brake pads for track use

[ADracing]

Sounds like you forgot to bed the pads in so got uneven material transfer.

What's the procedure with these? I did very little street driving before taking them to track.

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[Rocksandblues]

My experience so far.

I did a cool track day on stock pads/fluid when I first got the car. Was a bit kinder to it than my next experience, and I used up a lot of the stock pads, but other than that had no major issues.

For the second track day I put CSG C21 front /C11 rear pads and bled with RBF 660. Much hotter day.

Bed in procedure was driving 2 minutes to my hotel with only a few lights (braking normal pressure). Then driving another 5-10 minutes to the track (some hard stops along the way). Then I immediately went on track with hard braking moments. By the end of the 3rd lap I was having some shaking when braking, but by end of the first session the car was shaking pretty violently (only when braking).

We tried bleeding brakes a ton of times because originally felt like abs kicking on so thought there may be air bubbles. But even after bleeding many times I'm getting it by end of lap 1 or lap 2 as speeds and temps come up.

So basically, we assumed the rotors became warped almost immediately from these pads. To be fair it was a hot day and I wasn't being kind to them on track, but I thought the stock rotors could handle these pads?

For street driving they are okay, but as temps start coming up on track it gets progressively worse.

• Has anyone else experienced this warping so quickly?
• Do I go with the FCP Euro replacements or will I be in the same situation?
• Was my bed-in procedure the issue?
• Did I bleed incorrectly?
• They aren't visibly warped when I spin the wheel and look with the wheel off/car in the air, do I see if somebody can machine the stock rotors first and see if that helps before proceeding?

Thanks in advance

That’s not rotors. You didn’t bed in even remotely close

 

[razorlab]

Actual warped rotors are an old wives tale. 100% pad deposits from not bedding them in correctly.

https://centricparts.com/getmedia/b..._Whitepaper_B1-Warped-Brake-Disc-8-2018_1.pdf


Here is how I bed in my pads. Have worked well for me over the last 20 years....

60mph to 10mph 4-5x. Threshold braking the whole time
80mph to 20mph 3-5x. Threshold braking the whole time

You should be good after that.

 

[ADracing]

That’s not rotors. You didn’t bed in even remotely close

Okay, so any suggestions?

 

[razorlab]

Okay, so any suggestions?

See my post above.

 

[ADracing]

Actual warped rotors are an old wives tale. 100% pad deposits from not bedding them in correctly.

https://centricparts.com/getmedia/b..._Whitepaper_B1-Warped-Brake-Disc-8-2018_1.pdf


Here is how I bed in my pads. Have worked well for me over the last 20 years....

60mph to 10mph 4-5x. Threshold braking the whole time
80mph to 20mph 3-5x. Threshold braking the whole time

You should be good after that.

I will try this. Thanks. I'm assuming no waiting time between these steps? And I'm assuming it possible to bring the pad/rotor surfaces back to life even after an improper bed in procedure?

 

[razorlab]

I will try this. Thanks. I'm assuming no waiting time between these steps? And I'm assuming it possible to bring the pad/rotor surfaces back to life even after an improper bed in procedure?

Great question, I left out an important step. You do all of what I mentioned back to back, then make sure you either park the car and let the rotors cool or drive without using the brakes (like on the hwy). whichever is easier for you.

Yes, this will properly bed in pads even after you have judders. What you want is an even pad material deposit. The judder you feel is uneven pad deposit.

The key is really lean into the brakes and threshold brake. If you do it right, you will smell the brakes a lot.

 

[kaj]

I will try this. Thanks. I'm assuming no waiting time between these steps? And I'm assuming it possible to bring the pad/rotor surfaces back to life even after an improper bed in procedure?

You want them really hot. Each manufacturer usually has their own procedure. Check their website.
Try the bedding them in and see if it helps.
I've had to sand the old material off before starting over, once (too much street driving after bed in/track day) but hopefully you won't need to worry about that.
P.S. threshold braking= very important. You do NOT want ABS kicking in.

 

[ADracing]

Great question, I left out an important step. You do all of what I mentioned back to back, then make sure you either park the car and let the rotors cool or drive without using the brakes (like on the hwy). whichever is easier for you.

Yes, this will properly bed in pads even after you have judders. What you want is an even pad material deposit. The judder you feel is uneven pad deposit.

The key is really lean into the brakes and threshold brake. If you do it right, you will smell the brakes a lot.

You want them really hot. Each manufacturer usually has their own procedure. Check their website.
Try the bedding them in and see if it helps.
I've had to sand the old material off before starting over, once (too much street driving after bed in/track day) but hopefully you won't need to worry about that.
P.S. threshold braking= very important. You do NOT want ABS kicking in.

Thanks guys. I will give it a go when it's not raining here. I'll be happily surprised if this works. I certainly wasn't easy on them on track, and it seemed like the hotter I got them the worse the shaking became. Either way I'll push through the shaking if it occurs while this is happening. I'll probably grab some FCP Euro Rotors either way. Looks like they are on labor weekend special.

 

[kaj]

Good luck, dude! You'll have it fixed in no time.

 

[ADracing]

OEM rotors
Front Left: 34116860911
Front Right: 34116860912
Rear: 34216860925

Brembo
Front Left: 09D09413
Front Right: 09D09513

Also, can somebody clarify these sku's?

Both have the same model number but they are priced quite differently and have different sku's. Both left sided. One came up when searching z4 m40i and the other was linked in this thread.

option 1

option 2

Sorry guys one last thing. Do you know the difference between these two? Same model numbers but different sku's and prices. Have the cheaper ones in my cart.

 

[Rocksandblues]

Okay, so any suggestions?

bed them in properly. Ask for trackhelp
In your area. Can not be done on regular roads

it is violent

you can re cut them in

 

[razorlab]

Sorry guys one last thing. Do you know the difference between these two? Same model numbers but different sku's and prices. Have the cheaper ones in my cart.

I don't unfortunately. OEM has aluminum hats pressed into iron rotors.

 

[FLtrackdays]

I've used a low grit sandpaper when keeping my old rotors if the pads didn't properly mate to the old rotors. When using new pads and rotors, the bed in is extremely easy. Rotors were cheap in my previous track cars and didn't require as hard of a bed in, with new rotors & pads every time. So... if using the old rotors, you definitely have to bed them in longer & harder to get a good transfer film. Hence why @razorlab and @Rocksandblues are describing the best way to really heat up those old rotors to mate to a new set of pads. Hope that helps...

 

[ADracing]

I don't unfortunately. OEM has aluminum hats pressed into iron rotors.

Looks like the difference between the 2 is those hats. One is probably full iron and other is iron with aluminum hats.

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