Warped Rotor debate

[Littleguy]

My knowledge is pretty minimal compared to others here but, I would think that with a metal rotor and a ceramic pad the heat resistance in the pad would be greater than the rotor. This makes me think that it is the rotors actually being warped, not the pad.

[ansonivan]

Here's my understanding:

 

- pad material deposited unevenly on the rotor*

- the rotor heats unevenly because of the deposits

- the rotor warps

 

* pad deposits could be caused by a slightly warped rotor... chicken or the egg here

[nurkvinny]

OP, have you personally ever held warped rotors in your own hands? Hundreds of times? Visually inspected them with your own eyes? That had every imaginable pad material? From tons of different manufacturers?

 

Have you personally ever machined a rotor? Hundreds of times?

 

Have you personally went to school for this topic? Even looked at an ASE test?

 

Nobody is arguing that pads can't cause a "warped" feel. We all get that. But, your refusal to accept a known cause of warping is, well, hard-headed. It's obvious you enjoy a good debate, and that's cool, but again, I'll stick to the idea that a combined 100? 125? 150? years of actual real-world auto repair > you reading on the internet.

[Qtr_pndr]

so looking at his theory must also go along with heads must be gasket material melted on that makes you think it is warped. I am going to go with the heat theory I have seen lots of warped rotors, also all that stoptech is telling you is what they have seen have you ever personally saw it no you are to busy swinging from their testicles licking their ass to realize you have no clue what you are saying. Edited July 18, 2010 by Qtr_pndr

[V8 Beast]

Going from a scientific stand point how much heat and or pressure would it take to alter the shape of metal? Can brakes pads and the heat caused by stopping a car produce enough heat and pressure to warp a perfectly shaped rotor?

[AJ]

please reread the artical from stop tech. did you notice its written by one person and not posted as a company? so thats what one person says.

 

do rotors warp from heat? yes

 

can i prove it? yes, bring your car over and i will heat up half the rotor with a torch and then you go drive it and tell me what happens.

 

can rotors warp from pad transfer? yes.

 

can i prove it? yes, when you bring your can over to test the other part we will drive around with the brake on untill the rotors turn glowing red. at the point we will stop and sit there while holding the brakes so part of the pad melts to the rotor. when it cools down we will drive and then you can tell me what happens.

 

do you have enough background in this field to have this debate? no. OMG its on the internet it must be true!!

[AJ]

Can brakes pads and the heat caused by stopping a car produce enough heat and pressure to warp a perfectly shaped rotor?

 

yes.

[spooling 1g]

Can brakes pads and the heat caused by stopping a car produce enough heat and pressure to warp a perfectly shaped rotor?

 

Would it really be the pressure??Or just the cooling affects of the material warping the rotor??

[AJ]

Would it really be the pressure??Or just the cooling affects of the material warping the rotor??

 

depends, if the slides are stuck then between the heat and pressure they can warp a rotor.

[Habitual Sinner]

If the rotors just have pad composites on then to appear to be warped, the rotor would be thicker in some places than others.

 

All three times that I have replaced warped rotors, thay were the same thickness all the way around.

 

Heat causes metal to flex/expand.

 

/thread.

[Crossle]

Excess heat....go back roading.

 

Also, if it were adding material to the rotors, how come they get thinner over their useful life? There are minimal thickness specifications that tell us if they are too thin to lathe because thinner metal cannot dissipate the heat as well as thicker rotors.

 

Some rotors are manufacturer defect...warped straight out of the box.

 

Sometimes it's due to rust or corrosion built up on the hub b/w the rotor. Hence why you sand/take a wire brush to the hub when you do brakes.

 

Sometimes pulsation could be a pitted rotor, rust has physically taken chunks out of the rotor over time.

 

Never heard of pads causing a pulsation, the rotor is a rotating surface, the pad wears and the rotor wears.

[V8 Beast]

What I'm getting at is its something that typically happens over time. Doing a burn out for 5 minutes in 3rd gear or stopping hard from 150mph (or using a torch ) can do it but most people dont drive their car that hard. For the typical driver I would have to assume manufacturer defects and cheap materials are mostly to blame.

[TA In Progress]

My post in V8 Beast's thread sparked some opinions on this that differed from my own.

 

My statement: Warped rotors are caused by pad material being fused to the rotor causing an uneven rotor surface. This causes the pedal to pulsate. This is commonly referred to as a warped rotor.

 

Their statement: A warped rotor is the disk metal itself bending from excess heat.

 

My evidence: http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

 

Discuss

 

If you had ever turned a set of rotors (or drums) on a brake lathe, you wouldn't be arguing this. Explain this: You have set of rotors on a brake lathe and can actually watch the ventilation channel (where the fins are) move side to side. Is the pad material that you say is deposited on the pad surface of the rotor creating this optical illusion?

[jeffro]

rotors warp.

[Dave1647545494]

hopefully derek(turbo rust) will post up a picture I saw a pad today that had part of the rotor melted to it it was pretty cool

[,,,,,,comma,,,,,,]

u pull it sel roters

[Berto]

Rotors warp but most people won't get rotors hot enough to warp them.

 

I personally believe that warping/pulsating brakes that most people encounter is due to simple rotor exposure to water. Notice every time you walk to your car after its rained (and has been parked), its already rusted. However, behind the pads where it stayed dry there is no rust. After a few hundred/thousand cycles of this you will end up with high/low spots due to the fact that the rust if removed the first time you brake.

 

I got this theory from a brake guy I worked with at Honda, and it makes sense. Ever since I have garaged my cars every night i have never had warped rotors. My civic has 85k miles and the brakes are straight as can be.

[TurboRust]

Rotors warp but most people won't get rotors hot enough to warp them.

it all comes from driving styles.. I get tons of idiots come through ntb with warped rotors, leave with new and come back in 6 months with the same issue. some people just suck at driving.

[xlr8tn]

please reread the artical from stop tech. did you notice its written by one person and not posted as a company? so thats what one person says.

 

do rotors warp from heat? yes

 

can i prove it? yes, bring your car over and i will heat up half the rotor with a torch and then you go drive it and tell me what happens.

 

can rotors warp from pad transfer? yes.

 

can i prove it? yes, when you bring your can over to test the other part we will drive around with the brake on untill the rotors turn glowing red. at the point we will stop and sit there while holding the brakes so part of the pad melts to the rotor. when it cools down we will drive and then you can tell me what happens.

 

do you have enough background in this field to have this debate? no. OMG its on the internet it must be true!!

 

IMO that statement right there shoots holes all through the extra material on the rotor being the reason. Metal can and does warp from excessive heat...rotors are no exception. It doesn't mean that what he's saying isn't possible because I guess I kinda see where he's coming from but it can't explain a brand new rotor being warped after it's been hit with a torch.

[JaSSon]

Rotors warp but most people won't get rotors hot enough to warp them.

 

1 emergency stop is enough to warp rotors. I've had to get on the brakes hard on my old stang on the free way before and then noticed a pulsation. 1 rapid heating/cooling cycle is enough to warp (especially cheap) metal.

 

The cheap Chinese rotors that are widely available aren't helping the situation.

 

do rotors warp from heat? yes

 

can i prove it? yes, bring your car over and i will heat up half the rotor with a torch and then you go drive it and tell me what happens.

 

can rotors warp from pad transfer? yes.

 

can i prove it? yes, when you bring your can over to test the other part we will drive around with the brake on untill the rotors turn glowing red. at the point we will stop and sit there while holding the brakes so part of the pad melts to the rotor. when it cools down we will drive and then you can tell me what happens.

 

This. Aaron, if you're so hard headed that you won't listen to anyone's arguments, then step up and do some testing of your own. Take AJ up on his offer to apply flame to your brakes.

[TA In Progress]

The cheap Chinese rotors that are widely available aren't helping the situation.

 

Very true.

[HAOLE]

Would it really be the pressure??Or just the cooling affects of the material warping the rotor??

 

From my experience working in machine shops, excessive heat then cooling will cause steel to change shape. That is just one of the reason colant is used in most machining process.

 

IMHO rotors warp from the heat/cool cycle and also based on the material used in the rotor. If you by cheap Chinese made rotors that use inferior steel they will tolerate less heat than good quality rotors.

[SinisterSS]

can we get a poll?

[FormulaMatt]

which is cheaper for Honda? Turn the rotors? or replace the pads?

 

Money could be the reasoning behind their bulletin.

 

So you are saying that one of the largest brake manufacturers, and race suppliers overlooked your simplistic argument? Think about what YOU are saying.

 

Your own argument applies here too.

[Aaron]

Do I have enough "experience" to have this debate? Probably not.

 

I believe this article. I believe that pads melt onto the rotors.

 

I also have heard that excess heat, and improper lug nut tq causes the rotors to warp.

 

Do I have any scientific proof of either? No

 

Do you guys? None has been presented. Not 1 picture, nothing but opinions as of now.

 

Contrary to what some of my posts might have implied, I do believe that heat, improper tq and pad transfer are ALL responsible for warped rotors. I should have never said definitively that rotors don't warp from heat. It was not what I was trying to propose. If that is the source of all of this, then it is my fault. I simply wanted a discussion on the matter.

 

I won't lie, I do and will continue to believe that pad transfer contributes to the majority of warped rotors until a picture, or personal evidence is provided. You guys can call it hard headedness or me retarded all you want. Is it really a big deal that I expect more than personal testimonials as my proof?

 

The front rotors on my GTI were warped. I will be taking them down to o'reileys sometime this week to see what we come up with. I will take pictures and post my findings.

 

Almost everybody in here needs a few beers or some alone time with lotion asap. Its a discussion, grow up.

Edited July 19, 2010 by Aaron