Cracking Rotors
#16
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I always feel like the odd man out on this topic...
I've had times when I had to change pads in between run groups (hey, when you have two people driving the car at the Glen, you'll go through pads). With the time constraints, I didn't have a lot of chance to bed in the new pads, and I didn't notice a bit of difference. Since then, I'll try to bed in pads if I have the chance, but it's not something that I view as a "must do" kind of thing. I'm using Pagid Oranges, maybe other manufacturers require a bedding process.
As far as braking harder/lighter and its effect on pad usage, I've noticed that the moment I started braking lighter, my pads started lasting nearly twice as long. Now, some if that improved pad wear is that I'm actually braking less and carrying more speed into the turns.
I never had a spongy brake problem with either sort of braking provided that I did good brake maintenance prior to the event. In other words, make sure to change the brake fluid regularly and bleed before every event. The times that I've skipped that are the times that I've noticed a spongy brake feeling. I tend to completely flush the brake fluid about three times a year now.
I've had times when I had to change pads in between run groups (hey, when you have two people driving the car at the Glen, you'll go through pads). With the time constraints, I didn't have a lot of chance to bed in the new pads, and I didn't notice a bit of difference. Since then, I'll try to bed in pads if I have the chance, but it's not something that I view as a "must do" kind of thing. I'm using Pagid Oranges, maybe other manufacturers require a bedding process.
As far as braking harder/lighter and its effect on pad usage, I've noticed that the moment I started braking lighter, my pads started lasting nearly twice as long. Now, some if that improved pad wear is that I'm actually braking less and carrying more speed into the turns.
I never had a spongy brake problem with either sort of braking provided that I did good brake maintenance prior to the event. In other words, make sure to change the brake fluid regularly and bleed before every event. The times that I've skipped that are the times that I've noticed a spongy brake feeling. I tend to completely flush the brake fluid about three times a year now.
#17
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Bill,
I've been through exactly what you mention. I've found that the the S4 rotors are help because they are more massive. Skip the ones with holes & go slotted or just solid. You can put the S4s on your car you have to mill down the hubs so they'll fit inside the diameter of the late offset rotors but the result is worth the work.
Good Luck.
I've been through exactly what you mention. I've found that the the S4 rotors are help because they are more massive. Skip the ones with holes & go slotted or just solid. You can put the S4s on your car you have to mill down the hubs so they'll fit inside the diameter of the late offset rotors but the result is worth the work.
Good Luck.
#19
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I don't mean to start a war here but,
Braking harder at the beginning of the brake zone seems to be better brake management because this is when the cooling effect of rushing air is greatest, and since the brake system is coolest at the beginning of the brake zone, this is when they are able to do the most work. Then trailing off the brakes as the zone ends puts less heat into the system when air cooling is less.
I believe the graduated approach is better than the continous medium effort approach.
Braking harder at the beginning of the brake zone seems to be better brake management because this is when the cooling effect of rushing air is greatest, and since the brake system is coolest at the beginning of the brake zone, this is when they are able to do the most work. Then trailing off the brakes as the zone ends puts less heat into the system when air cooling is less.
I believe the graduated approach is better than the continous medium effort approach.
#20
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I'm kind of surprised my comments didn't degrade into another personal attack fest .. hmm.
OK, now that we argree that overall temps are not affected by braking style, pad life is. The higher the peak temps, the more pad wear you will experince. So, if you are trying to preserve your pads, you can brake longer and softer, but if you are overheating, the only thing you can do is slow down (brake less).
OK, now that we argree that overall temps are not affected by braking style, pad life is. The higher the peak temps, the more pad wear you will experince. So, if you are trying to preserve your pads, you can brake longer and softer, but if you are overheating, the only thing you can do is slow down (brake less).
#21
Burning Brakes
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One of the things we've figured out, running long endurance races, is how to minimize brake maintenance issues. Brake pad changes are a slow PITA, and we try to avoid them as much as possible.
How to make your pads live longer ? Minize the "big heavy foot" at the beginning of the brake zone. Squeeze'em on slowly, to avoid a sudden temperature spike. Make that temperature rise a slow ramp, rather than a sharp leading edge. How much slower in the application ? Well...in actuality...not that much slower. If you're a noob, you probably couldn't even feel the difference. We're talking about a 'nuanced' application here, not a dramatic change in braking technique. We have night-time pix of our cars with the brake rotors lit up like roman candles, and we're still getting good brake pad life.
How much of a difference does it make ? Measured by laps or hours...we can stretch brake pad life by 15-30%. Two 24-hour and six 12-hour class wins say "We have a clue about this".
Original question about rotors ? They're just as disposable as brake pads. Throw'em away regularly. Are they deep cracks, or just very fine surface spider cracks ? Surface cracks are normal, but when they start opening up, introduce those rotors to the garbage can.
How to make your pads live longer ? Minize the "big heavy foot" at the beginning of the brake zone. Squeeze'em on slowly, to avoid a sudden temperature spike. Make that temperature rise a slow ramp, rather than a sharp leading edge. How much slower in the application ? Well...in actuality...not that much slower. If you're a noob, you probably couldn't even feel the difference. We're talking about a 'nuanced' application here, not a dramatic change in braking technique. We have night-time pix of our cars with the brake rotors lit up like roman candles, and we're still getting good brake pad life.
How much of a difference does it make ? Measured by laps or hours...we can stretch brake pad life by 15-30%. Two 24-hour and six 12-hour class wins say "We have a clue about this".
Original question about rotors ? They're just as disposable as brake pads. Throw'em away regularly. Are they deep cracks, or just very fine surface spider cracks ? Surface cracks are normal, but when they start opening up, introduce those rotors to the garbage can.
#22
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Formulate and conceptualize all you want...
- When I brake long and light, I get ZERO rotor wear.
- When I tried short and hard, my pads glazed and my rotors cracked.
I think I know which style causes more stress... and works best for me.
- When I brake long and light, I get ZERO rotor wear.
- When I tried short and hard, my pads glazed and my rotors cracked.
I think I know which style causes more stress... and works best for me.
#23
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I've always been told to make my brake pedal applications firm and deliberate but not sudden. That is, brake hard and smoothly but don't stomp on them. THEN ease off as you approach the speed you want.
#24
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I can agree with all of this. I also replaced my stock drilled rotors with slotted rotors that generally hold up much better. No stress concentration, no ridging on the rotors due to temp differences caused by the holes, etc.
#25
Nordschleife Master
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Hard agressive braking heats the rotors more suddenly which creates bigger temperature differences across the rotor. That causes cracking. The hgiher forces wears pads and rotors more quickly. It is also a faster way around the track then longer slower braking. Your choice!
#26
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Originally Posted by GlenL
Hard agressive braking heats the rotors more suddenly which creates bigger temperature differences across the rotor. That causes cracking. The hgiher forces wears pads and rotors more quickly. It is also a faster way around the track then longer slower braking. Your choice!
I believe it's FAR easier to overbrake a turn with the quick, hard braking style. As such, it causes you to be slower overall. Granted, if you are really, really good, you can brake short and quick and brake down to the right speed.
#27
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Well, I am persuaded. I will try to be more progressive getting on the brakes. After all, if you're pouring hot liquid into a glass, do it slowly, particularly at the beginning.
Thanks, forum.
Bill
Thanks, forum.
Bill
#28
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Brian's in the right track, as it were.
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The popular myth is to "accelerate till you see God, then brake like the Devil." That is actually quite a missconception, and a disservice to novice drivers. It takes years sometimes to break that habit. What seems fast - when the brain is in overload - is usually very slow, and often completely unnecessary. It is only the brain of the driver going rapidly, not his car.
The length of the acceleration zone largely determines top speed. Carrying more speed into the corners obviously tranlsates to more terminal velocity. Most people don't carry nearly as much corner speed as they could. If they are looking in their mirrors, and thinking, I prove that to them at every track event!![Stick Out Tongue](https://rennlist.com/forums/images/smilies/tongue.gif)
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It occurs to me that most things in life do not like to be shocked or brutalized. Why would brakes be any different? Metal does not like to be shocked by temperature extremes. When it is, it usually gets brittle. When you temper metal, you slowly heat it to a known temperature, then slowly let it cool. Braking should not be any different, it seems to me. When it does exceed the comfort range of the metal, a range it is not used to, the metal protests!
Bill, my theory is that rotors that were used to a certain temperature range were shocked by the increased clamping force (and therefor heat) of the larger calipers. You exceeded their known and familiar comfort zone. Just as I shocked my perfectly good rotors by changing braking styles. We should have been more gentlemanly!
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The popular myth is to "accelerate till you see God, then brake like the Devil." That is actually quite a missconception, and a disservice to novice drivers. It takes years sometimes to break that habit. What seems fast - when the brain is in overload - is usually very slow, and often completely unnecessary. It is only the brain of the driver going rapidly, not his car.
The length of the acceleration zone largely determines top speed. Carrying more speed into the corners obviously tranlsates to more terminal velocity. Most people don't carry nearly as much corner speed as they could. If they are looking in their mirrors, and thinking, I prove that to them at every track event!
![Stick Out Tongue](https://rennlist.com/forums/images/smilies/tongue.gif)
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It occurs to me that most things in life do not like to be shocked or brutalized. Why would brakes be any different? Metal does not like to be shocked by temperature extremes. When it is, it usually gets brittle. When you temper metal, you slowly heat it to a known temperature, then slowly let it cool. Braking should not be any different, it seems to me. When it does exceed the comfort range of the metal, a range it is not used to, the metal protests!
Bill, my theory is that rotors that were used to a certain temperature range were shocked by the increased clamping force (and therefor heat) of the larger calipers. You exceeded their known and familiar comfort zone. Just as I shocked my perfectly good rotors by changing braking styles. We should have been more gentlemanly!
#30
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I think the concensous is: drive slower if you want your car parts to last longer. Now management of the car while still being fast....... that's another point. I have my techniques and, hopefully, so do the rest of you. This is always a topic of discussion at the track. I only know that as I have improved, my brakes last longer (as does the rest of the car). But I still go through pads like crazy.