black diamond brake disc users
Discussion
appledell said:
I have a 2003 S Type which needs new brakes. Anyone using Black diamond? and what is the feedback - good bad average?
Thanks
Hi,
I've been using BD Combi disks on my RX-7 for the last year and they're absolutely excellent stoppers (using them with Hawk HT-10 pads which are basically a race pad).
Unfortunately they're not up to huge amounts of heavy stopping - mine cracked very nastily @ the last VMax (pics in Jap Chat under thread 'VMax wear'). BD are replacing them FoC but I'm going with the grooved (as opposed to grooved and drilled) discs.
The pad/disc combo is quite important though to maintain sufficient balance between front and rear.
Iain
edc said:
They can't be that good if they 'cracked very nastily'.
That's one of the 2 large cracks, plenty of smaller ones too.
DS's response was pretty good - it's a known issue under a couple of circumstances 1) Protracted breaking from high speed/dragging break peddle; 2) V.hot breaks then going through a puddle.
Not sure how their non-drilled ones would cope - would they warp or not??? Guess I'll find out if I get to go on another VMax. They coped fine with a track day at Silverstone in similarly hot temps though.
note to self, never buy drilled discs. 
nords said:
Bike discs are also drilled; is it that bike discs are inherently more cooled than car discs or because the bike is lighter which means they get away with it?
Just put drilled discs all round on my Pug!!!!
Even with big stops from high-speed you'll never put as much energy/heat into a bike disk although they're generally (from the little I've noticed on them) thinner than equivalent car breaks...
Unless you're really, really hammering the pug then you shouldn't get a problem. It too a number of big decellerations (from ~150 to ~50) followed by some track action to kill them...
I won't be using drilled disks again and will be upgrading to a larger diameter disk (and callipers to match) next year. More metal = better coping with heat in general...
Redarress said:
Ok silly question but what are the drilled holes trying to achieve ? is it to reduce the unsprung weight ? I can't really see that the holes would dissipate the heat any quicker than solid ?
When the pads heat up they produce gases which form a gas bearing lifting the pads away from the disc causing brake fade. The holes/grooves/dimples on a car are intended to disperse the gas.On a bike they may serve other functions such as dispersing water.
Just like to flesh out what PhillipM says about bike disks... "bike disks are generally made from rolled steel/stainless steel plate, not from cast iron" and this is true.... but in fact there are several materials bikers can get their disks in including ductile iron or stainless steel. Ductile iron is an iron/carbon/silicon alloy and is actually a more flexible material than plain old cast iron and dissipates heat very efficiently. They are far less prone to warping because of this.... and about 10 times more expensive!
DI disks are cut and machined then ground to make them spot-on-flat.
Race bikes tend to use ductile iron whereas standard fare is usually stainless steel. Stainless is cheaper and dissipates heat less efficiently than ductile iron. Stainless is more susceptible to fatigue.
Original equipment disks are usually low grade stainless. (that's why the disks will still rust if you don't ride it and leave it in the rain for a while.) They are usually stamped out of a 10 foot metal coil and are shaped using presses or cut by laser. Quality varies depending on what part of the original lump of hot steel coil after it is unwrapped during the manufacturing process.
All of this is very nearly interesting!
I know this because I read it in Performance Bikes. And now you know it coz I told you.
DI disks are cut and machined then ground to make them spot-on-flat.
Race bikes tend to use ductile iron whereas standard fare is usually stainless steel. Stainless is cheaper and dissipates heat less efficiently than ductile iron. Stainless is more susceptible to fatigue.
Original equipment disks are usually low grade stainless. (that's why the disks will still rust if you don't ride it and leave it in the rain for a while.) They are usually stamped out of a 10 foot metal coil and are shaped using presses or cut by laser. Quality varies depending on what part of the original lump of hot steel coil after it is unwrapped during the manufacturing process.
All of this is very nearly interesting!
I know this because I read it in Performance Bikes. And now you know it coz I told you.
Gassing Station | Suspension, Brakes & Tyres | Top of Page | What's New | My Stuff