Rotor issues

[lautray]

This is aimed more at Matt or Neil or other brake guru: I have the PBR PK1 kit on my vx ss, with DBA 4048sl/sr & 4049sl/sr & TS2000 Ferodo's front/rear. After doing circuit days, I have cracked two left rear rotors in the same basic spot on two separate occasions:

http://www.trackchat.com.au/media/data/500/medium/DSC01105.JPG

http://www.trackchat.com.au/media/data/500/medium/DSC01107.JPG

Also, have warped the fronts, but after a machining, they came good.

Getting sick of throwing good money after bad, is there an "easy" out here? I was thinking of buying a pair of rear 4049 (not sl/sr i.e. without the slots) as it seems this is their weakest point, especially since the rotor thickness is much thinner (315x18mm rear, versus 330x32mm for the fronts). Would spec'ing up to a DS2500 help as they are rated at a higher temperature? Is there another option for rotors i.e. brand? Would a set of DBA 5000's work better?

Eventually, would be looking at a set of 4 piston AP's front & rear. Probably keep with 330mm front & 315mm rear. What is the next rotor up from 330 & 315? And, more importantly, will they fit in a 17" rim?

[dattoman]

Erik
Your car seems to be the only car I know of that has done this ............ twice !!

DBA don't make a 5000 series rear to replace it I'm afraid

I have some theories but without more info and some tests I'll keep them to myself

I'd be trying some discs either without slots or with more conventional slots that don't go right to the edge of the disc

I'm sure Matt will have something suitable to replace them

[PSI38L]

Erik,

try get a set without the wiper slots, or get a plain set and get some one to groove them for you.

the trouble by going to DS2500 is you will have more friction, so you will create more temp.

there are some kits out there but the nest one of know of is 362/332 but you will need 18"

[RBS MATT]

Have you sent the rotors to DBA for checking ? if not do so or send to me.
Have you checked the temp paint to see if it changed colour ?
How long had the rotors been on the car before doing track days?
Do you run ducting to the brakes and if so is it to the centre of the rotor hub or the rotor face?

As with Dattoman there are theories and to have two crack on the same side is suss.The fronts to warp can sometimes be caused by suspension problems and worn bushes especially under heavy braking.
Do the brakes lock up on the rear just before they crack( if it is noticeable)
Are the rotors torqued up with the right configuration ?
There can be so many questions and apart from RDA there is not much although i can get another brand but would have to get them slotted and maybe at a good price to try them out.

If you can answer some of these questions i will try and follow it up for you .