Is it common for new brake rotors to warp?
- Thread starter grampi
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I had alot of problems with my OEM rotors on my Silverado. Had to have them turned at 13,000 miles because they were so bad and they warped again within 20,000 miles.
Replaced with Powerslot and have not had a problem since. Currently have 28,000 miles on them and the dealer service manager even came out to ask me where I purchased them and the brand because he wanted to put them on his 2005 Silverado. He explained to me it was common and that mine still looked brand new.
Replaced with Powerslot and have not had a problem since. Currently have 28,000 miles on them and the dealer service manager even came out to ask me where I purchased them and the brand because he wanted to put them on his 2005 Silverado. He explained to me it was common and that mine still looked brand new.
Follow all the links to the stoptech articles above.
Then dig in some more.
They are fantastic and well worth it.
This guy says he almost never sees a truly warped rotor, but deposits cause bad feel and operation, and contribute [if left alone for a while] to actual metal rotor anomalies.
He is huge on break in for brakes. He wants that pad film/deposit correctly deposited on the rotor.
And a few good hard stops from 60 to 30 in a row fixes many problems.
Then dig in some more.
They are fantastic and well worth it.
This guy says he almost never sees a truly warped rotor, but deposits cause bad feel and operation, and contribute [if left alone for a while] to actual metal rotor anomalies.
He is huge on break in for brakes. He wants that pad film/deposit correctly deposited on the rotor.
And a few good hard stops from 60 to 30 in a row fixes many problems.
Did you lube your caliper slides? That tends to keep rotor warping at bay.
Originally Posted By: SteveSRT8
Iron is iron.
May want to check this link
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
Rotors are very rarely warped.
I am a mechanical engineer with a degree from a school that is so brutal that it takes 10 years for graduates to forget how hard it was and start to be grateful for all the good stuff they learned.
And I disagree with the above post, and the Stoptech "Thechnical Info".
1. "Iron" is NOT "Iron". Without going into excruciating detail, I will point out that the two most common types of cast iron (virtually all brake rotors are made from cast iron) are "Gray Iron" and "Ductile Iron". The latter is stronger and more durable--it responds better to fatigue--and is generally more expensive.
2. I read the StopTech article and "The Physics of Braking Sytems" by James Walker, Jr.(who?). My conclusion is that these people may know how to make good high performance brake parts for certain market segments (although I find their specific claims hard to verify), but they are clueless about vehicle dynamics, heat transfer, friction, internall stresses, creep, vector mechanics, and even physics. Don't trust their comments in these areas. There is a reason that car mfrs hire massive heaps of engineers (NOT Master Technicians) to develop cars.
Recommended for study: "Physics: An Incremental Development"
http://www.amazon.com/Physics-Incremental-Development-Saxon/dp/1565770056
Stoptech just wants to sell parts.
Iron is iron.
May want to check this link
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
Rotors are very rarely warped.
I am a mechanical engineer with a degree from a school that is so brutal that it takes 10 years for graduates to forget how hard it was and start to be grateful for all the good stuff they learned.
And I disagree with the above post, and the Stoptech "Thechnical Info".
1. "Iron" is NOT "Iron". Without going into excruciating detail, I will point out that the two most common types of cast iron (virtually all brake rotors are made from cast iron) are "Gray Iron" and "Ductile Iron". The latter is stronger and more durable--it responds better to fatigue--and is generally more expensive.
2. I read the StopTech article and "The Physics of Braking Sytems" by James Walker, Jr.(who?). My conclusion is that these people may know how to make good high performance brake parts for certain market segments (although I find their specific claims hard to verify), but they are clueless about vehicle dynamics, heat transfer, friction, internall stresses, creep, vector mechanics, and even physics. Don't trust their comments in these areas. There is a reason that car mfrs hire massive heaps of engineers (NOT Master Technicians) to develop cars.
Recommended for study: "Physics: An Incremental Development"
http://www.amazon.com/Physics-Incremental-Development-Saxon/dp/1565770056
Stoptech just wants to sell parts.
Originally Posted By: grampi
Originally Posted By: Michael_P
Just put new NAPA premium rotors on my truck.......Made in China.
It's difficult to buy ANYTHING these days that's not made in china :0(
I just bought two Raybestos Advanced Technology rotors and was fully expecting them to be made in China. I was somewhat shocked when I saw "Made in USA" stamped on the boxes.
Originally Posted By: Michael_P
Just put new NAPA premium rotors on my truck.......Made in China.
It's difficult to buy ANYTHING these days that's not made in china :0(
I just bought two Raybestos Advanced Technology rotors and was fully expecting them to be made in China. I was somewhat shocked when I saw "Made in USA" stamped on the boxes.
Cast iron is tricky to do well. Cheap rotors will warp very quickly because they are made of inferior iron. If your car starts to shudder when you use your brakes on a harder-than-average stop, you need to rip those sorry things off and get something better.
Don't skimp on brakes. Please.
Don't skimp on brakes. Please.
grampi,
If I were you I would remove what you have and install some top-shelf Raybestos, Wagner, or Brembo (if available for your car) disks and pads.
Don't skimp on brakes.
If I were you I would remove what you have and install some top-shelf Raybestos, Wagner, or Brembo (if available for your car) disks and pads.
Don't skimp on brakes.
Originally Posted By: Kaboomba
I am a mechanical engineer with a degree from a school that is so brutal that it takes 10 years for graduates to forget how hard it was and start to be grateful for all the good stuff they learned.
And I disagree with the above post, and the Stoptech "Thechnical Info".
Stoptech just wants to sell parts.
Good for you. But I live in the real world and not in a physics book.
Note that my brother in law runs a 3rd gen machine shop. He has some commercial contracts with local law enforcement. On a good week he may see 60 (sixty!) rotors for turning. Around 30 or so is typical.
We tracked his work for a full month and were only able to find ONE ROTOR that was really warped. Every other one machined had pad deposits on the surface that were caused by pads sitting clamped on hot rotors.
I had never even heard of Stoptech before 2005. But they are only one of many inputs into my decision making process. Their info on rotors and bedding have saved me thousands this year alone on brakes, as we have too many vehicles in our fleet!
You are free to believe what you want. But all the theoretical physics in the classroom have mislead you on this issue.
I am a mechanical engineer with a degree from a school that is so brutal that it takes 10 years for graduates to forget how hard it was and start to be grateful for all the good stuff they learned.
And I disagree with the above post, and the Stoptech "Thechnical Info".
Stoptech just wants to sell parts.
Good for you. But I live in the real world and not in a physics book.
Note that my brother in law runs a 3rd gen machine shop. He has some commercial contracts with local law enforcement. On a good week he may see 60 (sixty!) rotors for turning. Around 30 or so is typical.
We tracked his work for a full month and were only able to find ONE ROTOR that was really warped. Every other one machined had pad deposits on the surface that were caused by pads sitting clamped on hot rotors.
I had never even heard of Stoptech before 2005. But they are only one of many inputs into my decision making process. Their info on rotors and bedding have saved me thousands this year alone on brakes, as we have too many vehicles in our fleet!
You are free to believe what you want. But all the theoretical physics in the classroom have mislead you on this issue.
Most warped rotors are a case of non-uniform thickness of the rotor around the circumference and not true warping. A friend of mine (auto shop teacher at Boces) put cheap a rotor on one side and an expensive rotor on the other side (front) and in a year they both looked equally [censored]. His conclusion is that most rotors are pretty [censored] and many rust from the inside out.
I recommend cheap rotors and the best pads that you can find.
There are no guarantees with expensive rotors.
After working on umpteen jillion brakes, basically cast iron is cast iron.
Clean them, torque the wheels down with a torque wrench, and bed the pads in right. Of course the calipers have to be smooth and lubed.
What has happened is that China gets a bad rap because the advent of their output on items like this coincided with the downsizing of brake systems. They run much hotter than before and more problems occur.
There are no guarantees with expensive rotors.
After working on umpteen jillion brakes, basically cast iron is cast iron.
Clean them, torque the wheels down with a torque wrench, and bed the pads in right. Of course the calipers have to be smooth and lubed.
What has happened is that China gets a bad rap because the advent of their output on items like this coincided with the downsizing of brake systems. They run much hotter than before and more problems occur.
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thanks for that. Those of us who wrench for a living know a wee bit about brakes.
X2 on the best pads you can afford.
X2 on the best pads you can afford.
Originally Posted By: Michael_P
Just put new NAPA premium rotors on my truck.......Made in China.
Are there any brake rotors made in USA anymore?
Just put new NAPA premium rotors on my truck.......Made in China.
Are there any brake rotors made in USA anymore?
Brembos for my '02 Camaro used to be made in Canada, but are now made in Mexico. That particular application has massive problems with warped front rotors. I endured warped rotors for a long time while production was moved to go with cryo Brembos.
My work trucks use massive rotors, and I've gone with the cheap Chinese rotors on those. We'll see how they hold up.
The problem with Chinese parts is that quality control is very spotty. If they don't have a probability of full inspection, the manufacturing shop managers will try every trick in the book to cut costs. Everything from using sub-standard steel to loostening the specs for a finished product. You take your chances with anything coming from China.
My work trucks use massive rotors, and I've gone with the cheap Chinese rotors on those. We'll see how they hold up.
The problem with Chinese parts is that quality control is very spotty. If they don't have a probability of full inspection, the manufacturing shop managers will try every trick in the book to cut costs. Everything from using sub-standard steel to loostening the specs for a finished product. You take your chances with anything coming from China.
To be sold as brake rotors, certain parameters are supposed to be achieved concerning the metal content, by US law.
My thinking is that expensive rotors are simply not a sure thing, esp with fancy slotted and drilled ones - all sorts of problems can occur, and do occur.
My thinking is that expensive rotors are simply not a sure thing, esp with fancy slotted and drilled ones - all sorts of problems can occur, and do occur.
Originally Posted By: SteveSRT8
Originally Posted By: Kaboomba
I am a mechanical engineer with a degree from a school that is so brutal that it takes 10 years for graduates to forget how hard it was and start to be grateful for all the good stuff they learned.
And I disagree with the above post, and the Stoptech "Thechnical Info".
Stoptech just wants to sell parts.
Good for you. But I live in the real world and not in a physics book.
Note that my brother in law runs a 3rd gen machine shop. He has some commercial contracts with local law enforcement. On a good week he may see 60 (sixty!) rotors for turning. Around 30 or so is typical.
We tracked his work for a full month and were only able to find ONE ROTOR that was really warped. Every other one machined had pad deposits on the surface that were caused by pads sitting clamped on hot rotors.
I had never even heard of Stoptech before 2005. But they are only one of many inputs into my decision making process. Their info on rotors and bedding have saved me thousands this year alone on brakes, as we have too many vehicles in our fleet!
You are free to believe what you want. But all the theoretical physics in the classroom have mislead you on this issue.
My point is that Stoptech is wrong up on things that are so basic that they can be refuted in high school physics books.
If you don't trust high school physics books...you probably wear a foil hat, deny the Apollo moon landings, and frequently go to the chiropractor to help the neck pain you get from looking for black helicopters.
I would like to see you design and build a brake rotor (not even a brake system), starting with dirt, done in less than 75 years, without using any books or physics or classroom training.
Originally Posted By: Kaboomba
I am a mechanical engineer with a degree from a school that is so brutal that it takes 10 years for graduates to forget how hard it was and start to be grateful for all the good stuff they learned.
And I disagree with the above post, and the Stoptech "Thechnical Info".
Stoptech just wants to sell parts.
Good for you. But I live in the real world and not in a physics book.
Note that my brother in law runs a 3rd gen machine shop. He has some commercial contracts with local law enforcement. On a good week he may see 60 (sixty!) rotors for turning. Around 30 or so is typical.
We tracked his work for a full month and were only able to find ONE ROTOR that was really warped. Every other one machined had pad deposits on the surface that were caused by pads sitting clamped on hot rotors.
I had never even heard of Stoptech before 2005. But they are only one of many inputs into my decision making process. Their info on rotors and bedding have saved me thousands this year alone on brakes, as we have too many vehicles in our fleet!
You are free to believe what you want. But all the theoretical physics in the classroom have mislead you on this issue.
My point is that Stoptech is wrong up on things that are so basic that they can be refuted in high school physics books.
If you don't trust high school physics books...you probably wear a foil hat, deny the Apollo moon landings, and frequently go to the chiropractor to help the neck pain you get from looking for black helicopters.
I would like to see you design and build a brake rotor (not even a brake system), starting with dirt, done in less than 75 years, without using any books or physics or classroom training.
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Kabooma - I did not scrutinize all the stoptech articles, but they seemed great -at least certainly a valuable perspective.
Can you point out for us the "wrong up on things" that are there?
Can you point out for us the "wrong up on things" that are there?
Sorry for goofed up grammar in previous post.
A few things about the "Myth..." article:
1. In the article, the word "runout" is used. "Runout" which is greater after the rotor has been used than when the rotor was in the box is what we're calling "warp" on this forum.
2. Warping is the dimensional change of the rotor. There are three basic ways this can happen. Heat (causing expansion, cooling causing contraction, not always in nice ways), stress/strain, material added to the rotor (from the pads, presumably). The picture shown to illustrate the latter (material deposition on the surface of the rotor) shows patchy spots of pad deposits. The only way deposits could appear that way is due to localized dimensional variation (loss of flatness in this case) and/or localized superheating of the rotor (which coincides with loss of flatness--heat-related dimensional changes again). I have also seen pictures of rotors with deposits which were consistent all the way around the friction surface. They were from racing projects. I can't think of anyone I know who has had any type of pad deposits on their passenger car or truck rotors. I am not denying it could happen with some rotor and pad combinations on someone's vehicle, just that it's universal.
3. The article completely ignores the effects of braking forces on the disk itself. It's complicated, and I would want to run FEA simulations and tests to fully understand the effects (perhaps they are thinking of racing hardware, which may differ greatly from on-road applications). As the iron rotor gets hot, it wants to succumb more to the massive squeezing and pulling forces coming from the calipers and pads. One effect of a long, severe stop with a bargain-basement passenger car rotor made of low grade iron would be the slight "spreading" or "stretching out" of the friction surface, some of which might stick around after the event is over. What's left is a friction surface that has a few thousanths of "wiggle" and thickness variation, maybe only enough for 1-3 variations per rotation.
4. One effect of the "squeezing and pulling" could be stress relieving, in the case of rotors made from lower-grade gray iron castings. It's conceivable that rotors turned from castings that were too small to begin with (not enough material cut away from the raw casting) would leave rotor surfaces with inconsitant microstructures which would behave differently when subjected to heat and stress.
5. Warped brake rotors aren't a myth. Lots of rotors warp. Mine have warped in the past. I know lots of people who have experienced warped rotors, and I have driven their cars and observed the effect. On one of my own vehicles, the warped rotor caused the steering weel to twitch at very low speed. I removed the rotors. While removing them I observed perfectly clean, bright gray iron. I also saw that when I spun them on the hub, they rubbed the pads the way my bike rims used to rub my brake pads after I crashed into a curb!
The following is an excellent resource for understanding passenger brake rotors in depth--pages 60-88 are probably most useful:
http://www.sae.org/events/bce/tutorial-ihm.pdf
K
A few things about the "Myth..." article:
1. In the article, the word "runout" is used. "Runout" which is greater after the rotor has been used than when the rotor was in the box is what we're calling "warp" on this forum.
2. Warping is the dimensional change of the rotor. There are three basic ways this can happen. Heat (causing expansion, cooling causing contraction, not always in nice ways), stress/strain, material added to the rotor (from the pads, presumably). The picture shown to illustrate the latter (material deposition on the surface of the rotor) shows patchy spots of pad deposits. The only way deposits could appear that way is due to localized dimensional variation (loss of flatness in this case) and/or localized superheating of the rotor (which coincides with loss of flatness--heat-related dimensional changes again). I have also seen pictures of rotors with deposits which were consistent all the way around the friction surface. They were from racing projects. I can't think of anyone I know who has had any type of pad deposits on their passenger car or truck rotors. I am not denying it could happen with some rotor and pad combinations on someone's vehicle, just that it's universal.
3. The article completely ignores the effects of braking forces on the disk itself. It's complicated, and I would want to run FEA simulations and tests to fully understand the effects (perhaps they are thinking of racing hardware, which may differ greatly from on-road applications). As the iron rotor gets hot, it wants to succumb more to the massive squeezing and pulling forces coming from the calipers and pads. One effect of a long, severe stop with a bargain-basement passenger car rotor made of low grade iron would be the slight "spreading" or "stretching out" of the friction surface, some of which might stick around after the event is over. What's left is a friction surface that has a few thousanths of "wiggle" and thickness variation, maybe only enough for 1-3 variations per rotation.
4. One effect of the "squeezing and pulling" could be stress relieving, in the case of rotors made from lower-grade gray iron castings. It's conceivable that rotors turned from castings that were too small to begin with (not enough material cut away from the raw casting) would leave rotor surfaces with inconsitant microstructures which would behave differently when subjected to heat and stress.
5. Warped brake rotors aren't a myth. Lots of rotors warp. Mine have warped in the past. I know lots of people who have experienced warped rotors, and I have driven their cars and observed the effect. On one of my own vehicles, the warped rotor caused the steering weel to twitch at very low speed. I removed the rotors. While removing them I observed perfectly clean, bright gray iron. I also saw that when I spun them on the hub, they rubbed the pads the way my bike rims used to rub my brake pads after I crashed into a curb!
The following is an excellent resource for understanding passenger brake rotors in depth--pages 60-88 are probably most useful:
http://www.sae.org/events/bce/tutorial-ihm.pdf
K
just in the last couple of weeks, i took out the 03 TL-S, and really gave it a run, around some turns, WOT runs, just to clean it out, and by i was at like the 3rd turn, i hit the brakes and they were warped.... Really? They were fine for 69K miles, and then just out of the blue, now the car shakes when slowing down... SO i really got them good and hot, then jumped on the highway for a little to let them cool, when i was done, the vibration when braking was 95% gone.. and has not come back, just under normal braking...
The first article linked to the Stoptech site was written by Carrol Smith of Ford GT40 fame.
http://en.wikipedia.org/wiki/Carroll_Smith
http://www.carrollsmith.com/main.html
http://en.wikipedia.org/wiki/Carroll_Smith
http://www.carrollsmith.com/main.html
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