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#16
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That is your opinion.
However, it is the opinion of Carroll Smith, a guy who knows more than you or I, that : "In fact every case of "warped brake disc" that I have investigated, whether on a racing car or a street car, has turned out to be friction pad material transferred unevenly to the surface of the disc.* This uneven deposition results in thickness variation (TV) or run-out due to hot spotting that occurred at elevated temperatures." I'm going to side with the professional car guy who's been into racing and high performance cars his entire life. |
#17
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Funny thing is... "Coning" is a form of warping.
I don't doubt that guy has a lot of knowledge under his belt, but it doesn't mean he's 100% correct in his explanation. I do believe him that many cases are misdiagnosed as warping, but anything that distorts the physical dimensions of an object is causing it to warp. Also, the FIGURE 3 example is another form of warping. He's using very technical terms and masking the more "popular" descriptor.
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Eddie '92 SVX LS-L (For Sale! Info and link to pics... ) #9536 blt. 4/92 (late boomer '92) '01 Audi S4 (2.7L Twin Turbo - 6MT) |
#18
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Yes, but basically, if you buy pads that are designed for really high temperatures, they will not transfer pad material very easily, hence you will probably not get a pedal vibration.
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#19
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Lateral Runout (LRO). LRO occurs when two axes are not parallel to each other, such as the axes of the rotor and the hub or the spindle and the rotor/hub. LRO may be caused by manufacturing tolerances, improperly torqued wheel nuts (uneven or excessive torque), corrosion between the brake rotor and the hub, hub with excessive runout, worn or improperly adjusted wheel bearings or any damage or wear. This is what is commonly referred to as "warped" rotors. These so called "warped" rotors do not in and of themselves cause the vibrations and pulsations. Any machined component, such as brake rotors and hubs, are going to have manufacturing tolerances, which include runout. Typical original equipment new rotor runout specifications are in the range of 0.0015-0.002 in. while low quality aftermarket rotors can be significantly higher. In addition to excessive manufacturing tolerances, cheap, low quality aftermarket rotors can have increased impurities and porosity in the metallurgy.
What can occur over a period of time is that whatever runout is in the system coupled with improperly torqued wheel nuts and/or misadjusted or loose wheel bearings and rust and corrosion forming between the rotor and hub surface leads to increases in runout. As you drive your vehicle without using the brakes, such as on the highway, every rotation of the rotor high spot or multiple high spots contacts your brake linings in the caliper, even when you are not using the brakes and wears the high spot or multiple high spots off the rotor which causes a thin spot or multiple thin spots. Over a period of time this repeated process causes what is called Disc Thickness Variation (DTV). DTV is when the rotor thickness is not the same all the way around the rotor. DTV is typically caused by lateral runout. DTV can only be measured with very specialized laboratory testing equipment or with special on vehicle capacitance probes. When you apply your brakes, and a brake rotor has DTV, the thick and thin spots on the rotor cause the brake pads to move in and out. This in-and-out pad motion causes increases and decreases in brake system pressure, which the driver can feel in the brake pedal. This in-and-out pad motion causes a varying brake force, which is passed to the steering wheel. As the rotor gets hot, it is much more likely to increase thickness variation, thus increasing pedal pulsations as well as steering wheel and other vehicle vibrations. This phenomenon is what many technicians refer to as "warping", however they actually think the rotor warped and needs replacement. --> Brought to you by Detroit, Michigan Truck and Automotive Engineers and Lubrication Specialists. We have over 19 years experience engineering cars and trucks right here in the heart of the car and truck engineering and manufacturing capital of the world and we will put our extensive knowledge to use for you. We are also longstanding Professional Grade members of the Society of Automotive Engineers (SAE). This prestigious position is ONLY granted to degreed engineers with documented work experience in the automotive engineering industry.
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Matt Locker Link 2015 BRZ Limited 6MT 92 Ebony LS-L ECUtune Stage2av1, Z32 MAF, 370cc injectors, TomsSVX intake, BontragerWorks 22mm RSB #003, HID Hi and Lo beams, OT endlink and bushing mods, PWR Aluminum radiator, Harvey's QC shift kit, 2.5" flowmaster 80 exhaust, 17" Michelin Pilot Sport A/S, Poly sway bar bushings, Slotted Bradi rotors, AFBeefcake powdercoated calipers, 97 grill, and a huge set of air horns. 300,000 miles and counting 92 Ebony LS-L. ecutune stage1v4, motorsport 1pc pulley. Garage Queen - sold to Dad in upstate NY 155,000 miles 19 Subaru Ascent Premium - -Hers !. 89 DL 4x4 little red wagon - a.k.a. The immortal suby. 275k R.I.P. |
#20
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Quote:
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Matt Locker Link 2015 BRZ Limited 6MT 92 Ebony LS-L ECUtune Stage2av1, Z32 MAF, 370cc injectors, TomsSVX intake, BontragerWorks 22mm RSB #003, HID Hi and Lo beams, OT endlink and bushing mods, PWR Aluminum radiator, Harvey's QC shift kit, 2.5" flowmaster 80 exhaust, 17" Michelin Pilot Sport A/S, Poly sway bar bushings, Slotted Bradi rotors, AFBeefcake powdercoated calipers, 97 grill, and a huge set of air horns. 300,000 miles and counting 92 Ebony LS-L. ecutune stage1v4, motorsport 1pc pulley. Garage Queen - sold to Dad in upstate NY 155,000 miles 19 Subaru Ascent Premium - -Hers !. 89 DL 4x4 little red wagon - a.k.a. The immortal suby. 275k R.I.P. |
#21
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Warping has to do with uneven heat and cooling so the object 'warps' as it cools. |
#22
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Believe whomever you'd like, but after switching to good pads, even after tons of pretty impressive stops I have NO warping what-so-ever. - Jim |
#23
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I'm not saying good pads aren't a great thing to have, but they simply are not going to eliminate brake warping.
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Matt Locker Link 2015 BRZ Limited 6MT 92 Ebony LS-L ECUtune Stage2av1, Z32 MAF, 370cc injectors, TomsSVX intake, BontragerWorks 22mm RSB #003, HID Hi and Lo beams, OT endlink and bushing mods, PWR Aluminum radiator, Harvey's QC shift kit, 2.5" flowmaster 80 exhaust, 17" Michelin Pilot Sport A/S, Poly sway bar bushings, Slotted Bradi rotors, AFBeefcake powdercoated calipers, 97 grill, and a huge set of air horns. 300,000 miles and counting 92 Ebony LS-L. ecutune stage1v4, motorsport 1pc pulley. Garage Queen - sold to Dad in upstate NY 155,000 miles 19 Subaru Ascent Premium - -Hers !. 89 DL 4x4 little red wagon - a.k.a. The immortal suby. 275k R.I.P. |
#24
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In fact, just for kicks, I went to dictionary.com and pulled a better description: warp ( P ) Pronunciation Key (wôrp) v. warped, warp·ing, warps v. tr. To turn or twist (wood, for example) out of shape. To turn from a correct or proper course; deflect. To affect unfavorably, unfairly, or wrongly; bias. See Synonyms at bias. To arrange (strands of yarn or thread) so that they run lengthwise in weaving. Nautical. To move (a vessel) by hauling on a line that is fastened to or around a piling, anchor, or pier. v. intr. To become bent or twisted out of shape: The wooden frame warped in the humidity. To turn aside from a true, correct, or natural course; go astray. See Synonyms at distort. Nautical. To move a vessel by hauling on a line that is fastened to or around a piling, anchor, or pier. n. The state of being twisted or bent out of shape. A distortion or twist, especially in a piece of wood. A mental or moral twist, aberration, or deviation. The threads that run lengthwise in a woven fabric, crossed at right angles to the woof. Warp and woof. Nautical. A towline used in warping a vessel. In conclusion...Any change in the physical dimensions and variations in the shape of an object (in this case, a brake rotor) is considered to be warping.
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Eddie '92 SVX LS-L (For Sale! Info and link to pics... ) #9536 blt. 4/92 (late boomer '92) '01 Audi S4 (2.7L Twin Turbo - 6MT) |
#25
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You are incorrect. A rotor is made out of cast iron. How do you WARP cast iron? If I took a sledgehammer to your SVX's hood, would I be warping it? No. If I took a blowtorch and applied the flame to one end and caused it to buckle a little would I be warping it? Yes.
I had store raybestos pads in my SVX a while back.... after a few months they developed some uneven pad desposits. With the axxis pads, I have none, and my brakes feel incredible. |
#26
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#27
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[QUOTE]Originally posted by marlettpat
[QUOTE] FATS - Foreign Auto and Truck Supply The place to be if you have a boxer. Quote:
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"That which can be asserted without evidence can be dismissed without evidence." '92 Dark Teal SVX LS-L, >146,000m 3 pedals, 5 speeds., restoration underway. 2012 Honda Insight, slow but cute. |
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