I just had to say something Shimmy your discs are bad........
Reading the thread your are all talking about pad and disc wear. I think the cracks are caused by overheating the components and is not good err very dangerous can cause exploding disc with obvious consequences....

I google searched this artical about overheating discs:

"Cracked Discs

Braking surface cracks are seen as radial cracks appearing in the braking surface and rounding the edge of the disc at the inside or outside diameter of the braking surface.
These cracks are always caused by excessive heat which is usually caused by torque imbalance which shifts a greater share of the braking function to only a few of the vehicle brakes. The brakes which are providing a greater share of the braking action, will always be the ones to show the greater disc wear and will sometimes crack.
Cracked discs must always be replaced. If the disc is not replaced the cracks will gradually get worse and can eventually progress into the barrel section. After the discs are replaced the braking system should be checked for proper balance."

Interesting reading...someone has already mentioned inbalance from front to rear so not entirley overlooked.

By the way wheels are great eventually fitted new Kumhos, the ride is not to bad just have to drive round those pot holes.:supz:

AP discs usually crack - just hairline fractures at first which get worse over time/usage. Quite normal - to a degree...

will check for imbalance but i think they are fine

just been overused on track and very hard worked,

so far a front set lasts me a year and i wouldnt mind betting everytime they have been under minimum thickness

all in all each set does about 2100 track miles plus a load or road miles i between

I tend to swap them out as soon as i notice any cracks that go to the outer edge of the disc - seems to work so far

I thank you ! :hahaha:


Shim , try sitting further back mate, would really help with the ..uh ..weight distribution !!

I collected my car from Simpson's today having had discs/pads changed all round. I elected to stay with AP disc/Pagid RS29 pad combo as they have served me well so far. :thumbs:

Inspecting my old AP front discs revealed that i had lots of the small (normal) heat cracks and just one of those cracks had radiated to the disc edge. So not too bad really.

Top marks to Ant & Julian as always and the car is spot on, i just need to recover after the dent to my bank balance...! :bigcry:

So what rear discs do you use????? Standard OEM or something else.


I tried the PF front discs this time around and so far so good :thumbs: I agree with pintpot regarding the RS29's top pads and mine rarely squeak on the road.

I did stick with standard originally but have now moved to rear AP also.

My rears are nearly FUBAR'd so might give the AP's a shot.

They def look better ;)

The thing is that the OEM ones have aluminium center hub, while the APs are all metal.
I bet the APs are heavier ;)

Did anyone measure the weight of the rear APs ?
The OEM ones are 6.5kg