SteveA

iTrader: (1)

The pictures below show pad material transfer on brand new stoptech front rotors and previously clean OEM Brembo rear rotors after 3x20 minute track sessions with new CCX pads. The CCX pads were recommended as being a suitable dual purpose pad as I have always used seperate track/road pads and was getting tired of changing them.

Prior to install the Stoptech rotors were thoroughly washed with soap and water to get rid of the anti-rust compound. The pads were installed and the recommended bed in procedure was followed, i.e. 10x60-5mph hard stops followed by 5x80mph stops followed by 20 minutes of cool down driving with no brake use. The brakes were then left to cool to ambient and the bed in cycle was repeated with a couple of 100mph stops added for good measure. At that point the rotors had a textbook blue haze with the start of an even grey tinge from pad material and felt great.

The track run was the first test for the Stoptechs and pad combo. everything felt good during the runs. The brakes were used hard but cool down laps were used for each session with no braking. All seemed fine.

However, on the way home from the track I noticed a moderate vibration under normal braking pressure and inspection subsequently showed uneven deposits of pad material as per the pictures.

My questions are as follows:


1. Am I right in thinking this indicates that the CCX pads do not have enough heat range for the level of track sessions they experienced? In which case I am back to needing a higher heat range track pad and living with swapping road/track pads.

2. Has anyone else had similar issues with CCX pads in track applications?

3. What's the best way to clean up these rotors and get rid of the vibration without doing any damage? I was thinking I probably need a harder race pad run cold to clean them up, but don't have any for the fronts and only some old PFC97s for the rear.

Billhyco

iTrader: (14)

1. I live with swapping them at the track
2. never used these pads
3. brake lathe

SteveA

iTrader: (1)

I can live with swapping pads too, but the whole point of CC-X pads was that they are supposed to be able to cope with both road and circuit racing. That's why I am questioning my interpretation of uneven pad depositing. Normally that means they overheated, but I am surprised to get this result this easily with the Stoptech's and am wondering if I did something wrong not bedding them in properly?

Machining the rotors might be a solution, but the front rotors have less than two hours driving on them so a lathe seems a bit extreme! Stoptech suggest using Garnet paper for mild deposits or a decent semi metallic pad. I haven't had this problem before despite a lot of tracking but I never used CC-X pads before either. I am interested if others have used those or other processes to successfully remove uneven pad deposits and brake vibrations without resorting to machining.


Maybe just driving around at normal road temps for a few days they will clean themselves up, but I don't want to make things worse so I am asking for informed opinions?

Dave 90TT

iTrader: (4)

Here's the thing: anything that is dual purpose is not going to do either one of those things very well. This applies to brake pads, just like anything else. I recommend getting a good set of race pads for use, and a good set of daily driver/street pads as well. I understand it is a PITA, but it is worth it, as well, as you have found.

For cleaning up the rotors, a good set of race pads will do so; regular daily driving might work, but it might not.

GaryM05

I used to get that with the Carbotech pads that I started with in the Stoptechs. A day or two of driving those on the street after an event would clean the deposits off of the rotors, and then I would switch back to street pads until the next event.

However, the fact that your CCX pads were designed as a dual-purpose pad might mean that they won't be quite abrasive enough at low temps to remove the deposits during normal street driving, but it's worth a shot.

I would second Dave's advice to get dedicated pads for each environment. It will make your brakes perform much better, all the time, with no trade-offs (other than making the time to swap pads before and after the event).

SteveA

iTrader: (1)

Thanks for the comments.

I have done a bit more research and can't find any information to indicate I bedded them in wrong. It seems they just got too hot for the compound. I guess the evidence speaks for itself, they aren't really suitable for my type of track application.

Pity I bought three sets of them, but I guess I won't have to buy road pads for a while!

daytona350z

iTrader: (19)

were you on r-comps or just street tires?

SteveA

iTrader: (1)

I was runnning on a set of Nitto NT-01 275/35/18's all round. They are nearing the end of their useful life, but still have a reasonable level of grip.

As an update, I ran a set of old PFC97pads cold on the rears for a day which cleaned off most of the brake deposit. Clean rear rotors showed some grooving and as they are a year plus old and have seen a lot of hot track days, I decided to machine them.

With the rears machined most of the vibration was gone. The rear disk surface may have been a factor in causing the rear pads to deposit so unevenly. There was still some vibration so the deposits on the new front stoptechs were still a factor.

Endless USA were consulted and I was advised not to machine the fronts but to bed them again using a 30x50mph to 10mph brake series using around 70% maximum pressure then usual cool down.

This is a lot gentler cycle than is generally recommended for high performance pads, but this is what Endless recommend. They say too high pedal pressure will cause these pads not to bed properly. I had to rebed the rear pads after machining anyway so I followed this routine today. The brakes do feel better. 99% of the vibration is gone, however the front rotors still show uneven deposits. I might try another gentle bedding sequence and see if this finally cleans up the fronts.

The issue then is I am back to where I started before the track sessions. Great feeling brakes which appear to bedded in. I have been told they really should be fine on the track, so as I have another track day in a weeks time I will give them a second chance. If I end up with the same problem I will give up on dual purpose pads.

MaddMatt

Material smearing like that is almost always a sign they went beyond their thermal capability.

Few questions: How do they feel now compared to before you took them to the track? What is the published range for those pads?

I suspect the same thing will happen at your next track day.

SteveA

iTrader: (1)

I agree with you. That was my first reaction. I could accept that the rear stock brembos may be struggling with handling the heat, but the new Stoptechs should have been fine providing the pads were operating in the right heat range.

These photos and comments were forwarded to Endless and they still seem to think the pads are fine and point to my bedding in procedure as a possible cause.

SteveA

iTrader: (1)

From the Endless Europe site:

CC-X
The CC-X is a high heat resistance compound which can also be used for circuit racing, like a sports car club race day. There is no need to change pads for such an event. The initial bite and response is excellent even at very high speed like 250-300 km/h and so also the pedal feel and brake balance.

Friction average: 0.35 - 0.45 µ
Temperature range: 100 - 700º (Celcius)

daytona350z

iTrader: (19)

this may be the cause of the overheating of the pads.

i personally run street tires on the track, rt-615's, and havent had any problems with my endless pads (CC-A).

the increased grip of your r-comps may just be too much for the pads, you would probably benefit from using cc-r pads for your use. the ccx are designed for a radil tire, vs the ccr for a s-tire (r)comp

SteveA

iTrader: (1)

You might be right. It's my fault for not researching the pads and relying on a supplier recommendation although I was very specific about my tires and type of track use. I have always used PFC01/97s for track and stock street pads in the past with no rotor problems, just overheating and brake fade. I had no experience with BBKs and I just assumed the Stoptechs would have so much better thermal capacity that a dual purpose pad would work fine.

MaddMatt: Does BHP sell a track pad for the St-60 caliper?

MaddMatt

ST60? No, unfortunately. Do they make an ST60 kit for the 350? I can't imagine you need that much.

We do have the ST40 pad though.

BTW, the friction coefficent of .35-.45 for those pads is not all that impressive....