Drilled / Slotted Brake Rotors - Benefit of Chamfered over Non-Chamfered holes?
03-12-2006, 04:03 PM
#1
Drifting
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Drilled / Slotted Brake Rotors - Benefit of Chamfered over Non-Chamfered holes?
Is there a benefit to having chamfered holes on drilled / slotted rotors over drilled / slotted rotors without chamfered holes?
03-12-2006, 05:22 PM
#3
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No difference what so ever camfered not camfered, drilled or cast in holes.
Some companies make the rotors that have the holes cast into the rotor, Porsche, MB and Brembo Italia ( not Brembo NA - ) vs most are drilled
In theroy that was to lighten the rotors and out gass the aspestous gases from the aspetus brake pads. But aspestous brake pads were last used in the 1960s.
The holes get filled up with brake dust so not used for cooling.
in short a 40 year old technology kept around only for marketing purposes as customers want them.
Some companies make the rotors that have the holes cast into the rotor, Porsche, MB and Brembo Italia ( not Brembo NA - ) vs most are drilled
In theroy that was to lighten the rotors and out gass the aspestous gases from the aspetus brake pads. But aspestous brake pads were last used in the 1960s.
The holes get filled up with brake dust so not used for cooling.
in short a 40 year old technology kept around only for marketing purposes as customers want them.
03-12-2006, 05:41 PM
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St. Jude Donor '03-'04
There is absolutely a difference in chamfers....
when holes are drilled at 90 degrees to the fire path, the sharp 90 degree corner creates a "HOT Spot" these corners get 30% hotter than the rest of the rotor. This is cause by angular stress over variable planes. its the effect of drilling that cause the molecules to move closer together at the corners which causes this stress. When stress is relieved or equal , all the molecules are the same distance apart...
A 45 degree chamfer reduces the angular plane thus reducing the Hot spot, so internal stress is less, and this helps with cracking at the angles...no sharp corners
Better than a 45 degree champer is something called a sinus chamfer,
it is a radial chamfer, meaning it doesn't not have a flat plane.. there is little or no Hot spot with a sinus chamfer. So internal stress across the total plane is equal, so when they expand and contract, they do it at the same rate, because there are no hot spots... Casted holes do the same thing... because there are differences in the stress between surface and holes...the whole rotor expands and contracts at the same rate...
Straight Drilled Hole ------------------->
A high stress and heat build up area forms at the intersection of the rotor and drilled edge.
Countersunk Hole ----------------------->
Countersinking increases the external surface area of the hole, thus reducing heat, but still contains edges prone to stress and heat build up.
Radius Hole -------------------------------->
The Radius Chamfer increases the hole cooling area thus reducing heat, but still contains sharp edges.
SP* Sinusoidal Curved and Chamfered Hole ----------------------->
Absolutely no sharp edges. The smooth design promotes cooling and minimizes stress, reducing the possibility of heat checking while increasing both rotor and pad life.
The Sinus-Curve is an example of a design inspired by mathematical principles. Although this process is well known in the industry, it is costly, but it is perfect for those wanting bling for their street car with some spirited braking...
My Eradispeed rotors have sinusoidal chamfers... Not a Baer application, I did them myself...
I hope the pictures make this clearer
Bill aka ET
when holes are drilled at 90 degrees to the fire path, the sharp 90 degree corner creates a "HOT Spot" these corners get 30% hotter than the rest of the rotor. This is cause by angular stress over variable planes. its the effect of drilling that cause the molecules to move closer together at the corners which causes this stress. When stress is relieved or equal , all the molecules are the same distance apart...
A 45 degree chamfer reduces the angular plane thus reducing the Hot spot, so internal stress is less, and this helps with cracking at the angles...no sharp corners
Better than a 45 degree champer is something called a sinus chamfer,
it is a radial chamfer, meaning it doesn't not have a flat plane.. there is little or no Hot spot with a sinus chamfer. So internal stress across the total plane is equal, so when they expand and contract, they do it at the same rate, because there are no hot spots... Casted holes do the same thing... because there are differences in the stress between surface and holes...the whole rotor expands and contracts at the same rate...
Straight Drilled Hole ------------------->
A high stress and heat build up area forms at the intersection of the rotor and drilled edge.
Countersunk Hole ----------------------->
Countersinking increases the external surface area of the hole, thus reducing heat, but still contains edges prone to stress and heat build up.
Radius Hole -------------------------------->
The Radius Chamfer increases the hole cooling area thus reducing heat, but still contains sharp edges.
SP* Sinusoidal Curved and Chamfered Hole ----------------------->
Absolutely no sharp edges. The smooth design promotes cooling and minimizes stress, reducing the possibility of heat checking while increasing both rotor and pad life.
The Sinus-Curve is an example of a design inspired by mathematical principles. Although this process is well known in the industry, it is costly, but it is perfect for those wanting bling for their street car with some spirited braking...
My Eradispeed rotors have sinusoidal chamfers... Not a Baer application, I did them myself...
I hope the pictures make this clearer
Bill aka ET
Last edited by Evil-Twin; 03-12-2006 at 06:07 PM.
03-12-2006, 06:24 PM
#5
Safety Car
Originally Posted by Evil-Twin
There is absolutely a difference in chamfers....
when holes are drilled at 90 degrees to the fire path, the sharp 90 degree corner creates a "HOT Spot" these corners get 30% hotter than the rest of the rotor. This is cause by angular stress over variable planes. its the effect of drilling that cause the molecules to move closer together at the corners which causes this stress. When stress is relieved or equal , all the molecules are the same distance apart...
A 45 degree chamfer reduces the angular plane thus reducing the Hot spot, so internal stress is less, and this helps with cracking at the angles...no sharp corners
Better than a 45 degree champer is something called a sinus chamfer,
it is a radial chamfer, meaning it doesn't not have a flat plane.. there is little or no Hot spot with a sinus chamfer. So internal stress across the total plane is equal, so when they expand and contract, they do it at the same rate, because there are no hot spots... Casted holes do the same thing... because there are differences in the stress between surface and holes...the whole rotor expands and contracts at the same rate...
Straight Drilled Hole ------------------->
A high stress and heat build up area forms at the intersection of the rotor and drilled edge.
Countersunk Hole ----------------------->
Countersinking increases the external surface area of the hole, thus reducing heat, but still contains edges prone to stress and heat build up.
Radius Hole -------------------------------->
The Radius Chamfer increases the hole cooling area thus reducing heat, but still contains sharp edges.
SP* Sinusoidal Curved and Chamfered Hole ----------------------->
Absolutely no sharp edges. The smooth design promotes cooling and minimizes stress, reducing the possibility of heat checking while increasing both rotor and pad life.
The Sinus-Curve is an example of a design inspired by mathematical principles. Although this process is well known in the industry, it is costly, but it is perfect for those wanting bling for their street car with some spirited braking...
My Eradispeed rotors have sinusoidal chamfers... Not a Baer application, I did them myself...
I hope the pictures make this clearer
Bill aka ET
when holes are drilled at 90 degrees to the fire path, the sharp 90 degree corner creates a "HOT Spot" these corners get 30% hotter than the rest of the rotor. This is cause by angular stress over variable planes. its the effect of drilling that cause the molecules to move closer together at the corners which causes this stress. When stress is relieved or equal , all the molecules are the same distance apart...
A 45 degree chamfer reduces the angular plane thus reducing the Hot spot, so internal stress is less, and this helps with cracking at the angles...no sharp corners
Better than a 45 degree champer is something called a sinus chamfer,
it is a radial chamfer, meaning it doesn't not have a flat plane.. there is little or no Hot spot with a sinus chamfer. So internal stress across the total plane is equal, so when they expand and contract, they do it at the same rate, because there are no hot spots... Casted holes do the same thing... because there are differences in the stress between surface and holes...the whole rotor expands and contracts at the same rate...
Straight Drilled Hole ------------------->
A high stress and heat build up area forms at the intersection of the rotor and drilled edge.
Countersunk Hole ----------------------->
Countersinking increases the external surface area of the hole, thus reducing heat, but still contains edges prone to stress and heat build up.
Radius Hole -------------------------------->
The Radius Chamfer increases the hole cooling area thus reducing heat, but still contains sharp edges.
SP* Sinusoidal Curved and Chamfered Hole ----------------------->
Absolutely no sharp edges. The smooth design promotes cooling and minimizes stress, reducing the possibility of heat checking while increasing both rotor and pad life.
The Sinus-Curve is an example of a design inspired by mathematical principles. Although this process is well known in the industry, it is costly, but it is perfect for those wanting bling for their street car with some spirited braking...
My Eradispeed rotors have sinusoidal chamfers... Not a Baer application, I did them myself...
I hope the pictures make this clearer
Bill aka ET
Now that my friends.........is an explanation. Today is a good day, I learned another thing.
03-12-2006, 06:58 PM
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St. Jude Donor '03-'04
BTW I have 50,000 miles on these 2 piece eradispeed rotors with sinusoidal holes.... when this picture was taken... NO CRACKS
Car now has 61,000 miles, same rotors still looking great.
Car now has 61,000 miles, same rotors still looking great.
Last edited by Evil-Twin; 04-26-2006 at 05:42 PM.
03-12-2006, 08:06 PM
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Originally Posted by azmusclecar
Now that my friends.........is an explanation. Today is a good day, I learned another thing.
Three to four hours or race use and they are shot. cracks from the holes of these cast in camfered holes in the big porsche brembo rotors or a Porsche GT3 race car.
For street use they are fine, but not for racing.
03-12-2006, 08:18 PM
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St. Jude Donor '03-'04
Originally Posted by Evil-Twin
The Sinus-Curve is an example of a design inspired by mathematical principles. Although this process is well known in the industry, it is costly, but it is perfect for those wanting bling for their street car with some spirited braking...
My Eradispeed rotors have sinusoidal chamfers... Not a Baer application, I did them myself...
My Eradispeed rotors have sinusoidal chamfers... Not a Baer application, I did them myself...
its the best type of chamfer for drilled and slotted rotors for the street..
AS mentioned above drilled and slotted rotors have no place on the track.
03-13-2006, 10:13 AM
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St. Jude Donor '03-'04
I'm not just another pretty face ya know ! 
