Gregg:
Man, I did not see this picture before. That is nasty! You were using Panther XPs? Do you think they are too harsh? Or was it just worn rotors?

That is pretty bad, how did it feel on the track?

 

Nasty!

 

I think that can be attributed to my failure to do preventive maintenance. The rotors were quite worn prior to moving to the XP's and should have been replaced a while ago. Notice those neat little fissures??? They popped up about three track days ago and guess who ignored them?

 

Rotors are just consumable items when it comes to track use.. even with cryo treatment some teams can't make them last more than several events. Cracks like that come from extreme heating and may have started with a weak spot and heavy use many events ago.

 

Gregg,

I have the same cracks on my front rotors using Panther XP's. These pads are fantastic - they are so good that their fade resistance exceeds the rotors temperature limits. I think what happened to me was that the brakes were not fading under really hard braking because of the XP's, and I continued to brake hard throughout the track session and overheated the rotors.

I spoke to CarboTech. They said that you MUST let the rotors cool down before you park the car because the rotors can become even hotter with the XP's. The part of the rotor trapped under the pads will stay hot while the exposed portion cools, leading to alot of thermal stress and eventually cracking.

 

Thanks a bunch, Nick. I usually take a lil' stroll along the paddock before parking but it looks like I'll have to be a bit (ok, a lot) more careful.

 

Yes, preventive medicine is a very good phrase for this...you should always check your equipment, from top to bottom, before stepping foot on a track.

It is normal for traditional rotors to develop superficial/surface spider-web type cracking on the rotor face after repeated high heat cycles. The cracks result from thermal expansion and cooling. Regardless of the pad compound you choose to use, it is always important to promote even/uniform and gradual cooling to the brake system components via 1 or 2 good cool down laps, where you are really just coasting around the track and not using the brakes. After you get into the paddock, it is also a good idea to do a couple laps in the paddock area before you park the car - do NOT use your e-brake when you park...just leave it in gear and shut the car off.

From the picture, it appears to me that the rotor is very worn...you have a lip on the inside near the rotor hub, as well as on the outside edge of the rotor. Your rotor may not have even been within factory spec for thickness while you were using it. I cannot stress enough that we all need to inspect our equipment...your lives depend on it! Also, you will see in the picture that the largest (longest) crack also begins to extend into the hub area of the rotor itself...very dangerous. As a rule of thumb, if you have any single crack that is longer than 5/8" and more than 0.010" in width OR you are within 15% of the manufacturer's spec for rotor thickness (i.e. discard thickness) before a track event...replace the rotor.

An an aside, I had one customer recently who ran rotors which were too thin (below factory spec), and coming into a hard braking zone, the right front shattered into 4 pieces...all that was left of the rotor was the hub itself, which was still bolted on between the spindle and the wheel...but the rotor itself had shattered into several pieces...he had to go back onto the track to pick up the pieces. Upon further inspection, he found that the front left rotor wasn't far behind...so be vigilent about maintaining your vehicle systems. Needless to say, he went off the track into the weeds...luckily, there was NOT a wall there...imagine if there was: you are going 135mph, and expect to decellerate to 45mph to make a sharp turn...but are still going 90mph when you hit the edge of the tarmac...

With Best Regards,

Andie Lin (formerly CarbotechAndie, now "cobalt")
Principal - Operations and Product Development
Cobalt Friction Technologies - an Ecocomp Partner Company
E-mail: andiewlin@yahoo.com

 

So there you are!!

Nice to see you back here, Mr. Brake expert!!

So let us know what your cooking up this time!

 

Well, as many of you know, I have left Carbotech for a myriad of issues, but have started my own brake technology company called COBALT FRICTION TECHNOLOGIES. My new business partners share my same enthusiasm for motorsports and overall business philosophy.

We are in the process of designing new brake compounds for various applications, including: (1) high-performance street, (2) Solo-2 auto-x, (3) Solo-1 auto-x, (4) road racing, (5) drag racing, (6) rally racing, and (7) formula car applications, in a wide variety of fitments - both OEM and for aftermarket caliper systems.

Our compounds for street and weekend track use will feature: (1) strong initial bite, (2) excellent cold stopping, (3) lower dust and noise levels than other competing products, (4) rotor friendly wear, (5) excellent pad wear rates. These are the primary issues I am focusing on and plan to address with our new product line; the feedback I have received from my customers while at Carbotech indicate that these are important points.

Our race compounds will have much less stress on the "aesthetic" issues of noise and dust levels (for obvious reasons), but will have market leading initial bite, yet have good modulation, excellent wear rates, be rotor friendly, and a fade resistance point upwards of 1400F.

The most important sets of information we will be using to develop our products are the feedback I have received from customers. It is my goal to deliver to the market exactly what people want and ask for, rather than what we can sell. In other words, I want to make what people want us to sell, rather than sell what we can make. Given the high level of technical resources from within the friction compound industry that we have, designing such products successfully will not be a problem.

We will also carry products from Hawk, Performance Friction, the Axxis Ultimate, Brembo, etc. For brake fluid, we will have Motul RBF 600, AP Racing 600, Castrol SRF, ATE Superblue and Typ200, and our own brand of racing brake fluid which has lab-tested to have higher wet and dry boiling points than Motul RBF 600!

As always, I greatly appreciate the support I have received from my Honda/Acura customers, especially the S2000 owners! Your loyalty has played a significant role in making my present business plans a reality!

Stay tuned!

Andie Lin
Cobalt Friction Technologies

 

Andie, good luck with your new venture. Please let us know when you have the first product for the S2000. Many on this board have benefited from your advice and with your new venture, I hope you will continue to provide good technical information.