True. And, they could both be destroyed very easily with a bomb; therefore they are indeed subject to failure caused by a common element. If rotors are made with common materials and manufacturing processes, and exposed to similar heat and stress they could fail, regardless of what vehicle they are on. To think the stresses put onto rotors are totally unique as long as they are on an S2000 is a rather bizzare theory.

 

Exactly...

And-
because someone didn't replace a $40 rotor because they were trying to get their last foolish nickel's worth out of it.

 

Look guys, change 'em whenerver you want. Just don't assume, without evidence, that your assessment of the risk is necessarily the correct assessment of the risk.

If you have evidence, please bring it forward. It would be of use to us all.

In the mean time, I will continue to rely on my own assessment of the risk.

But as I said before, the point here is that the failure mode is cracking. Either small cracks ("heat checking") that eventually make the rotor too rough to use, or those same small cracks that propagate into a large crack all the way through one face of the rotor. It is not generally necessary to worry about measuring the rotor thickness, because one or the other of the crack failures will occur before the rotor gets to minimum thickness.

That's not the case, necessarily, on an untracked car.

 

I've had my rotor crack and separate completely from the hat. So the caliper was holding the disc that was attached to nothing.

Bitterman was driving my car when the failure happened (figures )

Wasn't that catastrophic because it happened in a corner w/ lots of run off. T11 at sears, would suck a lot more.

I run my rotors till the point 1" or greater checks/cracks are visible. You usually can feel them in the pedal. Most of you replace them MUCH earlier than me.

-Ry

 

Yow. OK, that's a datapoint. However, that's an entirely different cracking mode. Or did the crack start radially, like normal, but propagate into the hat area?

 

yes exactly cracked radially that once it opened enuf seperated from the hat.

 

Mmmm. OK. There's one.

Was this an OEM rotor, or a knockoff design? I'm sure it could happen either way, but I'm curious. The details of the casting where the hat attaches to the swept part of the rotor could be significant.

Anyway, nobody (including me) is arguing that you want to have a full crack in the rotor before you take them off. I've retired a lot more rotors before the cracks propagated all the way through than I have after they did. But also nobody (I think) is arguing that you should panic the first time you see small cracks (aka "heat checking") forming on the swept surfaces.

In the end, it becomes a question of using your own judgment about how much heat checking is too much to go out on again.

 

2003 so I was still running oem rotors.

 

Yes. As you know, I don't track my S2000 any more, but I put between 30 and 40 track days on it. I did change the rear rotors once for being too thin, when the heat cracking wasn't yet a concern.

 

OK, another data point. Wow, Mark, you must have been WAY under the operating temp on those pads.