Drums vs. discs

[crisis]

Drum brakes can put more friction material into contact with metal for braking effort than similarly sized discs can.

You can , for a price, equal this with dual calipers. I would think large discs would also be lighter than equivalently performing drums and as such offer less inertia and unsprung weight. As stated previoulsy though I think cooling is one of the main benifits. Brake fade with drums comes quick and fast.

[Blue Supra]

what is brake fade in drums? ive heard it refer to and i have a slight inkling but im not sure.

[Matra et Alpine]

You can , for a price, equal this with dual calipers. I would think large discs would also be lighter than equivalently performing drums and as such offer less inertia and unsprung weight. As stated previoulsy though I think cooling is one of the main benifits. Brake fade with drums comes quick and fast.

Problem with disks is the more force you put through them it becomes nearly impossible to stop the buggars from warping.
Hence why big heavy trucks use drums and why competition cars replace rotors on a regular basis.

[Matra et Alpine]

what is brake fade in drums? ive heard it refer to and i have a slight inkling but im not sure.

It's exactly the same as for disks.
the firction material heats up beyond it's operating range and loses it's friction properties.
As drums are a LOT harder to cool than discs this is a bigger issue with drums. ( Hence why truck drivers will ALWAYS brake using the gears and engine as much as possible )
This has become a more sever problem with the loss of asbestos as friction material as metal sintered material isn't all that clever in drums. I saw an early set of metal sintered shoes STUCK to the drums as they had overheating so much that a layer of metal was melted onto the drum interior and stuck to the metal still in the shoes. Another one of the reasons for NEVER putting on the parkign brake when doign track days ( the main one is the brake can stop working as it cools )

[KnifeEdge_2K1]

maybe this has been said b4 but drum brakes have more friction material so theoretically they have more power but again the fade is an issue as well as their tendency to flood if they're submerged in water (like a big puddle of water or something)

[Rob Mann]

there is no comparison in a race car. big disk brakes will out perform drum brakes any day. however there are some slight advantages with using drum's but theses are not big enough and do not have enough effect to warrant drum brakes in a car.

[jcp123]

i got front disc/rear drum in my car. it's enough to lock 'em up.