Ajjra

Track rats please advise on condition of these rotors. Can I still do DE events on these or are they done?

Thanks

mdrums

Change them

Ajjra

I already have. They're off the car I'm just wondering if I took them off too early or if I can use them as spares...

TRAKCAR

That is what my spares look like.
You can finish a weekend on them, maybe more.

Keep in mind they crack all the way through only when parked cooling down, the more time you give them cooling down while driving the longer they last.

You usually notice it when you are about to go out again, you can hear and feel it in the pedal.

Ajjra

Great! Thanks Peter.

GT3DE

look for cracks at outside edge, when that happens they are trash, otherwise still good.

dantzig

Porsche spec is 7mm crack length. Those look like a lot more than that. I wouldn't use them.

In my experience, slotted rotors last a lot longer.

Izzone

Three hole connecting or outside crack

Besides that still good

Most cracking is heat check, not all the way thru cracks

tcsracing1

they are offically street only rotors.

Steve Weiner-Rennsport Systems

Everyone has their own guidelines to be certain, however aside from wear, I only replace them when two holes connect or when cracks extend to the outer edge.

There are more durable rotors than OEM, however they aren't as inexpensive,. .

ir_fuel

Inexpensive?
Wouldn't call an OEM front rotor of a 997.2 GT3 'inexpensive'

ir_fuel

Isn't that more for street-oriented usage?

I always heard that as long as the cracks do not connect 2 holes or extend to the edge it is still ok.

I must say there is one very long crack on that picture. I would replace em too if the rest of the disc is in the same shape.

dantzig

It only takes one to cause a failure. Fatigue crack growth rate in metals is typically proportional to crack length raised to the 3/2 to 5/2 power. So big cracks grow much faster than smaller ones.

Risk to reward ratio doesn't seem very favorable to me. YMMV...

Jon

Steve Weiner-Rennsport Systems

Compared to the AP racing rotor replacements we use, they sure are,..

Still,...the payoff is in extended longevity and thats less $$$ the long run.

ir_fuel

That is a different story of course


If you see the price delta between OEM mk1 350mm rotor and mk2 380mm rotor, they became a lot more expensive.

I switched to PFC for the fronts.