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Age old question, I know, but I wanted a second opinion. Rotors are Stoptech 355x32. If I run my finger nail over them I can definitely catch some cracks. I bought them used with the cracking already started (used with Hawk blues and a skilled driver on slicks for a few days) and then I put two fall track days with XP8's and R888's on them and a few autocross events with AX6 pads. Heading to the tail of the Dragon in late april/early May and don't want to take any chances. There's plenty of thickness left but the cracks have me on the fence. Thoughts?
Last edited by Vettechris996; 03-24-2015 at 12:27 PM.
Yes - run them. Replace when a significant crack appears (can get fingernail into) or they clearly crack thru (very easy to spot or feel). If you want to be absolute certain on your trip to TOTD then go ahead and replace but personally I'd have no problem running those.
Yes - run them. Replace when a significant crack appears (can get fingernail into) or they clearly crack thru (very easy to spot or feel). If you want to be absolute certain on your trip to TOTD then go ahead and replace but personally I'd have no problem running those.
They probably have at least one or two track days left on them so street/highway driving and the Tail of the Dragon will be no issue at all. You really can't safely go as fast on the Tail of the Dragon as people think. Track events where speeds are far higher with subsequent much higher braking forces put much more stress on rotors and brake fluid than it will do. The difference is coming into a corner at 120 to 150 and slowing to 60 or 70 Vs coming into the corner at 80 or less and slowing to 30 or 45.
Given the history you provided it's foolish to continue to use these rotors without knowing how deep the cracks are. A crack that extends all the way through the base metal on a rotor is a recipe for disaster; surface cracks, not so much. You indicated that the rotor rings have plenty of wear surface left; if possible you should have the rotors resurfaced. If the cracks disappear, the rotors are still serviceable, if not replace the rings.
Anyone who tracks a car regularly can tell you that a cracked rotor is no big deal. The rotor splits, you feel it in the pedal and sometimes in high g turns, and you pull in and change it. I've cracked dozens on track, it doesn't crack all the way to the back side and fail, it just splits, 99% on the outside face. If you resurface them, they absolutely will crack the next time you put them on track. A trick to extend life is to swap them right to left as one side usually takes more abuse, most likely the left. Ignore the vane direction at this point, rotor failure is imminent anyway, and it might get you one more day.
Originally Posted by ipuig
Given the history you provided it's foolish to continue to use these rotors without knowing how deep the cracks are. A crack that extends all the way through the base metal on a rotor is a recipe for disaster; surface cracks, not so much. You indicated that the rotor rings have plenty of wear surface left; if possible you should have the rotors resurfaced. If the cracks disappear, the rotors are still serviceable, if not replace the rings.
03-24-2015, 12:22 PM
Should I run these rotors?
They probably have at least one or two track days left on them so street/highway driving and the Tail of the Dragon will be no issue at all. You really can't safely go as fast on the Tail of the Dragon as people think. Track events where speeds are far higher with subsequent much higher braking forces put much more stress on rotors and brake fluid than it will do. The difference is coming into a corner at 120 to 150 and slowing to 60 or 70 Vs coming into the corner at 80 or less and slowing to 30 or 45.
