Warped rotor pics.

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3,992
Location
Central Maryland
Originally Posted by Trav
Originally Posted by HangFire
I don't see any debate here , about the rotors anyway. People quoting the real racing brake expert engineer's paper and trying to make it say something it doesn't, then others using that as a straw man, I do see. Re-read the stoptech article carefully and see if there's really anything to disagree with. I'll tell you something that's no myth, service writers blaming owners for warping rotors, while having no runout measurements to base it on. Caught in the act, several times, by me. Proven wrong, with my instruments. So yeah I get a gold star, not a participation trophy.
You don't see any debate because you don't have the experience other than what you read on the net.
I don't see any debate IN THIS THREAD... as for the rest, I'll just ignore your crass and ignorant insult. For those who are interested in what the real expert said, stoptech.com took down the article, but here's a copy of it. http://ipgparts.com/blog/stoptech-puts-to-rest-many-brake-myths/ And with that, I'm out.
 
Messages
6,773
Location
Fort Lauderdale, FL
Never had a warped rotor in my life. Had trailer brakes give out during a hard stop on a 12 ton load. Still didn't warp rotors. Had to drive 7 miles with my brakes self-applying on the same rotors due to a bad hydraulic booster. Still didn't warp them. Brake lathe does not lie, but origins are still questionable.
 
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28,129
Location
Regina, Saskatchewan, Canada
I would suggest it's possible that you might have had discs that handled such abuse a little better or had a more foolproof geometry. You can well imagine how taxis get driven, and I've never seen warped discs (or pad deposits or whatever we want to call it) on the old Caprice or Crown Vic platforms. Other vehicles haven't been so fortunate.
 
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6,773
Location
Fort Lauderdale, FL
I hear you. It's a valid point. But my position is that I've owned multiple types and brands of vehicles over the years. I've used everything from eBay brake rotors, to Brembos, to OEM, to exotic racing brands, etc. I've beaten the daylights out of almost all of them. I've left a set of rotors with hairline cracks working their way through the entire face. I've left rotors with bluing through the hat. I buy new rotors because the old ones are no longer capable of being saved. Either below minimum thickness or in no shape to be reused. They do all last me a really long time, however. But I have absolutely never had warped rotors. Ever. But somehow people are warping their rotors while going to out to run errands and get groceries? It's just really hard for me grasp. It's easy to put a rotor in a lathe and see what it looks like now. Not so easy to see what it was like in the beginning. I really get the feeling a lot of rotor warpage occurs on the manufacturing level.
 
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6,688
Location
California
Originally Posted by DoubleWasp
I really get the feeling a lot of rotor warpage occurs on the manufacturing level.
Shipping and storage too. A lot of brake rotors get stacked on shipping containers and it's advised to keep them flat, but many warehouses and parts stores will store rotors vertically on their shelves. Probably gets worse with drums, due to the obvious.
 
Messages
3,992
Location
Central Maryland
Originally Posted by nthach
Originally Posted by DoubleWasp
I really get the feeling a lot of rotor warpage occurs on the manufacturing level.
Shipping and storage too. A lot of brake rotors get stacked on shipping containers and it's advised to keep them flat, but many warehouses and parts stores will store rotors vertically on their shelves. Probably gets worse with drums, due to the obvious.
No, just no to all this causing warpage. Peenage in shipping, sure.
 
Messages
28,129
Location
Regina, Saskatchewan, Canada
Originally Posted by DoubleWasp
But I have absolutely never had warped rotors. Ever. But somehow people are warping their rotors while going to out to run errands and get groceries? It's just really hard for me grasp.
With all the stories we hear, it's obviously not always warping. There certainly are cases here of bad deposits and other causes to runout. The G37 had a runout problem of some sort, which might have been pad deposits, since once it was cured by a bed in procedure, and later on, though, it wasn't. The taxis, my LTD, my trucks, my Town Car, and the Audi never gave me any runout issues, whatever the cause.
 
Messages
1,599
Location
Watertown, New York
I've been through oem dealer training that stated something along the lines of "rotors don't warp, the pulsation is caused by pad deposits", my friend attended a NAPA brake class, and they were preaching the same narrative. It is amazing to me that big players in the industry are preaching this! Anyone that has run a brake lathe on a semi regular basis has seen something similar to the OP's pics. While I have definitely seen many that did have excess run out due to pad deposits, it is still fairly common to see a warped rotor.
 
Messages
2,377
Location
pa
most rotors being cast in China are ok at best, you can get a bad new one + surely can warp one in use. a pulsating brake pedal on lighter braking quickly tells the story. of course there can be other issues, as always everything needs to be checked.
 
Messages
23,761
Location
MA, Mittelfranken.de
Theory and reality are 2 completely different things. The problem lies in the verbiage, the term "warp" has been used for decades by mechanics worldwide when it comes to describing distortion of the disc regardless of how or why it happened the end result is the same a disc that is not true. Metallic brakes can grind softer spots away on the disc causing the harder areas to worn less and result in a distorted disc, did it warp like a piece of overheated sheet metal? No but it is distorted nevertheless. Ditto for installing the disc out of run out spec, sticking caliper slides and mounts where the piston side pad wears faster that the other, poor wheel torque methods, etc. All can cause distortion which is commonly referred to as warping. Maybe we should appease the paper pushers and start using the word " distorted" instead which they admit does exist.
Quote
Brake rotors provide a friction surface for the disc brake pads to rub against when the brakes are applied. ... Uneven rotor wear (which may be due to excessive rotor runout or rotor distortion) often produces variations in thickness that can be felt as pedal pulsations when the brakes are applied
 
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Messages
6,773
Location
Fort Lauderdale, FL
Didn't mean to be a "paper pusher". Was honestly trying to resolve how I; an arguably abusive driver and previous purchaser of cheap Asian rotors, had never encountered this problem. The information you posted adds up. I always do my own brakes, and always use quality heavy duty pads, and always grease everything and use new shims and other new hardware. Wheels always torqued in progressive star pattern. This would place me outside of the possibility of encountering distortion due to incompetent practices.
 
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Messages
23,761
Location
MA, Mittelfranken.de
That was not aimed at you or any poster here DoubleWasp but the articles written on this subject. Some people believe that if you heat a rotor it will end up like a Tostitos, that is not true. When I worked in fleet situation we ran into this a lot for a long time, the pads were very aggressive and had a high metal content even by Euro standards, the rotors would get torn up quickly and brake pulsation would occur. There was no question about it being pad deposits, there wasn't much rotor left. There was no question about the installation either yet it kept happening. It turned out the rotors being provided to us were not compatible with the pads (ATE or Textar), once we started running high carbon content disc the rotors still wore but not to the extent they once did and not many complaints of "warping", the later BMW 3 series cars did not have many issues. Based on this experience I can only conclude that brake disc quality also plays a role when it comes to brake rotor distortion depending on the pads used.
 
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