[quote=" Dori Dori 1. Laser cut rotor hats aren't drilled.[/quote]Ah, fine, I'll give ya that one. But they might as well be drilled -- laser cutting produces a heat-affected-zone around the hole that weakens the surrounding metal -- just as bad, if not worse, than the stresses created by drilling a hole!
And the comment in your other message about stress risers still applies to aluminum hats that are drilled.
Quote »2. Do a search on the internet for cast-in-place holes. You'll find plenty of information and debates on them.[/quote]I'm talking about lug holes in brake rotor hats, not cast-in holes like Porsches use on their "cross-drilled' (cross-cast??) rotors. A quick google search revealed nothing of the former -- which, if you remember, is what this discussion is all about. If you have any links handy, please provide them so that we may all learn.
Quote »3. How much heat is needed to make a wheel bearing fail? You don't even know.[/quote]You're right, I don't know how much heat is needed. But I can tell you with 100% certainty that it's less than what's required to make the material in the hat of the brake rotor fail. Why? Physics -- and common sense.
Quote »5. Wow. One car uses them (the redrilled rotors). [/quote]You asked for examples, I gave you one that I thought of off the top of my head. You still haven't gotten back to me with your assignment.
My car has redrilled rotors too, but I've only taken them to the track twice. And no, they didn't fail. But I'm hardly a serious racer.
Quote » Auto-x no less. [/quote]I suggest you look up the difference between SCCA Solo-I and SCCA Solo-II. I'll even give you a link to help you out:
http://www.scca.org .
Quote »6. THere are racers that use steel hats.[/quote]
Yes, I realize this -- is there anyone that uses steel hats if the series rules allow aluminum? I doubt it.
Quote » Also titanium hats.[/quote]Sweet. Titanium is cool. But it's not relevant to this discussion.
Quote »but if the bearing can reach those temps, and knowing the way heat conducts through the rotor, the rotor hat can surely see temps close to 1000degF.[/quote]I'm not so sure...1000 deg. F seems a little high to me. Granted, this is just me talking out of my *** in this instance. But remember, iron is a pretty poor thermal conductor -- and it gets worse at elevated temperatures.
Quote »With those temps, and the possible stress spot, cracking and warping are more likely to occur.[/quote]Sure, they're more likely. But if cracks in this region don't occur with non-redrilled 1-piece rotors, what makes you think that they would suddenly start happening in a rotor with only 3 extra holes on top of the original 5?
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