Hello.

I have been poking around looking at new rotors on all 4 corners. I am hoping to go 2 piece at least up front. I managed to generate cracking in my DBA 4000XS (hate the cross drilling but free form previous owner) rotors. I was planning on getting either some DBA or Girodisc fronts. I currently compete in track, hillclimb and autox, the car is probably 70+% track at this point. My current set up is DBA4000s with ST43 compound brakes. Car weighs approximately 3400lbs with me in it.

Now, in looking at the two options I was reading GD are directional vane vs the DBA kangaroo paw, I have heard differing information which is better. I noticed it seems that there is a slight weight difference in the rotors (GD being lighter) and wanted to see if there was a distinct thermal mass difference there, or if the vane design compensates somehow. And then the final part, will either of these be more resistant to cracking? I was hoping to find people who might have some real world experience with both to weigh in.

Thank you.

 

i've used both, you won't feel a difference between either. can't comment on weight or heat evap but i developed cracks in both. you will just get those when you're on the track .

 

From my customer reports - 2-piece floating discs give a much more consistent pedal feel when everything is hot.
Girodisc is curved vane like you said - which actually helps cool the disc. Kangaroo paw is just marketing, does nothing.

 

Same here - did not see or feel a major difference between DBA and G. However the PFs tended to last a lot longer.

 

I've used the dba two piece and got cracks doing track days, now I've got 4000s which haven't cracked but will when I start doing track days. Just try and warm them up slowly for a good lap, that's what I was told keeps the cracking less, but they'll still crack anyway.