A friend was told by two giants in the MINI world that they've heard reports that R56 rotors are warping and that JCW drilled/slotted rotors are a must for Autocross and Track, or better yet full brake upgrade. Track I could buy, though I'd venture to guess only a VERY small handful of folks have tracked their R56's significantly yet.

I've never heard of anyone outdriving their brakes (to the point of damaging them) on ANY car on a parking lot autocross (as opposed to SOLO 1 track competition). There is just way too little braking in a 60 second run to harm anything.

They even went so far as to describe the R56 standard rotors as "Ol Lady Rotors". One was a vendor and one had nothing to sell. Did my friend misunderstand these folks, or did I discover a rift in the fabric of the universe?

My own understanding of crossdrilled/slotted rotors is that they help keep the rotor cooler under track competition, but otherwise they're a poor option for a daily driver as they can be noisier, can't be resurfaced (though neither can any BMW/MINI rotor as they're cast in minimum spec, no?), are more expensive, the cross drilled cast iron can result in a higher failure rate than unmollested ventillated rotors, and they have less surface area for the pads to adhere to, so in theory, all other brake factors being equal, they'd be an inferior stopper.

We all know brakes will cook on a race course with relentless use, but aside from that extreme, which I'd be surprised to find out has been documented on an R56 with more than say a car or two in the Challenge series(??), why would folks tell my friend that it's a well known problem on the R56??

 

I call BS... I've heard of no issues. I've seen plenty of R56's on the track and at the autocrosses, all running stock rotors with NO issues.

You don't want to sit on the brakes in the pits or grid after coming in from a session - that will do bad things to ANY rotor.

 

One of the things that folks forget to do when picking up a new car is to properly bed the pads. It's understandable since you just got a new car and all. Really all you want to do is drive it; not worry about things such as break-in or bedding pads. This may very well explain the cause of "warped" rotors on a new car.

As for cross drilling - repeat after me - cross drilled rotors are evil. EVIL. EEEEEEEEEVVVVVVVVIIIIIIIIIIIIILLLLLLLLLLLLLLLLLLLL LLLL!!!!!

 

IMHO, drilled are ok for the track if always checked for cracks. Slotted are almost as good as drilled for heat and water dissipation without the risk of cracking. Slotted are my personal choice for track duty. Neither are really needed for the street.

 

Frequenting a few of the big MINI enthusiast sites... I've heard of exactly 0 issues with R56 rotors. I personally think the stock R56 brakes could use some better pads, but that's about it.

Thak being said, I will be getting drilled and slotted rotor all around. In all honesty, it's for the Bling... but I do think they work better in really wet conditions (read Washington State) as they give a place for water to escape under wet braking.

 

Cross drilled/Slotted rotors DECREASE rotor surface area, causing the brakes to run hotter. The ONLY benefit lies in their ability to allow the pads to "Outgas" when they get heated over temp. Crossdrilled/Slotted rotors cover up for crappy pad selection. With a good set of pads/fluid there shouldn't be any reason to upgrade to larger/modified rotors unless you're going to be going CRAZY at the track and you're looking for that last 5%. As far as i've seen a good set of pads and fluid with SS lines can work in 95%+ of all track scenerio's. The only reason to go with a BBK is for the bling, or if you're truely maxing out the stock components on the track. With a full blown racing compound pad I can't imagine you're going to get fade, even with the stock rotors.

That being said, as far as I know the R56 runs the JCW brake's on the R53 as standard, I can't see how they could be any worse than the R53 brakes, which are phenominal from the factory IMO.

 

Nick, Thanks for the better description. I believe that the heat generated is the same unless you're braking more. Yep, slightly less surface, but added cooling and aggressive pads last better on my racecar. The outgassing does make a huge diff in racing conditions, probably not so much just for track days. You might want to pay attn to the ATE fluid. I've had friends with some leaking issues. Couldn't tell you why. It's been on full blown racers.

msh, I'm a seattle guy also. If you're tracking your car, pay attn to spider cracks. Never seen a rotor explode, but hoping to never see one. That's why I stay with slots.

Mark