mikymu

If you look at the street 7.2 GT3 front rotors and compare with 2010 Cup they look almost identical except for more cross drilled holes on the Cup and some sort of powder coat on the dome of the hat on street rotor. The parts number are only off by the last digit as follow:

Street rotor: 99735140991
Cup rotor : 99735140992

The minimum thickness spec on both rotors are off by 2 mm. Street calls for 32 mm and Cup has 30 mm stamp on the hat. I would assume they are made the same way with same material and has different requirement for minimium thickness when it comes to street vs race use?

I walked around the paddock this pass weekend at Laguna Seca ALMS race and look at bunch of Cup car. Some 7.2 Cup are using rotors from 7.1 Cup and some 7.1 Cup are using rotors from 7.2 Cup. The 7.2 Cup still use street 997 TT rear rotors as shown below.

So, my question is will the street 7.2 GT3 front steel rotor fit on the 7.1 and 7.2 Cup?? My guess is yes. I have a set of street 7.2 GT3 front steel rotor coming and it will be interesting to see how it fits. Any one with first hand experience?

Street 7.2 GT3 front steel rotor



997 Cup front steel rotor



2010 Cup rear rotor is the same as street 997 TT rear rotor

911SLOW

I have some info for the street discs here:

https://rennlist.com/forums/8383634-post7.html


BTW the rear 2010 cup rotors
997.352.405.91 L
997.352.406.91 R
don't have the same part number as the TT ones.

Is there a big price difference ?

mikymu

Oh yeah! You can get a set of 997 TT rear rotors from suncoast for $333 vs $600 each from Porsche motorsport.

Do you happen to have the info on 2010 Cup front rotors as far as thickness etc.

911SLOW

Nice.. 5 years ago cup rotors were cheaper than street.

Will look for info for the cup discs.

Viperbob1

Have not tried to use a set of the 997TT rotors on a cup. Street rotor bolt holes for the lug bolts are usually 1mm smaller than the pins used for centerlocks on the Cups. Generally not just bolt-on. For this reason have never tried to put a street rotor on a Cup. You then have to worry about drilling out lug holes, etc. Pain.

mikymu

Not sure about 996 but 997 Cup can use street rotors ... direct fit

Viperbob1

Then bolt holes on the street rotors must be larger now. Still using the 964 part number drive pins. 996GT3 rotors would not fit.