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Possible warped rotors

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Old Sep 22, 2010, 03:30 PM
  #16  
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Originally Posted by WarmPepsi
Yup. A pulse or "shake" is a high spot on the rotor that slows down more due to more friction between the pad and the rotor face. The high spot is pad transfer. When turning them.. you have a flat face again.

If you were actually warping them, after a turn or two, it would get DRAMATICALLY worse, as you'd have a lot of uneven metal left on the rotors that would expand and contract at different rates..
Word up guys. I just got some pads from O'reiley's. I think they are actually carbon/metallic it says on the box.
http://www.oreillyauto.com/site/c/de...0068&ppt=C0009
not bad looking, they have that layer of metal on the back end to stop heat transfer. I just hope they aren't loud. I had some hawk HP + and every time I backed up I had horrible brake noise. Gotta be better than the ones I have now.
Old Sep 26, 2010, 11:02 AM
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Feel the surface of the rotors (when they are cool!) if they are bumpy and uneven you need new rotors or can have them recut.
Old Sep 26, 2010, 11:24 AM
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Originally Posted by 01 Trans-Am WS6
Feel the surface of the rotors (when they are cool!) if they are bumpy and uneven you need new rotors or can have them recut.
This weekend I pulled the rotors off and felt them. I could actually feel the uneveness when feeling in a circle (not the ridges caused by uneven wear).

I took the rotors to a machine shop and was going to assemble the whole thing with freshly turned rotors and new pads, but..... the guy called me back and told me the rears were less than minimum allowance and the fronts were at the minimum and could not be turned. Basically they're trash..... sucks.

So, I ordered some new rotors from girodisc today, the one piece directional vane ones, but I don't think the rears are directional though. What are your guy's thoughts on girodisc? They look pretty good online, but I have never dealt with their stuff in person. I also called around to local auto-parts stores and could have gotten some rotors for like $70-120/each but I figured they must be crap at that price, and stock replacement brembo rotors were like $800 and not worth it. I could get 2-piece ones for that price.
Old Sep 26, 2010, 12:17 PM
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rotor pros . net is what i've used on the rears... used them on track, no issues. got blanks, not drilled/dimpled/slotted. The only thing slots do is clear the pad to make it flat (read: eats pads quicker).

Last edited by WarmPepsi; Sep 26, 2010 at 12:20 PM. Reason: wow... didn't know we were censored here on the forum... guess i'll pm you the company i'm talking about... n/m, got it.
Old Sep 26, 2010, 05:52 PM
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Originally Posted by steadly2004
This weekend I pulled the rotors off and felt them. I could actually feel the uneveness when feeling in a circle (not the ridges caused by uneven wear).

I took the rotors to a machine shop and was going to assemble the whole thing with freshly turned rotors and new pads, but..... the guy called me back and told me the rears were less than minimum allowance and the fronts were at the minimum and could not be turned. Basically they're trash..... sucks.

So, I ordered some new rotors from girodisc today, the one piece directional vane ones, but I don't think the rears are directional though. What are your guy's thoughts on girodisc? They look pretty good online, but I have never dealt with their stuff in person. I also called around to local auto-parts stores and could have gotten some rotors for like $70-120/each but I figured they must be crap at that price, and stock replacement brembo rotors were like $800 and not worth it. I could get 2-piece ones for that price.
never buy cheap rotors from an auto parts store unless name brand cause you get what you pay also not all auto parts store know how to store them, and they will warp and not last once over heated will become good as garbage.
Old Sep 26, 2010, 05:57 PM
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..you guys... don't get it... any of the major brake manufacturers will tell you the same thing... you have hot spots, and pad buildup... the rotor itself is NOT WARPED... If i can't warp them on track, with BLACKENED calipers.. you sure as hell aren't toasting them on the streets.
Old Sep 27, 2010, 08:43 PM
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Originally Posted by WarmPepsi
..you guys... don't get it... any of the major brake manufacturers will tell you the same thing... you have hot spots, and pad buildup... the rotor itself is NOT WARPED... If i can't warp them on track, with BLACKENED calipers.. you sure as hell aren't toasting them on the streets.
I got what you are saying make senses to me. but cheap rotor you will wrap cheap rotor metal is thinner and low quality material being use, hint cheap rotors but i totally get what you are saying. but i have seen rotor wrap when you turn them you will see the rotor uneven turning on the brake lathe.
Old Sep 28, 2010, 04:57 AM
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Originally Posted by MRolla
I got what you are saying make senses to me. but cheap rotor you will wrap cheap rotor metal is thinner and low quality material being use, hint cheap rotors but i totally get what you are saying. but i have seen rotor wrap when you turn them you will see the rotor uneven turning on the brake lathe.
This is a part fallacy. The metal is not thinner. They are made the same way Brembo or other expensive rotors are. Metal material might be less pure as others. But many of use have found no big difference under heavy useage.

Most of it comes down to pad choice and braking technique (over braking any pad will cause you issues). Using a pad that is too hard (like a higher MOT race pad) on the street will give you issues with rotor wear and noises. Or inversely a pad that does not have a proper MOT for track use will cause the pad to melt off under heavy use - where do you think that material is going to go?
Old Sep 28, 2010, 02:46 PM
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Originally Posted by SmikeEvo
This is a part fallacy. The metal is not thinner. They are made the same way Brembo or other expensive rotors are. Metal material might be less pure as others. But many of use have found no big difference under heavy useage.

Most of it comes down to pad choice and braking technique (over braking any pad will cause you issues). Using a pad that is too hard (like a higher MOT race pad) on the street will give you issues with rotor wear and noises. Or inversely a pad that does not have a proper MOT for track use will cause the pad to melt off under heavy use - where do you think that material is going to go?
I think I have posi-quiets or something like that and was running it hard one day, like 120+ (I don't condone this on the street by any means) and it started wobbling with the heavy breaking.

Most likely was using too much of a daily driver street pad, and using it too aggressively.
Old Oct 1, 2010, 08:21 AM
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Steadly,
I did an article and video on choosing pads, swapping pads to avoid judder/vibration, bedding-in, etc. Check them out on our site. They may help you properly manage your brakes and avoid future issues.
Old Oct 1, 2010, 08:31 AM
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Smikevo is rt-- you went the rt way on getting the slotted rotors. The slots will help rid you of excess pad material ( dust) and therefore you wont get the build up. good set of pads are needed as well--now I didnt say expensive just good. We have all had the same issue-- with the slotted rotors I haven't had a single problem after I got them--40k ago. DD and tracked--no pops , no clicks, no noise no shudder.
Old Oct 3, 2010, 01:56 PM
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Originally Posted by JRitt@essex
Steadly,
I did an article and video on choosing pads, swapping pads to avoid judder/vibration, bedding-in, etc. Check them out on our site. They may help you properly manage your brakes and avoid future issues.
Fantastic informative video! Very awesome and absolutely will affect my future brake adventures. Haven't put the new rotors/pads on yet, but I will soon enough and will be doing a good bed-in procedure. I figure the only place I can go fast/slow and repeat will be on the freeway, and it's the only place I can manage not to come to a complete stop when I want that layer to cool down.
Old Oct 10, 2010, 07:40 AM
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Originally Posted by JRitt@essex
Steadly,
I did an article and video on choosing pads, swapping pads to avoid judder/vibration, bedding-in, etc. Check them out on our site. They may help you properly manage your brakes and avoid future issues.
SO, I just installed the performance friction pads and girodisc directional vane rotors.

I went on the highway and did my stops from about 80mph to 30-35mph or so. During stop 2 and 3 I got a really good burning smell. The brakes started gripping more and more, and about run 8 or 9 it got really stout. (actually the same pedal pressure chirped the tires) I thought I was supposed to continue doing pulls until it stopped improving and gets spongy. But, it just kept getting better and better. I just let it be at that point and drove without braking for like 10 min for a good cool down.

The cold bite seemed to remain the same, so I guess bedding in doesn't really help with cold bite, but the warmed up braking probably doubled according to my "butt dyno."

Last edited by steadly2004; Oct 10, 2010 at 07:44 AM.
Old Oct 10, 2010, 09:33 AM
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You are doing the final burnish on the pad material.

8 to 10 bedding stops and then a through cool off is all that is needed. Not running the temps to the point of fluid boil.
Old Oct 10, 2010, 09:58 AM
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i have the same problem but in my case my rotors are new and so are my brakes sooo what else can cause it to shake??


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