Supercar rear brakes x 2?

I think it is because that it is assumed that super car brakes will become hotter for longer than a normal car and so the handbrake is seperated to prevent "hotspotting" when the car is stationary parked. Obviously the cost of the extra caliper is pretty much of no consequence given the usual cost of the cars in question.
 
Firestar_3x said:
No, it's cause the main pads could be roasting hot and the handbrake pads won't thus they won't slip off and let the car roll down a hill nor will they warp the disk.
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Correct, and also means they can use standard calipers on the rear, without having to develop a special version with a handbrake mechanism built in.

In addition, you cant incorporate a drum into lightweight two piece bell and rotor discs either.

Those R8 calipers dont look particularly big to me.. I guess the fronts must be larger.
 
~~#M-Bizzle#~~ said:
Correct, and also means they can use standard calipers on the rear, without having to develop a special version with a handbrake mechanism built in.

In addition, you cant incorporate a drum into lightweight two piece bell and rotor discs either..
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I was talking to someone about this the other day. Like you said you can't do the drum trick and you can't build it into a 4 pot caliper you would on a sliding caliper.
 
Some cars in D1 have used similar setups.
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One for the regular footbrake, other for the hydro handbrake, saves the hydro from interfering with the footbrake circuit.
 
I ran twin (matching) calipers on my Dolomite Sprint - it had a mirrored front upright with caliper mounts on both sides, so you could just bolt up another caliper, although you did have to make up some hangers for pipework etc - so you can find instances where a car has a pair of foot braking calipers on the same wheel.
 
Firestar_3x said:
No, it's cause the main pads could be roasting hot and the handbrake pads won't thus they won't slip off and let the car roll down a hill nor will they warp the disk.
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I don't know, I'd say his assessment *is* the main reason for the handbrake caliper. Otherwise every other performance car would use it. I'd like to say it's because of floating discs, but the GT-R has a drum handbrake assembly, as do 911's, Ferrari's etc.

I guess that leaves cost of off-the-shelf Brembos vs another manufacturer caliper with a mechanical actuation or something to do with unsprung weight of extra caliper vs conventional drum assembly.
 
Fett said:
I don't know, I'd say his assessment *is* the main reason for the handbrake caliper. Otherwise every other performance car would use it. I'd like to say it's because of floating discs, but the GT-R has a drum handbrake assembly, as do 911's, Ferrari's etc.

I guess that leaves cost of off-the-shelf Brembos vs another manufacturer caliper with a mechanical actuation or something to do with unsprung weight of extra caliper vs conventional drum assembly.
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Original quote below; i only know of a handfull of cars which have rear handbrake shoes in addition to the caliper, i know of many many more cars which simply use a single caliper for both. So yes part of my original point / post was no most cars don't use rear handbrake shoes in addition to a caliper.

ScoobyDoo69 said:
I suppose that's because most cars incorporate a drum into their rear discs where as these don't?
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Firestar_3x said:
Original quote below; i only know of a handfull of cars which have rear handbrake shoes in addition to the caliper, i know of many many more cars which simply use a single caliper for both. So yes part of my original point / post was no most cars don't use rear handbrake shoes in addition to a caliper.
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I don't disbelieve you but I must have a predisposition towards drum-in-hat cars. Of then last 15 cars I've driven and including a rough roundup of family and friends cars, 25 out of 36 have shoes with calipers. Range Rover, Scoobs, Evos, BMWs, Mercs, Nissan, Porsche, Volvo and Ferrari.

Irregardless, I'm intrigued. The heat issue makes sense in isolation, but if you look at something like an RS4, or an Exige or any other "performance" car that uses a caliper with an intergrated handbrake, surely they shouldn't have that setup?

Wilwood make fast road and track calipers with the handbrake, but Brembo don't, instead offering the spot caliper. I don't know what the weight of the drum and shoes would be, so can't compare it to the 2kg Brembo.

It's nothing to do with 2 piece / floating rotors as other cars have this with shoes.

So, if somebody knows...in a caliper with an intergrated handbrake, the piston that is used for the handbrake must be seperate from the main hydraulic system. I'm assuming, please correct me if I'm wrong. Also, what "performance" cars have an intergrated parking brake that have over 2 primary pistons?

Perhaps it's because a conventional 2 piston (or 4 or 6 etc) caliper will take up the same space (and weight) as the intergrated caliper, but offer the obvious braking benefits of having two pistons for service braking in comparison to one? Maybe that's why the extra handbrake caliper is usually seen on a performance car...wasting pots in the primary caliper is unacceptable due to braking demand.

Miles off?

edit: The answer would be to build a 10-pot rear caliper with an intergrated handbrake, so cost must factor into this.
 
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