evosport Rotors Now In Stock
Super Member
Joined: Oct 2004
Posts: 587
Likes: 1
From: New Jersey
2005 E55 Delivered 01/07/05
Originally Posted by ricky.agrawal
How much is better handling worth to you? Especially on a product that has extensive R&D, a fantastic support team, and they look wicked tight as well?
Better Handling, Gee in all my years I never once heard of a brake rotor improving the handling of a car???? Can you please help me out and explain it to me???
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Joined: Nov 2004
Posts: 1,143
Likes: 3
From: Sydney, Australia
2017 S63 Coupe Iridium Silver
Originally Posted by MBH
Better Handling, Gee in all my years I never once heard of a brake rotor improving the handling of a car???? Can you please help me out and explain it to me???
Take a big angle grinder with a heavy cutting wheel and start it. The torque will wrench your hands and is quite difficult to change angles whilst it's spinning at several thousand RPM.
NOW, put on the thinnest, lightest cutting wheel and try it. It's much easier to hold on to and control.
The rotational energy of the heavy cast iron brake rotors compared to the lighter ceramic brakes will do the came to your acceleration innertia and steering response.
Last edited by Rafal; Sep 16, 2005 at 08:55 PM.
Super Member
Joined: Oct 2004
Posts: 603
Likes: 0
From: Bay Area, CA
2005 E55, 2010 ML350
Originally Posted by Rafal
The rotational energy of the heavy cast iron brake rotors compared to the lighter ceramic brakes will do the came to your acceleration innertia and steering response.
the lighter rotors should be easier to move for the steering system, and lower the weight of the car. but our rotors do not spin anywhere close to the speeds of an angle grinder. if they did, some of you would have no tires left. so perhaps lighter rotors plus lighter rims would give us an unsprung weight loss for the car, greater than if some of us stopped eating krispy kremes every day. Acceleration = Force / mass. Lower the mass enough, and your acceleration will increase. Simple physics.
the whole purpose of the cross drilling is heat dissipation? so you can brake harder and it is less likely that braking will degrade with heat rise as compared to OEM rotors which should retain the heat longer. only changing the brake pads themselves (making them bigger) will stop our beasts more quickly. but then again, the only time i drove hard enough to get the big red warning was at the AMG event. let me know if i'm wrong on any of these points, i'm very happy to be corrected and learn something new.
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Joined: Nov 2004
Posts: 1,143
Likes: 3
From: Sydney, Australia
2017 S63 Coupe Iridium Silver
Originally Posted by gmdebruyn
the ceramic brakes rotate? you can't compare the brakes to the rotors. the rotors spin, the brakes do not.
the lighter rotors should be easier to move for the steering system, and lower the weight of the car. but our rotors do not spin anywhere close to the speeds of an angle grinder. if they did, some of you would have no tires left. so perhaps lighter rotors plus lighter rims would give us an unsprung weight loss for the car, greater than if some of us stopped eating krispy kremes every day. Acceleration = Force / mass. Lower the mass enough, and your acceleration will increase. Simple physics.
the whole purpose of the cross drilling is heat dissipation? so you can brake harder and it is less likely that braking will degrade with heat rise as compared to OEM rotors which should retain the heat longer. only changing the brake pads themselves (making them bigger) will stop our beasts more quickly. but then again, the only time i drove hard enough to get the big red warning was at the AMG event. let me know if i'm wrong on any of these points, i'm very happy to be corrected and learn something new.
the lighter rotors should be easier to move for the steering system, and lower the weight of the car. but our rotors do not spin anywhere close to the speeds of an angle grinder. if they did, some of you would have no tires left. so perhaps lighter rotors plus lighter rims would give us an unsprung weight loss for the car, greater than if some of us stopped eating krispy kremes every day. Acceleration = Force / mass. Lower the mass enough, and your acceleration will increase. Simple physics.
the whole purpose of the cross drilling is heat dissipation? so you can brake harder and it is less likely that braking will degrade with heat rise as compared to OEM rotors which should retain the heat longer. only changing the brake pads themselves (making them bigger) will stop our beasts more quickly. but then again, the only time i drove hard enough to get the big red warning was at the AMG event. let me know if i'm wrong on any of these points, i'm very happy to be corrected and learn something new.
They are not made for weight savings or handling benefits either, but friction and temperature range improvement. Log onto EBC web site and read up their sales spiel on Red Stuff pads.My analogy was purely for the Ceramic Rotors and even if they don't spin as fast as an angle grinder, the point is made. Don't be so literal!
Super Member
Joined: Oct 2004
Posts: 603
Likes: 0
From: Bay Area, CA
2005 E55, 2010 ML350
Originally Posted by Rafal
Are we talking cross purposes here? Of course ceramic brake pads do not rotate...doh They are not made for weight savings or handling benefits either, but friction and temperature range improvement. Log onto EBC web site and read up their sales spiel on Red Stuff pads.
My analogy was purely for the Ceramic Rotors and even if they don't spin as fast as an angle grinder, the point is made. Don't be so literal!
They are not made for weight savings or handling benefits either, but friction and temperature range improvement. Log onto EBC web site and read up their sales spiel on Red Stuff pads.My analogy was purely for the Ceramic Rotors and even if they don't spin as fast as an angle grinder, the point is made. Don't be so literal!
cheers,
Gareth
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Senior Member
Joined: Jun 2005
Posts: 342
Likes: 1
2012 C63 Black Series Coupe
Originally Posted by MBH
Better Handling, Gee in all my years I never once heard of a brake rotor improving the handling of a car???? Can you please help me out and explain it to me???
Reducing unsprung mass improves handling, ride and braking, particularly on uneven surfaces. The lower the unsprung weight, the less work the shocks and springs have to do to keep the tires in contact with the road over bumpy surfaces. Note that as the wheel diameter or width increases, the weight of the overall wheel and tire package increases, thereby increasing unsprung weight. This runs counter to the current trend of mounting the largest diameter wheels one can fit to a car. Look at a race car -- they do NOT use 20" wheels. This is one factor that makes me think I'd be better off finding the best 18" wheels I can source for my E55 wagon...Here's the engineering explanation from the net:
Weight saving:
Reducing unsprung mass (Wheels, discs etc) has a far greater performance benefit than reducing sprung mass (bodywork etc). In racing, some designers use a factor of eight. For example, saving 1kg on a wheel weight gaives the same performance gain as saving 8kg of sprung weight. This is due to the following benefits :
Braking/Acceleration
The force required to start a wheel rolling (moment of inertia) increases with the mass of the wheel. The same is true of the force required to stop a wheel, and so reducing the wheels weight, improves acceleration and braking efficiency. Since less energy is required to start and stop the vehicle, fuel efficiency also improves, but is not often noticed as the driver simply goes faster!
Gyroscopic effect :
Reducing the wheel mass also reduces the gyroscopic effect of the wheel. When a wheel is spinning, it is very difficult to make it change direction, but the lower the mass of the wheel, the easier it is to flick from side to side. Try holding a front wheel at arms length via a spindle, spin it and then simulate diving in and out of a corner. The effort required is considerable, but it becomes significantly easier as the wheel mass reduces. Consequently, this has a major effect on the handling of a motorcycle.
Radius of Gyration:
This is more a function of wheel design rather than pure weight reduction, but the two are inextricably linked. The mass of a wheel is deemed to act at a certain radius from the center of the wheel (radius of gyration). In order to improve the performance of the wheel, the designer will try to reduce this radius, so that it acts as close to the wheel center as possible.
To demonstrate this, try swinging a weight on a length of string around your head. The shorter the string, the easier it is to swing. Hence reducing the radius of gyration, improves the manoeuvrability of the motorcycle. This is achieved by lightening the rim as this is on the extreme radius, and designing the spoke system with minimal weight at the extreme, whilst maintaining the required strength and stiffness.
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Joined: Nov 2004
Posts: 1,143
Likes: 3
From: Sydney, Australia
2017 S63 Coupe Iridium Silver
Originally Posted by brt3
I'm not an engineer, but I play one on television... Reducing unsprung mass improves handling, ride and braking, particularly on uneven surfaces. The lower the unsprung weight, the less work the shocks and springs have to do to keep the tires in contact with the road over bumpy surfaces. Note that as the wheel diameter or width increases, the weight of the overall wheel and tire package increases, thereby increasing unsprung weight. This runs counter to the current trend of mounting the largest diameter wheels one can fit to a car. Look at a race car -- they do NOT use 20" wheels. This is one factor that makes me think I'd be better off finding the best 18" wheels I can source for my E55 wagon...
Here's the engineering explanation from the net:
Weight saving:
Reducing unsprung mass (Wheels, discs etc) has a far greater performance benefit than reducing sprung mass (bodywork etc). In racing, some designers use a factor of eight. For example, saving 1kg on a wheel weight gaives the same performance gain as saving 8kg of sprung weight. This is due to the following benefits :
Braking/Acceleration
The force required to start a wheel rolling (moment of inertia) increases with the mass of the wheel. The same is true of the force required to stop a wheel, and so reducing the wheels weight, improves acceleration and braking efficiency. Since less energy is required to start and stop the vehicle, fuel efficiency also improves, but is not often noticed as the driver simply goes faster!
Gyroscopic effect :
Reducing the wheel mass also reduces the gyroscopic effect of the wheel. When a wheel is spinning, it is very difficult to make it change direction, but the lower the mass of the wheel, the easier it is to flick from side to side. Try holding a front wheel at arms length via a spindle, spin it and then simulate diving in and out of a corner. The effort required is considerable, but it becomes significantly easier as the wheel mass reduces. Consequently, this has a major effect on the handling of a motorcycle.
Radius of Gyration:
This is more a function of wheel design rather than pure weight reduction, but the two are inextricably linked. The mass of a wheel is deemed to act at a certain radius from the center of the wheel (radius of gyration). In order to improve the performance of the wheel, the designer will try to reduce this radius, so that it acts as close to the wheel center as possible.
To demonstrate this, try swinging a weight on a length of string around your head. The shorter the string, the easier it is to swing. Hence reducing the radius of gyration, improves the manoeuvrability of the motorcycle. This is achieved by lightening the rim as this is on the extreme radius, and designing the spoke system with minimal weight at the extreme, whilst maintaining the required strength and stiffness.
Reducing unsprung mass improves handling, ride and braking, particularly on uneven surfaces. The lower the unsprung weight, the less work the shocks and springs have to do to keep the tires in contact with the road over bumpy surfaces. Note that as the wheel diameter or width increases, the weight of the overall wheel and tire package increases, thereby increasing unsprung weight. This runs counter to the current trend of mounting the largest diameter wheels one can fit to a car. Look at a race car -- they do NOT use 20" wheels. This is one factor that makes me think I'd be better off finding the best 18" wheels I can source for my E55 wagon...Here's the engineering explanation from the net:
Weight saving:
Reducing unsprung mass (Wheels, discs etc) has a far greater performance benefit than reducing sprung mass (bodywork etc). In racing, some designers use a factor of eight. For example, saving 1kg on a wheel weight gaives the same performance gain as saving 8kg of sprung weight. This is due to the following benefits :
Braking/Acceleration
The force required to start a wheel rolling (moment of inertia) increases with the mass of the wheel. The same is true of the force required to stop a wheel, and so reducing the wheels weight, improves acceleration and braking efficiency. Since less energy is required to start and stop the vehicle, fuel efficiency also improves, but is not often noticed as the driver simply goes faster!
Gyroscopic effect :
Reducing the wheel mass also reduces the gyroscopic effect of the wheel. When a wheel is spinning, it is very difficult to make it change direction, but the lower the mass of the wheel, the easier it is to flick from side to side. Try holding a front wheel at arms length via a spindle, spin it and then simulate diving in and out of a corner. The effort required is considerable, but it becomes significantly easier as the wheel mass reduces. Consequently, this has a major effect on the handling of a motorcycle.
Radius of Gyration:
This is more a function of wheel design rather than pure weight reduction, but the two are inextricably linked. The mass of a wheel is deemed to act at a certain radius from the center of the wheel (radius of gyration). In order to improve the performance of the wheel, the designer will try to reduce this radius, so that it acts as close to the wheel center as possible.
To demonstrate this, try swinging a weight on a length of string around your head. The shorter the string, the easier it is to swing. Hence reducing the radius of gyration, improves the manoeuvrability of the motorcycle. This is achieved by lightening the rim as this is on the extreme radius, and designing the spoke system with minimal weight at the extreme, whilst maintaining the required strength and stiffness.
Senior Member
Joined: Mar 2005
Posts: 397
Likes: 0
From: Sunny S. California
03 E500
Originally Posted by brt3
I'm not an engineer, but I play one on television... Reducing unsprung mass improves handling, ride and braking, particularly on uneven surfaces. The lower the unsprung weight, the less work the shocks and springs have to do to keep the tires in contact with the road over bumpy surfaces. Note that as the wheel diameter or width increases, the weight of the overall wheel and tire package increases, thereby increasing unsprung weight. This runs counter to the current trend of mounting the largest diameter wheels one can fit to a car. Look at a race car -- they do NOT use 20" wheels. This is one factor that makes me think I'd be better off finding the best 18" wheels I can source for my E55 wagon...
Here's the engineering explanation from the net:
Weight saving:
Reducing unsprung mass (Wheels, discs etc) has a far greater performance benefit than reducing sprung mass (bodywork etc). In racing, some designers use a factor of eight. For example, saving 1kg on a wheel weight gaives the same performance gain as saving 8kg of sprung weight. This is due to the following benefits :
Braking/Acceleration
The force required to start a wheel rolling (moment of inertia) increases with the mass of the wheel. The same is true of the force required to stop a wheel, and so reducing the wheels weight, improves acceleration and braking efficiency. Since less energy is required to start and stop the vehicle, fuel efficiency also improves, but is not often noticed as the driver simply goes faster!
Gyroscopic effect :
Reducing the wheel mass also reduces the gyroscopic effect of the wheel. When a wheel is spinning, it is very difficult to make it change direction, but the lower the mass of the wheel, the easier it is to flick from side to side. Try holding a front wheel at arms length via a spindle, spin it and then simulate diving in and out of a corner. The effort required is considerable, but it becomes significantly easier as the wheel mass reduces. Consequently, this has a major effect on the handling of a motorcycle.
Radius of Gyration:
This is more a function of wheel design rather than pure weight reduction, but the two are inextricably linked. The mass of a wheel is deemed to act at a certain radius from the center of the wheel (radius of gyration). In order to improve the performance of the wheel, the designer will try to reduce this radius, so that it acts as close to the wheel center as possible.
To demonstrate this, try swinging a weight on a length of string around your head. The shorter the string, the easier it is to swing. Hence reducing the radius of gyration, improves the manoeuvrability of the motorcycle. This is achieved by lightening the rim as this is on the extreme radius, and designing the spoke system with minimal weight at the extreme, whilst maintaining the required strength and stiffness.
Reducing unsprung mass improves handling, ride and braking, particularly on uneven surfaces. The lower the unsprung weight, the less work the shocks and springs have to do to keep the tires in contact with the road over bumpy surfaces. Note that as the wheel diameter or width increases, the weight of the overall wheel and tire package increases, thereby increasing unsprung weight. This runs counter to the current trend of mounting the largest diameter wheels one can fit to a car. Look at a race car -- they do NOT use 20" wheels. This is one factor that makes me think I'd be better off finding the best 18" wheels I can source for my E55 wagon...Here's the engineering explanation from the net:
Weight saving:
Reducing unsprung mass (Wheels, discs etc) has a far greater performance benefit than reducing sprung mass (bodywork etc). In racing, some designers use a factor of eight. For example, saving 1kg on a wheel weight gaives the same performance gain as saving 8kg of sprung weight. This is due to the following benefits :
Braking/Acceleration
The force required to start a wheel rolling (moment of inertia) increases with the mass of the wheel. The same is true of the force required to stop a wheel, and so reducing the wheels weight, improves acceleration and braking efficiency. Since less energy is required to start and stop the vehicle, fuel efficiency also improves, but is not often noticed as the driver simply goes faster!
Gyroscopic effect :
Reducing the wheel mass also reduces the gyroscopic effect of the wheel. When a wheel is spinning, it is very difficult to make it change direction, but the lower the mass of the wheel, the easier it is to flick from side to side. Try holding a front wheel at arms length via a spindle, spin it and then simulate diving in and out of a corner. The effort required is considerable, but it becomes significantly easier as the wheel mass reduces. Consequently, this has a major effect on the handling of a motorcycle.
Radius of Gyration:
This is more a function of wheel design rather than pure weight reduction, but the two are inextricably linked. The mass of a wheel is deemed to act at a certain radius from the center of the wheel (radius of gyration). In order to improve the performance of the wheel, the designer will try to reduce this radius, so that it acts as close to the wheel center as possible.
To demonstrate this, try swinging a weight on a length of string around your head. The shorter the string, the easier it is to swing. Hence reducing the radius of gyration, improves the manoeuvrability of the motorcycle. This is achieved by lightening the rim as this is on the extreme radius, and designing the spoke system with minimal weight at the extreme, whilst maintaining the required strength and stiffness.
This info should be referenced in the future when some dofus makes a statement like "but my 21 inch wheel is lighter than my stock 18s so I am performance" post. 
Super Member
Joined: Aug 2005
Posts: 665
Likes: 0
C'mon guys - you can't take the rotational effects of wheels as applied to a motorcycle and say they will have the same impact on a car. It's a totally different set of dynamics. Think about this: the bike is sitting perfectly balanced on its two tires, with no external support. How hard would it be to push it over? How hard would it be to push a car onto its side? When applying forces to a moving vehicle, you have to take its linear momentum into account, which is its mass times velocity.
The mass of the tire/wheel/rotor of a bike is significant compared to the total mass of the bike. The opposite is true for a car that weighs 2+ tons. Plus, there's that balancing on two wheels thing mentioned above.
This effect gets worse when you use lighter rotors. Since the rotor is close to the center of the wheel (compared to the tire/wheel rim), removing rotor weight will reduce the mass near the center and will actually increase the Radius of Gyration.
Any handling improvement due to lighter rotors would be operator-induced. If the driver is skilled enough to interpret tire feedback when driving on a handling course, then theoretically, a lighter rotating mass could provide quicker feedback to what corrections the tires need. But, this would be more likely on a car tuned for road courses, and less likely on an E55 with its air-ride suspension.
Originally Posted by brt3
Gyroscopic effect :
Reducing the wheel mass also reduces the gyroscopic effect of the wheel. When a wheel is spinning, it is very difficult to make it change direction, but the lower the mass of the wheel, the easier it is to flick from side to side. Try holding a front wheel at arms length via a spindle, spin it and then simulate diving in and out of a corner. The effort required is considerable, but it becomes significantly easier as the wheel mass reduces. Consequently, this has a major effect on the handling of a motorcycle.
Reducing the wheel mass also reduces the gyroscopic effect of the wheel. When a wheel is spinning, it is very difficult to make it change direction, but the lower the mass of the wheel, the easier it is to flick from side to side. Try holding a front wheel at arms length via a spindle, spin it and then simulate diving in and out of a corner. The effort required is considerable, but it becomes significantly easier as the wheel mass reduces. Consequently, this has a major effect on the handling of a motorcycle.
Originally Posted by brt3
Radius of Gyration:
This is more a function of wheel design rather than pure weight reduction, but the two are inextricably linked. The mass of a wheel is deemed to act at a certain radius from the center of the wheel (radius of gyration). In order to improve the performance of the wheel, the designer will try to reduce this radius, so that it acts as close to the wheel center as possible.
This is more a function of wheel design rather than pure weight reduction, but the two are inextricably linked. The mass of a wheel is deemed to act at a certain radius from the center of the wheel (radius of gyration). In order to improve the performance of the wheel, the designer will try to reduce this radius, so that it acts as close to the wheel center as possible.
Any handling improvement due to lighter rotors would be operator-induced. If the driver is skilled enough to interpret tire feedback when driving on a handling course, then theoretically, a lighter rotating mass could provide quicker feedback to what corrections the tires need. But, this would be more likely on a car tuned for road courses, and less likely on an E55 with its air-ride suspension.
Senior Member
Joined: Jun 2005
Posts: 342
Likes: 1
2012 C63 Black Series Coupe
Originally Posted by Rafal
Thanks a lot! This is an excellent explanation, far better than my "angle grinder theory" and with more detail. Unfortunately, I am certain that you will get asked by some bright spark, what does an E55 have to do with a motorcycle...LOL?
I will say this -- I completely disagree with Grumpy, but he's welcome to his opinions. I have a good friend with a new Porsche 997/911S; we've each driven identical cars with and without the PCCB (ceramic rotors) system (which he ordered on his car). The difference in the cars is NOT subtle; the reduction in unsprung weight genuinely improves the handling and the ride (not to mention the braking). BTW, Porsche quotes an 11-pound reduction (per corner) in unsprung weight with PCCB. Since a 997 weighs around 3200 pounds (fueled and fully optioned), I have little doubt that losing 15 lbs. per corner on a E55 will also be readily noticeable.
If others disagree they should spend their money where it matters to them, whether that be 20" "bling", over-the-top exhaust systems (go vrus!), carbon-fiber hoods, or whatever floats their boat. Each of us comes to E55 ownership with different expectations. I had a 997/911S on order, but decided I liked having a fast car I could drive 75-80% of the time. So, the single biggest problem I have with the E55 is it's handling (or occasional lack thereof). I realize you can't have everything in a single car, but if I can significantly improve the handling of my Beast I'll be a (very) happy camper.
