Non OEM brake discs cracking

[Gus 5]

anyone had a problem with this? swapped new rear brakes today and my rear disc was cracked in two places..not bad enough yet but

glad i changed it now. had a wobble when the handbrake was used since i had the car, so wasn't me doing it...what might have

caused it? handbrake up whilst the brakes were hot?

[hybrid 1039]

seen it happen after track racing leaving the hand brake on .. non bmw tho.

[Carl 3]

seen it happen after track racing leaving the hand brake on .. non bmw tho.

Yip, my OEM rear discs were cracked when I replaced them with some Brembos, I don't think they were meant to handle the heat that track braking generates. Got to learn to leave car in gear instead of using hand brake after tearing it up...is a common error for beginners (aye Udit) and I suspect that's what cracked mine - and they were severely cracked too!!!

[smokenbaby 0]

Yip, my OEM rear discs were cracked when I replaced them with some Brembos, I don't think they were meant to handle the heat that track braking generates. Got to learn to leave car in gear instead of using hand brake after tearing it up...is a common error for beginners (aye Udit) and I suspect that's what cracked mine - and they were severely cracked too!!!

If the rears are getting that hot I would be looking at a bias valve to try and taper some of the braking force away from the rear. You can also try running a cooling hose to the rear disk (be warned - it ultimately needs to cool both sides not just one or you will run the risk of warpage). It is never a good idea to put handbrake on once you get back to the pits, you will experience the problem above with rear brake sut up like on the E30 (subaru is the same). You will also boil your brake fluid inside the rear caliper if the hanbrake uses the rear caliper.

Many things we learnt with PRO7 in the early days.

[DCEIVN 0]

Yip, my OEM rear discs were cracked when I replaced them with some Brembos, I don't think they were meant to handle the heat that track braking generates. Got to learn to leave car in gear instead of using hand brake after tearing it up...is a common error for beginners (aye Udit) and I suspect that's what cracked mine - and they were severely cracked too!!!

Ahhh yes thanks for reminding me Carl.. though no damage was done - rear discs still in good condition. Anyhow, I think its because OEM discs heat up a lot more than aftermarket (good quality). Was it only one disc that was cracked because then you might need to start looking to see if there is a sticky piston or something. As the front brakes do most of the braking I would have though it was less necessary to divert air to the rears.