Gretch

In follow up to the following:

"Gretch:
I would like nothing better than to be proven wrong. That's why I hope for your sake your rotors don't suffer the cracks I've seen on others.

Let us all know in a few years how they're holding up. BTW, there is a way to keep them from cracking - don't apply the brakes. :^(
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So the answer is that I have now reached 65,000 miles on my C4 rotors and they are fine....at least the holes are......the next time I do a brake job I will replace the rotors. However, since the original brake pads lasted 5 years and 65,000 miles it will be a while till I can report back. The rotors are still in spec.

On the 928.....I only put 5,000 or so miles on the car since I did the brakes 3 years ago.......those holes are doing just fine too.

No cracks anywhere in any of a total of 8 rotors.

Predictions to the contrary, the sky did not fall.......

Mark

my cross-drilled rotors have been GREATLY abused via many a DE and AX...NO PROBLEMS!

Gretch

No surprise, although maybe I should be, as ed said the holes were ok for track use, but for street use I was risking getting cancer.......of the holes.....

Maybe yours held up because they were driled as opposed to cast......WAIT.....that is the reason they cast the holes...so there would be less pre-stress on them thar holes...........

You gotta admit, the marketing brilliance of these Zimmerman guys.....selling me rotors that look like swiss cheese.......


BTW, solid rotors on the a6 bi-turbo quattro. the car has about 60k miles on it and is on its 3rd set of (warranty covered) rotors........go figure?????

Garth S

A wholly credible report ...

Gretch

Holey Rotors, Batman!!!!!

Actually I think Zimmerman figured out how to save on cast iron cost by drilling out some material and reusing it in the manufacture of more rotors, then when they figured out they could avod the labor cost by CASTING the holes in the rotors.....URIKKA!!!!!!!

Vee vill turn iron filings into gold!!!!!

Anyway.......nothing to see here folks, keeeeeeep moving....the holes are gonna be just fine......

heinrich

Gretch you have just disproven what I thought on the subject. I looked at Don Hanson's a few years back and he said he consumed them like swiss cheese at a cheese and wine gala event. The holes were cracked almost to the edges. I think the difference is:

Lighter use. I like the look. Based on your report I can now happily but drilled rotors, thanks ... I have always liked the look.

Chris Lockhart

I've had the same results as Gretch. I've been running the Zimmerman cast hole rotors all the way around on my GT, for about 3 years. Approximately 35K miles of heavy street use, a few Auto X's, and those occasional 150+ mph runs near my home, (where you really need some good binders) and nary a crack has appeared.

I can see where that would be an issue for a heavily modified track car like Don's, but not on the everyday street 928. Just my 2 cents, based on a few miles with them.

heinrich

Thanks Chris, these are the first real-world results I find useful as I am a street guy.

sweanders

I am using the same rotors on the Cup car and cracks are a plenty. I have been recommended to drive on teh rotors until two holes are connected, a crack reaches the edge of the rotor or until it is too thin. Mostly track use for my car.

shaaark89

i have the same experience as anders. replace them yearly on the track car or if the cracks connect two holes or reach the edge. last new set lasted one session before the cracks appeared, but so what? haven't had any connect or reach the edge. even if the rotor fails (which i've seen on the track,) it's typically not a disaster.
street car has no cracks whatsoever after 3 years.

Thaddeus

What is the benefit of drilled rotors? Saved weight? Improved cooling?

shaaark89

cooling mostly. typically not necessary on a street car but it looks cool.

Gretch

Yep, for street use, "improved cool factor" that is why I did it, and I got what I wanted....

FlyingDog

Wilwood's site says that drilled rotors don't cool any better and may actually be worse for heat. They claim the benefit is reduced rotating mass (and of cool factor on the street).

Randy V

Just another Ruiz edict proven to be false...