Brake discs for 370 mm “sub 8 package” on a Leon Cupra R 2018.

[TheSwede]

Hi all.

I experience pulsating during braking that increases with the temperature of the brakes. The pulsation has become worse since my last track day the other week.

I have the oem SHW 370 mm discs Item no 8J0615301K. They are rather expensive so I considered buying Zimmermann Item no 100.3367.70 instead since they are cheaper. Looks similar. I will order them from Germany, far better prices there compared to Sweden where I live!

Pads. Last time i bought Ferodo FDS1334 pads. They suit me well because I use the car mostly on ordinary roads but sometimes on track days.

My question - Are the Zimmerman discs a good alternative?

Btw, my SHW discs are since the car was new.

/Peter

A pic from a wheel rotation back to front today

 

[SuperV8]

Do you have a better/closer photo of each disc?
If you have a brake pulsation following a track day (high brake temps) I would suggest you have uneven friction material transfer.
When the pad friction is above it's 'happy' working temperture it can start to unevenly transfer onto the disc (causing a thick area) - especially if parked with brake on without any cooling laps?

Before spending money, I would try re-bedding in your brakes, 10 repeat snubs from about 60mph to 20mph (do not come to a stop whilst doing this) and fairly firm braking, around 50% of an ABS level stop. After you have done 10, drive normally to allow your brakes to cool, this can sometimes help remove thick uneven material transfered spots.

If you have a 25-50 micrometer (0.001mm) you can measure your disc thickness variation (DTV). Measure around the circumference of your discs, if you have one 'think' and/or one 'thin' spot it could be just DTV from normal use (more likley to happen from lots of motorway use), if you have more/random 'thick' spots you probabbly have uneven friction material transfer.

 

[TheSwede]

@SuperV8

Thanks for the answer.

I am familiar with “material transfer” during track use. Had it first on this car with the oem Pagid pads, then I changed to Brembo “vanilla” version same problem with material transfer. I have by hand (no machine) sanded the right disc with 240 grit after I detected blackish pads material. (Right - sitting in the car). Since the discs are identical R/L the right one seems to be hottest. The last 2 years I have used the Street/Track pads Ferodo 1334, much better. I haven’t detected any material from them on the discs, therefore I don’t think I have this problem for the moment.

I suspect if I had a Micrometer and measured the disc there would be differences in thickness as you describe. Perhaps the disc is floating uneven on the “pins” when it warms up?

I will use the car some time, without doing anything, and see if adjusts itself, wishful thinking ! If not better, perhaps the Zimmermann could be an alternative...if they are good enough.

PS I also use the RS3 Brake cooling ducts.

Se attached pics from today without flash and with flash .

 

[TheSwede]

I will also practise the 10 brake snubs as you recommend. I have done some heavy braking from fast to slow to see I it adjusts the problem, but not so many.

/Peter

 

[tracktoy]

Have you checked wheel barings