I have a spare set of napa rotors that I take to the track with me, however with all of the talk lately about proper breaking in of rotors how should I do it? Should I put all 4 on the car, heat them up at home on some backroads, then take them off so they are ready to use when I need them at the track? If I wait until I get to the track when I need them I wont have 24 hours to let them cool and such. what do the racers here do?
bedding in rotors
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I put them on and bed them before I get to the track.
Several short stops then increase speeds and stop, then highway and a few hard stops
Bedding is usually done for race pads before track sessions. You want to transfer some pad material to the surface of the rotor and outgas some of the binder at the surface to prevent green fade on the track. You want to get the rotors and pads up to racing temp gradually to avoid cracking the rotors.
I am sure other will chime in :cheers:
Several short stops then increase speeds and stop, then highway and a few hard stops
Bedding is usually done for race pads before track sessions. You want to transfer some pad material to the surface of the rotor and outgas some of the binder at the surface to prevent green fade on the track. You want to get the rotors and pads up to racing temp gradually to avoid cracking the rotors.
I am sure other will chime in :cheers:
The first step in preparing the brake system for duty is to "SEASON" the rotors. The most visible effects are that of burning the machine oils from the surface of the iron and establishing a wear pattern between the pad and rotor. The most complex task it performs is that of relieving the internal stresses within the material. If you've ever poured water into a glass of ice, and noticed the ice cracking, then you've witnessed, first hand, the effects of internal stresses. The rotor casting and cooling processes leave the rotor with internal stresses.
By gradually heating the material, the crystalline matrix will reconfigure to relieve these internal stresses. 0nly after these stresses are relieved, is the rotor is ready to accept the heat of bedding pads or race speeds. Heating the rotors before they are fully seasoned can result in material deformation clue to the unrelieved internal stresses in the material. This deformation may cause a vibration from the brakes.
After initial bedding, race drivers should use the first lap of a session, to warm the brakes as well as the engine, gearbox, etc. Where an engine turns chemical energy into motion, the brakes turn that motion into thermal energy……and lots of it! And where there is no cooling system for the brakes as there is for the engine, and there's not, the brakes could use the courtesy of a warm-up lap.
Seasoning procedure:
1)Before you begin, please note: The following is a condensed version of of the "Seasoning" process designed for racing, where rotors are often replaced after every event.. If your situation offers any opportunity to perform the Seasoning for Street and/or -Light Track Event ApplicaUons outlined on a separate instruction set (enclosed for reference), please do so. The most noticeable result of this care will be dramatically increased long term rotorlife. Top professional teams believe this to be the case and invest heavily in pre-burnishing or "Seasoning" services. The same service Baer offers and recommends for racers.
2) Temporarily close or restrict any cooling ducts provided for the brakes. Note: New rotors should be "Seasoned" with used pads. If you are "Seasoning" a completely new system, this Is not an alternative, so take extra care in the "Seasoning"' procedure. Most likely, you will begin "bedding" the pads in the latter stages of the procedure. It is still recommended that you follow the separate Preparing your Brake System: Bedding Pads procedures or invest in the pre-burnishing "Seasoning" service.
3) Make several light stops from 30 mph to ensure brake system is functioning properly (good pedal, no leaks, etc.).
4) Gradually increase brake temperatures with progressively harder, faster, stops (the key here.is to make the temps rise steadily, however - NEVER DRAG THE BRAKE).
5) Continue the process, through 10-15 stops, steadily increase braking forces until the rotors have reached full operational temperature; about 1100° E Note: Accurate temperature paints may be obtained from Baer Racing.
6) Allow the brakes to cool, as gradually as possible, by driving easily for 10 minutes or so. The idea is to cool the brake system to ambient. Given the opportunity, let the system cool off over night.
7)Reopen your cooling ducts. The rotors- are now ready for the next step in Preparing your Brake System:Bedding Pads
Racers should "Season" a couple sets of rotor. In the event that one needs to be replaced during a race, it should only be replaced with a"Seasoned" rotor. We strongly advise against racing on a "green" rotor. The thermal shock and unrelieved internal stresses can crack, break or even explode a "green" rotor! Additionally, race cars need a cool down lap before parking a car that has been run at speed. Avoid sitting on pitlane after a session or during a pit stop with your foot on the brake unless conditions absolutely require such. In the pits it is advised to roll the car back and forth, when the brakes are hot, to avoid internal stresses from uneven cooling of the rotor due the shrouding effect of the caliper and its heat.
By gradually heating the material, the crystalline matrix will reconfigure to relieve these internal stresses. 0nly after these stresses are relieved, is the rotor is ready to accept the heat of bedding pads or race speeds. Heating the rotors before they are fully seasoned can result in material deformation clue to the unrelieved internal stresses in the material. This deformation may cause a vibration from the brakes.
After initial bedding, race drivers should use the first lap of a session, to warm the brakes as well as the engine, gearbox, etc. Where an engine turns chemical energy into motion, the brakes turn that motion into thermal energy……and lots of it! And where there is no cooling system for the brakes as there is for the engine, and there's not, the brakes could use the courtesy of a warm-up lap.
Seasoning procedure:
1)Before you begin, please note: The following is a condensed version of of the "Seasoning" process designed for racing, where rotors are often replaced after every event.. If your situation offers any opportunity to perform the Seasoning for Street and/or -Light Track Event ApplicaUons outlined on a separate instruction set (enclosed for reference), please do so. The most noticeable result of this care will be dramatically increased long term rotorlife. Top professional teams believe this to be the case and invest heavily in pre-burnishing or "Seasoning" services. The same service Baer offers and recommends for racers.
2) Temporarily close or restrict any cooling ducts provided for the brakes. Note: New rotors should be "Seasoned" with used pads. If you are "Seasoning" a completely new system, this Is not an alternative, so take extra care in the "Seasoning"' procedure. Most likely, you will begin "bedding" the pads in the latter stages of the procedure. It is still recommended that you follow the separate Preparing your Brake System: Bedding Pads procedures or invest in the pre-burnishing "Seasoning" service.
3) Make several light stops from 30 mph to ensure brake system is functioning properly (good pedal, no leaks, etc.).
4) Gradually increase brake temperatures with progressively harder, faster, stops (the key here.is to make the temps rise steadily, however - NEVER DRAG THE BRAKE).
5) Continue the process, through 10-15 stops, steadily increase braking forces until the rotors have reached full operational temperature; about 1100° E Note: Accurate temperature paints may be obtained from Baer Racing.
6) Allow the brakes to cool, as gradually as possible, by driving easily for 10 minutes or so. The idea is to cool the brake system to ambient. Given the opportunity, let the system cool off over night.
7)Reopen your cooling ducts. The rotors- are now ready for the next step in Preparing your Brake System:Bedding Pads
Racers should "Season" a couple sets of rotor. In the event that one needs to be replaced during a race, it should only be replaced with a"Seasoned" rotor. We strongly advise against racing on a "green" rotor. The thermal shock and unrelieved internal stresses can crack, break or even explode a "green" rotor! Additionally, race cars need a cool down lap before parking a car that has been run at speed. Avoid sitting on pitlane after a session or during a pit stop with your foot on the brake unless conditions absolutely require such. In the pits it is advised to roll the car back and forth, when the brakes are hot, to avoid internal stresses from uneven cooling of the rotor due the shrouding effect of the caliper and its heat.
Carbotech recommends 4-6 moderate brake applications from about 50 mph to 30 mph followed by 4-6 hard brake applications from about 60 mph to about 5 mph followed by a 30 minute cool down. For heavy cars such as ours (that is a relative term compared to most racecars), they also recommend a moderate first session using only about 70% of the brakes for about six laps followed by one hard lap and then 30 minute cool down.
I have done the bedding both on the back roads and during my first track session at a track. I prefer to have it done before I go to the track. I generally take the first session easy whether the rotors/pads have been bedded or not, but it gives me extra confidence to have it done beforehand. However, this isn't always practical. :cheers:
I have done the bedding both on the back roads and during my first track session at a track. I prefer to have it done before I go to the track. I generally take the first session easy whether the rotors/pads have been bedded or not, but it gives me extra confidence to have it done beforehand. However, this isn't always practical. :cheers:
Bedding Rotors for the Track
I'm curious to learn if those who change rotors for track days also install new spindle bolts that hold each of the calipers? These are 21 mm Grade 10.9 bolts that GM's manual states ARE NOT TO BE REUSED. A 4 rotor change requires 8 new bolts and these bolts aren't cheap. They are torqued to 125 lb-ft and that can take some serious effort if you don't have adequate leverage. Also, if you change back to "street" rotors after a track day, that means you will use 16 of these bolts for every track day!
Does anyone really do this or do you just reuse the bolts in spite of the warning?
Does anyone know who sells these bolts other than GM dealers? Hopefully for much cheaper?
Thanks
I'm curious to learn if those who change rotors for track days also install new spindle bolts that hold each of the calipers? These are 21 mm Grade 10.9 bolts that GM's manual states ARE NOT TO BE REUSED. A 4 rotor change requires 8 new bolts and these bolts aren't cheap. They are torqued to 125 lb-ft and that can take some serious effort if you don't have adequate leverage. Also, if you change back to "street" rotors after a track day, that means you will use 16 of these bolts for every track day!
Does anyone really do this or do you just reuse the bolts in spite of the warning?
Does anyone know who sells these bolts other than GM dealers? Hopefully for much cheaper?
Thanks
The same bolts that came stock on my car are still in there. I've changed rotors probably 75+ times on my car over the past 5 years and never changed those bolts. I've never seen one fail either. If it makes you feel better, you could swap them once a year, but you really don't need to.
I've read that the basis for the GM recommendation to use new bolts is that the new bolts come with red locktite on them. I use the old bolts and put red locktite on them.
I usually change out these bolts once a year, but reuse them dozens of times during a race season. :cheers:
I usually change out these bolts once a year, but reuse them dozens of times during a race season. :cheers:
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