallic) stick better at lower temp which is more likely for regular driving.

^^^ This is an important point for the home mechanic looking to replace brake pads.  Don't be tempted by flashy advertising about race brakes or some such stuff.  You may end up with a car that stops worse (regular driving, not track use), has noisy brakes, and produces a lot of brake dust.

And I'll add, for anyone doing their own brake work at home:  don't bother with slotted rotors -- or even worse, drilled rotors.  You won't gain anything in braking on your daily driver.

lthenderson

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Re: Brake pads
« Reply #32 on: March 16, 2018, 01:34:43 PM »
Yes, if you apply the exact same brake pedal force with a different coefficient friction brake pad or tire you will get a different stop distance. 

To sum up this discussion, you made a blanket statement that all pads, expensive down to the cheap were the same and I called you out on that statement. It took all this discussion for you to finally admit that there is a difference in brake pads.

thesis

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Re: Brake pads
« Reply #33 on: April 05, 2018, 08:20:01 AM »
When I got my first car, and before I learned how to do most of the work myself, one shop fleeced me good and sold me new front brake pads, front rotor resurfacing, new hardware, new rear brake shoes. I'm pretty sure they sold something else with that, maybe not as extreme as the drums. Oh, and a brake flush. Anyway, it cost me a ton, but since these were "important" changes, I bit the bullet, because who wants to smash into another vehicle because you can't stop? Most of this was just psychology. F--- that shop. I was young and dumb and ignorant about cars.

In my experience, the brake itself doesn't squeak, it all comes down to how well you grease the parts and whether you grease them in the right places. It has been mind blowing to me that everyone kind of has their own approach. I like duralast gold pads just because they have a shim already glued on (granted, most do) and it comes with the brackets the pads "slide" on. Dirty brackets get rusty and squeak more often. Whenever my pads have squeaked, a little more brake grease on those slide brackets, or usually just the parts of the brakes the fit in there, and a little around where the brake piston touches has done the trick. My friend is a mechanic and puts the absolute cheapest brake pads on his car, but he also knows how to get away with things like that :)

Easye418

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Re: Brake pads
« Reply #34 on: April 06, 2018, 09:55:12 AM »
Check out Rockauto, I always get my brake pads and rotors from there and have my independent mechanic install them for me.  He usually charges me pretty small labor charge to do it at my house. 

I usually go with customer favorites or the middle tier pair. 

PrairieBeardstache

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Re: Brake pads
« Reply #35 on: April 06, 2018, 03:04:27 PM »
I didn't read all of the back-and-forth but it's Friday and I'm cruising...

Also checking in to support Eric's point.

Source: I raced cars semi-competitively for ten years in a discipline where tires, brakes, and suspension mattered more for car setup than anything else.

A driver on the street will never need the capabilities of a higher performance pad. Those are all about heat management and what the pad does when heated. You'll never see those temps on the street and any driver can lock their tires on the street by applying enough force with any street pad. As Eric says, the limiting factor is the tires, not the pad.

Fun Fact: I didn't read the entire post but an above poster was mentioning the coefficient of friction of tires and pads and also mentioned ABS. A *good* driver can out-brake ABS. We did it quite often and our dataloggers showed when we messed up and ABS engaged. In the classes we were running we weren't allowed to disable it, this is often done in more modified classes.

sokoloff

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Re: Brake pads
« Reply #36 on: April 06, 2018, 03:20:56 PM »
Check out Rockauto, I always get my brake pads and rotors from there and have my independent mechanic install them for me.  He usually charges me pretty small labor charge to do it at my house.
Love and second RockAuto.

Always google for a "rockauto discount code". They're a short string of letters that are good for a certain amount of time, so find a recent one (so maybe google "Rockauto discount code April 2018" or something). Paste it into the box "How did you hear about us?" and you'll get a 5% discount [on most things].

They'll mail you your own discount code about 30 days after your order, which is where the code you got off some random forum post comes from.

BlueMR2

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Re: Brake pads
« Reply #37 on: April 06, 2018, 05:12:54 PM »
I've become a fan of ceramic for general purpose use.  I used to always just use carbon Kevlar pads so I was always ready for the track, but those were stupid expensive.  One thing I've learned the hard way is to always use OEM support hardware (shims, etc) as the aftermarket stuff never quite fits right and leads to rubbing/squealing.