alex_00s

iTrader: (18)

My car: version 6 STi with 18" Rotas
My brakes: Ksport 8 pots ft, 6 pots rr with 356mm grooved discs all round and DS2500 pads all round. Braided lines and Dot 5 fluid.

I fitted these new and have only done a few thousand miles with them, but right from day 1 I've had a bit of an issue with them.

They stop really well dont get me wrong, very happy about that, but after aggressive braking they start to judder... and not only when actually braking, when just driving the wheels judder.

Its like all the balancing weights have fallen off and the steering wheel is shaking the life out of my hands.

After gentle driving for a few miles it diserpates and goes away completely.

I cant figure out whats happening?

I fitted the discs the with correct orientation, but was told to reverse them so the grooves face the other way and this would cure the problem? Something about them cutting into the pad and residue building up causing the judder??

Any advice before I give that a go?

Thanks
Alex


Disc orientation with grooves facing forwards (cutting into the pad).

stockcar

more important than the groove orientation is the internal vane structure, do they have curved or straight coolinbg vanes??

alyn

alex_00s

iTrader: (18)

I'll check and get back to you...

So regardless of the grooves, the important thing is to get the cooling vanes the right way round. I think they're curved... if they are then the curves should be pointing 4wards to trap air in, or backwards to let the heat out?

Henrik

iTrader: (5)

Same as mine... I've just sent my discs off to ian at godspeed to get them skimmed.

In my case, the problem seems to be a rust spot on the inside of the passenger side disc.

I unfortunately didnt drive the car much over winter, and where the pad sat against the disc it rusted quite badly (even a track day didnt take the rust of in that spot).

I'm hoping a skim will sort it, otherwise it's new disc time...

Henrik

iTrader: (5)

Oh, my problem only occurs on hot brakes whilst braking.

every1sgottablue1

The grooves are going the same way as mine Alex

-shane-

iTrader: (40)

I also get this vibration on my 8 pot k sports, I'm going to change the pads soon see If that helps, it only happens from high speed and not all the time, sometimes I get a loud drown (been told that's normal due to the groves) I'm also replacing all 4 tyres so will make sure all the tyres are balanced correctly

alex_00s

iTrader: (18)

Yeah its when they are hott as per aggressive braking and only noticable when driving on A or M roads at speed (over 70mph approx).

I have a set of the std kspot pads at home, could try those...

Lee - do your grooves go the same way as mine?

-shane-

iTrader: (40)

I'm currently using the standard k sport pads so hoping changing might help

alex_00s

iTrader: (18)

Do you not experience the judder on heavy (constant - aggressive) braking?

I wonder if it is just the pads... I thought DS2500 were the best, but then again probably are for track use and you wouldnt experience the judder so much with a track car... hmm...

every1sgottablue1

Same way mate do a google search for grooved discs, looks like they all do mate!

-shane-

iTrader: (40)

Yes mate, Im going to try the ebc bluestuff pads in a couple of weeks

alex_00s

iTrader: (18)

I'd like to hear from any professional/experts in the braking field to what the cause and effect is of the judder?

They must dip in and out of this section now and then?

alex_00s

iTrader: (18)

I will be seeing my car 2moro, its been off the road a few weeks with a seized box.

I'll check the vents inside the discs. And if I cant change them round I might stick the Ksport pads on and give them a go

greg320

iTrader: (15)

the grooves on my disks face the other way, they were fitted by AP racing

alex_00s

iTrader: (18)

The grooves face 4wards and the internal vents face backwards...

So if I swap them round the grooves will face backwards and vents 4wards...

What are the vents for? Cooling I know, but how are they sposed to cool? By expelling heat or drawing cool air in??

stockcar

if you imagine looking at the top half of the disc the curved internal cooling vanes should curl towards the back of the car.........

hope that explains things, alyn

alex_00s

iTrader: (18)

Yeah they do and I checked my mates M3 and they also curl 2ward the back... ok so must be sumin else then... hmm...