Can someone explain brake performance ?
Discussion
This may seem a bit of a novice post but can someone clear up some thoughts that have come to mind since a recent track day I attended.
It's about how brakes are affected during and after use/wear.
There are three scenarios I would like to clear up in my head, related to road car (steel with traditional pads and/or carbon ceramic with matching pads)
1. During use, the brakes get hotter and are then in their performance zone (coefficient of friction is at it's greatest) - how does overheating the brakes affect their current performance ? Is this referred to as brake fade ?
2. After use does this heat/overheat cycle affect the longevity and subsequent use of the brakes and for how long ?
3. Does prolonged wear of the pads (and disks to a lesser extent) extend the required brake pedal travel ? Or is this a misnomer and is the wear taken up by the brake system or is it insignificant ?
I know these are generic examples but any real world experience would be appreciated.
It's about how brakes are affected during and after use/wear.
There are three scenarios I would like to clear up in my head, related to road car (steel with traditional pads and/or carbon ceramic with matching pads)
1. During use, the brakes get hotter and are then in their performance zone (coefficient of friction is at it's greatest) - how does overheating the brakes affect their current performance ? Is this referred to as brake fade ?
2. After use does this heat/overheat cycle affect the longevity and subsequent use of the brakes and for how long ?
3. Does prolonged wear of the pads (and disks to a lesser extent) extend the required brake pedal travel ? Or is this a misnomer and is the wear taken up by the brake system or is it insignificant ?
I know these are generic examples but any real world experience would be appreciated.
dtmpower said:
This may seem a bit of a novice post but can someone clear up some thoughts that have come to mind since a recent track day I attended.
It's about how brakes are affected during and after use/wear.
There are three scenarios I would like to clear up in my head, related to road car (steel with traditional pads and/or carbon ceramic with matching pads)
1. During use, the brakes get hotter and are then in their performance zone (coefficient of friction is at it's greatest) - how does overheating the brakes affect their current performance ? Is this referred to as brake fade ?
2. After use does this heat/overheat cycle affect the longevity and subsequent use of the brakes and for how long ?
3. Does prolonged wear of the pads (and disks to a lesser extent) extend the required brake pedal travel ? Or is this a misnomer and is the wear taken up by the brake system or is it insignificant ?
I know these are generic examples but any real world experience would be appreciated.
As I understand it:It's about how brakes are affected during and after use/wear.
There are three scenarios I would like to clear up in my head, related to road car (steel with traditional pads and/or carbon ceramic with matching pads)
1. During use, the brakes get hotter and are then in their performance zone (coefficient of friction is at it's greatest) - how does overheating the brakes affect their current performance ? Is this referred to as brake fade ?
2. After use does this heat/overheat cycle affect the longevity and subsequent use of the brakes and for how long ?
3. Does prolonged wear of the pads (and disks to a lesser extent) extend the required brake pedal travel ? Or is this a misnomer and is the wear taken up by the brake system or is it insignificant ?
I know these are generic examples but any real world experience would be appreciated.
1. There are two things that happen during heavy use of the brakes - firstly the pads can "glaze" (i.e. get "cooked" such that their friction becomes less) and secondly the brake fluid can boil, introducing air bubbles into it and thus decreasing the effectiveness of the system.
2. If the fluid gets air in it, it needs bleeding / changing. Not sure about glazing.
3. I've never noticed pedal travel changing. There isn't a spring that makes the pads return into the calliper when the pedal is released, so the pads always sit the same distance from the disks and the fluid reservoir takes up the slack in the system.
Someone more technical will be along in a minute...
dtmpower said:
This may seem a bit of a novice post but can someone clear up some thoughts that have come to mind since a recent track day I attended.
It's about how brakes are affected during and after use/wear.
There are three scenarios I would like to clear up in my head, related to road car (steel with traditional pads and/or carbon ceramic with matching pads)
1. During use, the brakes get hotter and are then in their performance zone (coefficient of friction is at it's greatest) - how does overheating the brakes affect their current performance ? Is this referred to as brake fade ?
2. After use does this heat/overheat cycle affect the longevity and subsequent use of the brakes and for how long ?
3. Does prolonged wear of the pads (and disks to a lesser extent) extend the required brake pedal travel ? Or is this a misnomer and is the wear taken up by the brake system or is it insignificant ?
I know these are generic examples but any real world experience would be appreciated.
1) When the pads get too hot a film of gas forms between the disc and the pad, the peddle goes hard and you get less braking. If your brake fluid is old, the fluid boils first, the peddle goes soft, you get less braking (after the peddle has hit the floor)It's about how brakes are affected during and after use/wear.
There are three scenarios I would like to clear up in my head, related to road car (steel with traditional pads and/or carbon ceramic with matching pads)
1. During use, the brakes get hotter and are then in their performance zone (coefficient of friction is at it's greatest) - how does overheating the brakes affect their current performance ? Is this referred to as brake fade ?
2. After use does this heat/overheat cycle affect the longevity and subsequent use of the brakes and for how long ?
3. Does prolonged wear of the pads (and disks to a lesser extent) extend the required brake pedal travel ? Or is this a misnomer and is the wear taken up by the brake system or is it insignificant ?
I know these are generic examples but any real world experience would be appreciated.
2) Yes but it depends on the severity of the heating. I've seen pads crumble away after a stuck caliper episode.
3) Pad, disc, shoe, drum wear is taken up by the system. Increased brake pedal travel is normally air in the fluid or a fault in the system.
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