Taking Street Car Brakes to the Track
10-10-2006, 10:14 PM
#1
Racer
Thread Starter
Taking Street Car Brakes to the Track
Hi guys,
I replied to a post regarding the management of street and race friction on another post the other week, and thought my response could benefit some of the trackhounds on this board. I edited somewhat, and thought this message was geared towards those who own a dual-use, daily driver / weekend warrior. Enjoy!
Typically a day or two before I go to the track, I put my race pads in. If you did a proper bed-in cycle on your street pads, you should have a transfer layer of street pad material on your rotors: http://www.stoptech.com/tech_info/wp...contents.shtml
Race pads are extremely abrasive when cold. Many are not designed to bite at low temperatures like street pads (although some will bite more than certain street compounds). Therefore, they will grind away on your rotors when driven cold. So, when you drive them around on the street before the event, they'll scrape all of the street pad material off of the rotors. You're then starting with a clean slate when you get to the track. This is important, because certain street and race compounds don't play very nice when they're together on the rotor face. They may stack, and cause minor thickness variations which you will realize as a judder or vibration. Also, if you leave a lot of street pad material on the rotor face when you heat them up to 1000+ deg. F on the track, the material will "glob up" when heated, and again potentially cause vibrations.
So, a night or two before the event, insert your race pads in the comfort of your own home. Drive your car as normal, but allow more stopping distance, particularly in the morning when they're cold. The pedal will feel hard, but the pads won't have much bite, and you're going to have to push a bit harder to get results. Just leave some room when coming to a stop.
If you do have a good street pad layer on your rotors, they probably won't make too much noise when you first put them in. They'll be riding on the street pad transfer layer that's on the rotors. By the time you get where you're going however, there's a good chance you'll hear a nice screeching noise from your brakes. That will happen when you wear through that pad layer, and get back to the bare rotor iron. Race pads typically have a high metallic content, so the metal in the pad and the iron of the rotor make some nice music together. Visually, it will also be obvious when you've 'cleaned' the rotors. Again, if you bed your street pads in properly, your rotors should have an even blue-gray tint to them on the swept area (which is the pad material transfer layer). After you've driven around on the race pads cold, the rotors will revert back close to their original silver color because they will no longer be covered in pad material.
Okay, so your race pads are in, you've gotten your rotors cleaned up, and you're ready for the track, right? No! When you get to the track, you need to bed-in your race pads properly per the instructions in my link above. You can do it during your first session at the track, or if you can legally and safely do it on a road near the track, that will also work. To get the pads heated up, you'll need to hit significantly higher speeds then you do with street pads, so 60-5mph won't really work. You're looking at a 100mph starting point. With the race pads hot, they'll go into their adherent mode, and transfer on to the rotor face when they're hot enough. Get a good bed-in cycle done on the pads, and then you're ready to go full blast on the track. Drive your event and have fun.
After the event is over, the car has cooled down, and your gear is all packed up, drive the car home on the race pads. The goal is the same as it was before the event, clean your rotors. Since the race pads will be cold again, they'll be back into their abrasive mode. They will scrape off the race pad material that you transferred onto the rotors. Many times, the rotors will be pretty clean by the time you get home...stop-and-go LA freeway traffic takes care of that for me. You can also do some light dragging of the pedal on the highway on the way home from the event to scrape them a bit...but you don't want to get them hot enough to leave their abrasive mode. If the rotors aren't clean when you get home, you can drive them around town a bit to clean them up.
Now the final phase to get your brakes peforming their best on the street again...swap your street pads back in. Do a bed-in cycle on the street pads to lay down some street pad material on the rotors. That's it!
Each pad compound is going to react differently. Some race compounds cold are insanely abrasive. Hawk Blue comes to mind. They will eat your rotors at an unprecedented rate. So, you may only want to run them on the drive to the track, not around town for days in advance. A Pagid RS14 Black however, will not be nearly as agressive. Also, each pad will have a certain temp at which they'll become adherent. You won't need to reach the same speeds to get them up to temp so they'll 'stick' to the rotor face. You'll just need to do some experimentation with the different compounds to see what you like, and the best way to manage them with your rotors.
Pad and rotor management is extremely important to get the most out of your brakes. I used the methods above on my last car with our BBK, and I did over a dozen events on one set of rotors without a single vibration. In summary, clean your rotors, bed-in, clean, bed-in, clean, etc. You should do a bed-in every time you change your pads, and the rotors should be free of the prior pad compound when you do so. If you do it right, you'll only ever have one pad compound on your rotor face at any given time. You will get some additional wear on the rotors when running the race pads cold, but it's worth the tradeoff. If you don't clean them up and bed-in properly, you run the risk of uneven pad depositions, judders, and sub-par performance (something you really don't want to be distracted by on the track). Also, if the pad deposits are too severe, they sometimes necessitate replacement of the rotor...which gets expensive in a hurry. Finally, most people that run our rotors on the track on a regular basis will crack them past the point of no return long before they will wear them thin. So, it's not worth worrying about the rotor thickness wear.
I think that's about it. Let me know if anyone has any questions. Be safe, leave extra stopping distance with cold race pads, do your bed-in's on safe stretches of tarmac, and have fun.
I replied to a post regarding the management of street and race friction on another post the other week, and thought my response could benefit some of the trackhounds on this board. I edited somewhat, and thought this message was geared towards those who own a dual-use, daily driver / weekend warrior. Enjoy!
Typically a day or two before I go to the track, I put my race pads in. If you did a proper bed-in cycle on your street pads, you should have a transfer layer of street pad material on your rotors: http://www.stoptech.com/tech_info/wp...contents.shtml
Race pads are extremely abrasive when cold. Many are not designed to bite at low temperatures like street pads (although some will bite more than certain street compounds). Therefore, they will grind away on your rotors when driven cold. So, when you drive them around on the street before the event, they'll scrape all of the street pad material off of the rotors. You're then starting with a clean slate when you get to the track. This is important, because certain street and race compounds don't play very nice when they're together on the rotor face. They may stack, and cause minor thickness variations which you will realize as a judder or vibration. Also, if you leave a lot of street pad material on the rotor face when you heat them up to 1000+ deg. F on the track, the material will "glob up" when heated, and again potentially cause vibrations.
So, a night or two before the event, insert your race pads in the comfort of your own home. Drive your car as normal, but allow more stopping distance, particularly in the morning when they're cold. The pedal will feel hard, but the pads won't have much bite, and you're going to have to push a bit harder to get results. Just leave some room when coming to a stop.
If you do have a good street pad layer on your rotors, they probably won't make too much noise when you first put them in. They'll be riding on the street pad transfer layer that's on the rotors. By the time you get where you're going however, there's a good chance you'll hear a nice screeching noise from your brakes. That will happen when you wear through that pad layer, and get back to the bare rotor iron. Race pads typically have a high metallic content, so the metal in the pad and the iron of the rotor make some nice music together. Visually, it will also be obvious when you've 'cleaned' the rotors. Again, if you bed your street pads in properly, your rotors should have an even blue-gray tint to them on the swept area (which is the pad material transfer layer). After you've driven around on the race pads cold, the rotors will revert back close to their original silver color because they will no longer be covered in pad material.
Okay, so your race pads are in, you've gotten your rotors cleaned up, and you're ready for the track, right? No! When you get to the track, you need to bed-in your race pads properly per the instructions in my link above. You can do it during your first session at the track, or if you can legally and safely do it on a road near the track, that will also work. To get the pads heated up, you'll need to hit significantly higher speeds then you do with street pads, so 60-5mph won't really work. You're looking at a 100mph starting point. With the race pads hot, they'll go into their adherent mode, and transfer on to the rotor face when they're hot enough. Get a good bed-in cycle done on the pads, and then you're ready to go full blast on the track. Drive your event and have fun.
After the event is over, the car has cooled down, and your gear is all packed up, drive the car home on the race pads. The goal is the same as it was before the event, clean your rotors. Since the race pads will be cold again, they'll be back into their abrasive mode. They will scrape off the race pad material that you transferred onto the rotors. Many times, the rotors will be pretty clean by the time you get home...stop-and-go LA freeway traffic takes care of that for me. You can also do some light dragging of the pedal on the highway on the way home from the event to scrape them a bit...but you don't want to get them hot enough to leave their abrasive mode. If the rotors aren't clean when you get home, you can drive them around town a bit to clean them up.
Now the final phase to get your brakes peforming their best on the street again...swap your street pads back in. Do a bed-in cycle on the street pads to lay down some street pad material on the rotors. That's it!
Each pad compound is going to react differently. Some race compounds cold are insanely abrasive. Hawk Blue comes to mind. They will eat your rotors at an unprecedented rate. So, you may only want to run them on the drive to the track, not around town for days in advance. A Pagid RS14 Black however, will not be nearly as agressive. Also, each pad will have a certain temp at which they'll become adherent. You won't need to reach the same speeds to get them up to temp so they'll 'stick' to the rotor face. You'll just need to do some experimentation with the different compounds to see what you like, and the best way to manage them with your rotors.
Pad and rotor management is extremely important to get the most out of your brakes. I used the methods above on my last car with our BBK, and I did over a dozen events on one set of rotors without a single vibration. In summary, clean your rotors, bed-in, clean, bed-in, clean, etc. You should do a bed-in every time you change your pads, and the rotors should be free of the prior pad compound when you do so. If you do it right, you'll only ever have one pad compound on your rotor face at any given time. You will get some additional wear on the rotors when running the race pads cold, but it's worth the tradeoff. If you don't clean them up and bed-in properly, you run the risk of uneven pad depositions, judders, and sub-par performance (something you really don't want to be distracted by on the track). Also, if the pad deposits are too severe, they sometimes necessitate replacement of the rotor...which gets expensive in a hurry. Finally, most people that run our rotors on the track on a regular basis will crack them past the point of no return long before they will wear them thin. So, it's not worth worrying about the rotor thickness wear.
I think that's about it. Let me know if anyone has any questions. Be safe, leave extra stopping distance with cold race pads, do your bed-in's on safe stretches of tarmac, and have fun.
10-10-2006, 11:33 PM
#3
Burning Brakes
Something that has worked for me is to use GM ceramic pads on the street and Carbotech pads (Panther Plus) on the track. The Carbotech track pads are ceramic based. I switch them freely with no prep and no problems so far for several years.
MD
MD
10-11-2006, 12:19 AM
#4
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Is there a special procedure if you swap both pads and rotors at home and then drive to the track? The pads are Carbotech XP8's, which I believe are relatively mild. I have yet to do any bedding.
Thanks,
Mike
Thanks,
Mike
10-11-2006, 07:52 AM
#5
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Carbotech Ceramic pads are MUCH differnt then GM or other Street ceramic brake pads.
Treat them as race pads.
Do the same bed in procedure as race pads.
Treat them as race pads.
Do the same bed in procedure as race pads.
Last edited by AU N EGL; 10-11-2006 at 07:56 AM.
10-11-2006, 10:00 AM
#7
Safety Car
Question: I f I have glazed my brakes. (They don't stop woth a crud anymore). Can I run a very aggressive road race pad cold, cleanthe rotors and then install new street pads? Or do I need to buy new rotors and pads?
10-11-2006, 10:54 AM
#8
Le Mans Master
This is good to know, but with all the other things to do in preparing for HPDE events, in my opinion this is totally impracticle. In the real world I would never find the time to do all this stuff. I run XP8's all summer and simply change my front pads at the track. I never feel glazing issues, or sloppy brakes and I go from street compounds right to full race compounds and my brakes work great. I find that I outbrake or match anyone on the track. I think this is probably (scientifically) the right way to go, but by no means is this necessary for strong and relaible braking at the track...just me $0.02
10-11-2006, 11:15 AM
#9
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Originally Posted by Red5
Question: I f I have glazed my brakes. (They don't stop woth a crud anymore). Can I run a very aggressive road race pad cold, cleanthe rotors and then install new street pads? Or do I need to buy new rotors and pads?
CLean the rotor with brake cleaner spay, wipe off the rotor and put on the track pads and rebed the rotors to those pads.
Rotors should be bedded with the same pad materail.
Plus full brake fluid flush before the event.
10-11-2006, 01:03 PM
#10
Burning Brakes
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good info - i saw this post elsewhere and posted a link a few days ago. for the guys that drive to the track with pads on, it doesn't sound like bedding makes much sense as it will be scrubbed off on the trip. all the more reason to take it easy on that first session.
10-11-2006, 05:51 PM
#11
Burning Brakes
Originally Posted by AU N EGL
Carbotech Ceramic pads are MUCH differnt then GM or other Street ceramic brake pads.
Treat them as race pads.
Do the same bed in procedure as race pads.
Treat them as race pads.
Do the same bed in procedure as race pads.
MD
10-11-2006, 06:21 PM
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Rotors should be bedded to the pads you use.
Some guys take the carbotech 8s for street driving then the 10s for the track and have no problem. That is fine.
Carbotech pads ( Personally I am not found of) have differnt braking charicteristics then Wilwood H, PFC01s, or 05s or Hawk DTC-70 pads.
Some guys take the carbotech 8s for street driving then the 10s for the track and have no problem. That is fine.
Carbotech pads ( Personally I am not found of) have differnt braking charicteristics then Wilwood H, PFC01s, or 05s or Hawk DTC-70 pads.
10-11-2006, 06:54 PM
#13
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Originally Posted by AU N EGL
Carbotech pads ( Personally I am not found of) have differnt braking charicteristics then Wilwood H, PFC01s, or 05s or Hawk DTC-70 pads.
If I had my druthers, I would be using DTC-70s.
Frank Gonzalez
10-12-2006, 07:53 PM
#15
Melting Slicks
Jeff at Stoptech:
Are there any published reports on the coefficient of friction for different types of pad compounds? Most manufacturers don't publish that data. How can you balance your brake system if you don't know the frictional force of the pad, unless you use the same pad compound front and rear. I look forward to your comment and data, if you have it.
Are there any published reports on the coefficient of friction for different types of pad compounds? Most manufacturers don't publish that data. How can you balance your brake system if you don't know the frictional force of the pad, unless you use the same pad compound front and rear. I look forward to your comment and data, if you have it.
10-13-2006, 12:25 AM
#16
Racer
Thread Starter
Sidney,
We do have our own estimates of the coefficient of friction of the pads (mu). We are able to test on a dyno in a controlled environment. Manufacturers publish numbers, but I wouldn't recommend blindly following those numbers.
Also, you have to realize that Mu is going to be all over the map at different temperatures. Therefore, it's not a constant.
We test all of our kits at the track with the friction we ship in the kits. That's how we get the balance optimized. Now, if you change to a pad with a different Mu, that's going to take you to a slightly different balance. Some cars are more sensitive to this than others. The goal however is to get to the proper starting point with piston sizing. For example, competitors' systems that are already too far front biased, are even worse off when you through a high Mu race friction on the front. In other words, they diverge further from ideal.
So again, the goal is to get in the proper range, that allows enough latitude to dial the car in to your preferred feel with friction if you want to do so. There is no 'perfect' balance per se however.
We do have our own estimates of the coefficient of friction of the pads (mu). We are able to test on a dyno in a controlled environment. Manufacturers publish numbers, but I wouldn't recommend blindly following those numbers.
Also, you have to realize that Mu is going to be all over the map at different temperatures. Therefore, it's not a constant.
We test all of our kits at the track with the friction we ship in the kits. That's how we get the balance optimized. Now, if you change to a pad with a different Mu, that's going to take you to a slightly different balance. Some cars are more sensitive to this than others. The goal however is to get to the proper starting point with piston sizing. For example, competitors' systems that are already too far front biased, are even worse off when you through a high Mu race friction on the front. In other words, they diverge further from ideal.
So again, the goal is to get in the proper range, that allows enough latitude to dial the car in to your preferred feel with friction if you want to do so. There is no 'perfect' balance per se however.
10-13-2006, 01:14 AM
#17
Burning Brakes
Originally Posted by Sidney004
Jeff at Stoptech:
Are there any published reports on the coefficient of friction for different types of pad compounds? Most manufacturers don't publish that data. How can you balance your brake system if you don't know the frictional force of the pad, unless you use the same pad compound front and rear. I look forward to your comment and data, if you have it.
Are there any published reports on the coefficient of friction for different types of pad compounds? Most manufacturers don't publish that data. How can you balance your brake system if you don't know the frictional force of the pad, unless you use the same pad compound front and rear. I look forward to your comment and data, if you have it.
Z06. My point being that putting the same pads all around, does not guarantee you a factory front to back balance...
MD
10-13-2006, 06:58 AM
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Originally Posted by AU N EGL
Rotors should be bedded to the pads you use.
Some guys take the carbotech 8s for street driving then the 10s for the track and have no problem. That is fine.
Carbotech pads ( Personally I am not found of) have differnt braking charicteristics then Wilwood H, PFC01s, or 05s or Hawk DTC-70 pads.
Some guys take the carbotech 8s for street driving then the 10s for the track and have no problem. That is fine.
Carbotech pads ( Personally I am not found of) have differnt braking charicteristics then Wilwood H, PFC01s, or 05s or Hawk DTC-70 pads.
10-13-2006, 08:05 AM
#19
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Originally Posted by Juha
Do you know is Wilwood H's material corrosive just like Hawk's material is?
No the Wilwood H material is not carrosive. the H materail has a high inital bite and holds that bit or grip for very high temps.
H pad are not a good choice to drive to and from the event. The have poor inital bit at cold temps of normal street driving.
That being said one could put on the race pads and drive to and from the track, just realize your brakes will not be there best at cold temps and brake accordingly.
SOme thing else Jeff brought up earler or in an other thread is and drivers braking style. Yes we all know to brake hard at first then ease off, as we enter the trun in point. Plus the type of race, endurance racing, which most of us we never experience, or sprint racing and in most cases just doing track days.
10-13-2006, 01:52 PM
#20
Racer
Thread Starter
My understanding the new Hawk DTC-60s and 70s are not as corrosive as the old Hawk Blues or Blacks.
The DTC70's are indeed a LOT less harsh than the Blue's. The Blues will leave a pile of rust on your wheels with the introduction of any moisture. You need to get that dust off your wheels asap with those pads. The DTC70's dust is moderate for a race pad, and not nearly as adherent or harsh.
I don't have any experience with the Blacks.
Last edited by J Ritt; 10-13-2006 at 01:55 PM.