There are differences in disc rotors: These are typically:

• Material - Stainless steel is the most commonly used rotor, but you can get carbon and other exotic materials, and probably (although I have not seen it myself) at the other extreme, mild steel.

• Material Quailty - There is stainless and then theres stainless. As with carbion. This can affect the rust resistance and strenght of the disc

• Amount of material - thickness of disc as well as the amount in the center section (spokes)

• Design. A disc needs to be round and flat, but within these bounds, most have holes (how much, how many and what shape varies) that allow better cooling and water sheading. Theres also variatons of the outer rim that are supposed to clear mud from the caliper better. The other aspect is the discs response to vibrations and harmonics, a good design is more resistant to squealing.

So how does this all add up: Saying a disc is "just" as stamped piece of stainless and they are all the same is like saying a bicycle has 2 wheels and pedals, its correct and misleading at the same time.

There is no doubt that there is differene between the discs on a Kmart kids bike compared to a $10K Downhill racer. The question then is "how much difference". Weight is important one for many of us - but at some point the $/gram savings are not worth it. Noise is a problem that is impossible for an individual to test for and imposisble to live with squealing brakes. I don't know if price/quality makes any difference, but I do know changing to different discs can. Ability to clear mud is important to me, but not so much, if at all for others. That said, I can't be sure the shaped profiles make a difference. The cooling issue is probably mute, as I am not aware of problems with brakes overheating (except maybe in extreme compedative environs)

Unfortunately I have no idea how to tell if higher price is a "Brand tax" or a better rotor.

There are differences in disc rotors: These are typically:

• Material - Stainless steel is the most commonly used rotor, but you can get carbon and other exotic materials, and probably (although I have not seen it myself) at the other extreme, mild steel.

• Material Quality - There is stainless and then there's stainless. As with carbon. This can affect the rust resistance and strength of the disc

• Amount of material - thickness of disc as well as the amount in the center section (spokes)

• Design. A disc needs to be round and flat, but within these bounds, most have holes (how much, how many and what shape varies) that allow better cooling and water sheading. There are also variations of the outer rim that are supposed to clear mud from the caliper better. The other aspect is the discs response to vibrations and harmonics, a good design is more resistant to squealing.

So how does this all add up: saying a disc is "just" as stamped piece of stainless and they are all the same is like saying a bicycle has 2 wheels and pedals, its correct and misleading at the same time.

There is no doubt that there is difference between the discs on a K-mart kids bike compared to a $10K Downhill racer. The question then is "how much difference". Weight is important one for many of us - but at some point the $/gram savings are not worth it. Noise is a problem that is impossible for an individual to test for and impossible to live with squealing brakes. I don't know if price/quality makes any difference, but I do know changing to different discs can. Ability to clear mud is important to me, but not so much, if at all for others. That said, I can't be sure the shaped profiles make a difference. The cooling issue is probably moot, as I am not aware of problems with brakes overheating (except maybe in extreme competitive environs)

Unfortunately I have no idea how to tell if higher price is a "Brand tax" or a better rotor.

There are differences in disc rotors: These are typically

Material - Stainless steel is the most commonly used rotor, but you can get carbon and other exotic materials, and probably (although I have not seen it myself) at the other extreme, mild steel.

Material Quailty - There is stainless and then theres stainless. As with carbion. This can affect the rust resistance and strenght of the disc

Amount of material - thickness of disc as well as the amount in the center section (spokes)

Design. A disc needs to be round and flat, but within these bounds, most have holes (how much, how many and what shape varies) that allow better cooling and water sheading. Theres also variatons of the outer rim that are supposed to clear mud from the caliper better. The other aspect is the discs response to vibrations and harmonics, a good design is more resistant to squealing.

So how does this all add up: Saying a disc is "just" as stamped piece of stainless and they are all the same is like saying a bicycle has 2 wheels and pedals, its correct and misleading at the same time.

There is no doubt that there is differene between the discs on a Kmart kids bike compared to a $10K Downhill racer. The question then is "how much difference". Weight is important one for many of us - but at some point the $/gram savings are not worth it. Noise is a problem that is impossible for an individual to test for and imposisble to live with squealing brakes. I don't know if price/quality makes any difference, but I do know changing to different discs can. Ability to clear mud is important to me, but not so much, if at all for others. That said, I can't be sure the shaped profiles make a difference. The cooling issue is probably mute, as I am not aware of problems with brakes overheating (except maybe in extreme compedative environs)

Unfortunately I have no idea how to tell if higher price is a "Brand tax" or a better rotor.

There are differences in disc rotors: These are typically:

• Material - Stainless steel is the most commonly used rotor, but you can get carbon and other exotic materials, and probably (although I have not seen it myself) at the other extreme, mild steel.

• Material Quailty - There is stainless and then theres stainless. As with carbion. This can affect the rust resistance and strenght of the disc

• Amount of material - thickness of disc as well as the amount in the center section (spokes)

• Design. A disc needs to be round and flat, but within these bounds, most have holes (how much, how many and what shape varies) that allow better cooling and water sheading. Theres also variatons of the outer rim that are supposed to clear mud from the caliper better. The other aspect is the discs response to vibrations and harmonics, a good design is more resistant to squealing.

So how does this all add up: Saying a disc is "just" as stamped piece of stainless and they are all the same is like saying a bicycle has 2 wheels and pedals, its correct and misleading at the same time.

There is no doubt that there is differene between the discs on a Kmart kids bike compared to a $10K Downhill racer. The question then is "how much difference". Weight is important one for many of us - but at some point the $/gram savings are not worth it. Noise is a problem that is impossible for an individual to test for and imposisble to live with squealing brakes. I don't know if price/quality makes any difference, but I do know changing to different discs can. Ability to clear mud is important to me, but not so much, if at all for others. That said, I can't be sure the shaped profiles make a difference. The cooling issue is probably mute, as I am not aware of problems with brakes overheating (except maybe in extreme compedative environs)

Unfortunately I have no idea how to tell if higher price is a "Brand tax" or a better rotor.