I just warped a second set of stock frt rotors on the 996. I believe I have original pads, which appear to be sintered metal and GG designation. I understand HH would have more grip and more heat, possibly exacerbating the problem. Aside from carbon/silicon carbide discs what can stave this off in future? I bought a new replacement set of the Brembo snowflake rotors (not stainless) for reasonable and had a plan to service the old ones by using full floaters and having the disc blanchard ground. .006" warpage on disc itself, no run-out on the carrier. That is on hold though. I am inclined to just put the new discs on but thought I would use an organic pad of some sort.
I read I should be not be running sintered w steel or iron disc. Do the SBS dual carbon with the 'transfer film' work on the street or are they dangerously ineffective till hot? Fire away folks, Thanks for your consideration in this mater .
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When smashing monuments, save the pedestals. They always come in handy. Stanislaw Lem
Stainless snowflakes as stock on 996 models like the sintered pads. The older ductile iron full floating brembo rotors do not like sintered. Newer stainless brembo HP rotors like the sintered.
If you have any disc/pad pairing questions, Fred at Yoyodyne is intimately familar with all the Brembo products from the last 30 years or so, and also has performance friction pads for the fitments that they are better suited to.
Are the discs discolored? Make sure everything is working correctly in your brake system as well, the snowflakes shouldn't warp overly easily, especially on the street. It could be that something is misaligned, corroded, or just hanging up a bit.
I am not sure that I would say they warped easy, the originals and their replacements lasted ~15k mi. , and Mt Palomar is close by. Semi-floaters, no discoloring, and I saw somewhere that the early snowflakes were prone to cracking. Probably why they were warrantied no questions asked. I brought in only the rotors. Did not note the originals material but looked like the warranty ones and my new ones. These 2 sets are not stainless. I think steel.
Good idea about asking Fred. I think these came from him though I purchased thru Cycle Brakes. I did not know that he had them until ordered, and she said they had to come from NJ, price was identical to Yoyodyne also. I think I talked w him briefly the other day about his axles. He was helpful.
Thanks, I may just look again on the website for the pad recommend before calling. I am sure he can say what these discs are made of if I do not see it.
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When smashing monuments, save the pedestals. They always come in handy. Stanislaw Lem
I seem to have conflated a couple of responses, CC, I took your suggestion and called Fred and he confirmed what I see you saying, namely the snowflake rotor is stainless. He felt the original pads were organic. Admittedly a lot of metal in them though. I may just run the same combination and scuff the old pads. Thanks again, R
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When smashing monuments, save the pedestals. They always come in handy. Stanislaw Lem
They probably were semi-metallic / semi-organic or whatever they're calling it these days. Full metallic / fully sintered pads are generally HH. Plus the semi-metallic pads are quieter, so they might have been trying to avoid complaints from the street riders. Or it could just be that 1999 was just before full-sintered HH pads became de riguer on sport bikes.
Looking at the problem of warpage in SS purely from a metallurgical perspective:
SS always has a lot of retained stress in it. From the rolling mill, the blanking operation, the laser cut/machining/water jetting, grinding etc. Heating this slab of alloy from usage of the brakes allows 'some' of the stresses to be released whereas the material wants to return to it's pre machined state, or dimensions hence we see warpage.
For what it's worth, a lot of manufacturers in many industries that use SS especially in a thin cross section such as a brake rotor miss an important manufacturing step.
The parts are blanked and machined. Then, the unfinished disc should be subjected to what is called a full solution anneal at 1950F in a vacuum furnace to relieve the various tensile and compressive stresses that have been imparted to it. Then the final light machining if needed and surface grinding as the last step. Some manufactures skip this operation because of cost and accept the dimensional changes that ensue.
Often I'll look at ss rotors on a new bike on the dealers floor. If the outer rim is slightly discolored to a tan color I know it has seen the anneal cycle during manufacture. Yes some have a ground OD for appearance so this eyeball test is sometimes not applicable.
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02 998 La Strega Bella
Last edited by Old Fart; 11-30-2009 at 03:29 AM.
Reason: can't fukkin spell
Crimson, i bought another set of stock pads from the dealer for my 2001 and they have same part #s as original, also GG designation same. The # on the copper collored backing plates is 07.6708.20, appear identical to originals including Toshiba and Brembo names. I see Yoyodyne offers 107 series pads, specifically what look like these that mention P4 2 pin and come in GG as well as HH. They also say sintered. I would have called them semi metallic.
Sir Old Fart, thanks for the input. I guess one could get a degree in steel metallurgy itself. I can't keep it all straight, martensitic, austenitic, cementite, ferrite, alpha/ gamma, eutectic points, etc. After letting my local machine shop guy look at the old discs he confirmed the ~.006 warp but also pointed to a few spots that he felt were thermal cracks beginning. Very small, I had not seen them. I had thought that now that they were warped that they were somewhat relieved and skinning em w a blanchard grinding would make em better than new. My only concern had been that they not end up much thinner than the carrier. After seeing the probable cracks I shelved the whole idea of servicing them. I set the stainless floaters aside. Was not convinced that those were much advantage other than allowing service. One thing I saw while researching brakes was a claim by, I believe Axis, that they cryogenically treated their iron rotors and that reduced warping tendency. Does that make sense to you?
I assume Brembo would do what they can to protest their reputation and would perform the 1950F full anneal, but the edges of these discs are painted on the edges so I would have to remove a bit to look for the coloration U mentioned. Would that coloration still be there after use?
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When smashing monuments, save the pedestals. They always come in handy. Stanislaw Lem
Cryo is also a decent approach to removing stresses. The metal is cooled to a very low temperature therefore it shrinks. As it warms up the stresses change and are somewhat relieved.
Yeah, all molecular constituents are initially confusing. Some are desirable and some are not. It all depends on the alloy. Once you spend some hours looking at them in a microscope looking at the solution of the material it'll all make sense. In the case of rotors it's all about the amount of nickel in the blend.
Brake pad choice, warpage
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