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Here’s a postulation that the ME has dual rear brake calipers, and since both are sized bigger than parking brakes, that GM Authority is reasoning that the ME will have dual rear brake calipers for extra stopping power. Picture below.
It appears that the upcoming mid-engine Corvette will feature extremely high-performance brakes, as the latest spy shots show a dual rear caliper brake design.
About Dual Caliper Brakes
The benefits of having two sets of calipers are fairly straight forward, and boil down to three primary advantages:
Double the pistons means greater strength to clamp down on the rotors.
Double the brake pads means twice the contact area of the pads with the rotors (known by engineers as the total swept surface area).
Twice the calipers and brakes means that the hardware has to work half as hard when stopping the car, thereby allowing them to cool off twice as fast and eliminating brake fade during instances of continuous hard braking, such as racing on a track or handling course.
No matter how you spin it, the end result is superior stopping power — and good brakes on a supercar, like the mid-engine Corvette is shaping up to be, is just as important (if not more important) as acceleration, handling and other commonly-measured attributes.
And in the case of the mid-engine Corvette, the weight distribution changes significantly when compared to prior Corvette iterations, placing more of the car’s weight toward the rear wheels. We imagine that this change, in turn, increases the importance of stopping the rear wheels.
But it’s not all marks in the positive column: more calipers and pads comes more weight and mass — the sworn enemies of performance. So it will be interesting to see how Corvette engineers may have been able to mitigate this potential downside.
Parking Brake Theory
One theory surrounding the dual rear caliper setup on the mid-engine Corvette is that the additional set of rear calipers will serve as the electric parking brake for the upcoming sports car.
Typical electric parking brakes lock a vehicle’s axle into place in some fashion, either by clamping the axle or inserting a pin that prevents it from moving. In the case of the mid-engine Corvette, a significant portion of the car’s mid-ship will be taken up by the powertrain. Though electric parking brake hardware is rather compact, a possibility does exist that the engine and transmission placement would limit the space available for a parking brake to lock the axle into place. So the circumstance may have led engineers to move the electric parking brake to the rear rotors via a dedicated set of calipers.
With that said, we do not believe that the function of the second set of braking hardware on the rear wheels is for electric parking brake, due to the calipers being way too big to be for the parking brake. However, a scenario in which the second set of calipers is used for additional stopping power while doing double-duty as parking brake clamps might be spot on.
The dual caliper rear brake design is not all too common in the industry today, even among super cars, hyper cars or other high-performance exotics. However, double calipers are used on some high-performance motorcycles as well as on rear-engine dragsters — where they are prized for their ability to resist brake fade, especially after continuous runs.
But perhaps the most prominent use of the dual rear caliper design in the automotive world is the Porsche 956 — a 1980s-era prototype-style race car built for the the FIA World Sportscar Championship. In 1983, the 956 famously completed the 20.832 km (12.93 mi) circuit of the famed Nürburgring Nordschleife in 6:11.13 while qualifying for the 1000 km Sports Car race at the hands of Stefan Bellof. The performance set an all-time record, which the car and Bellof still hold to this day.
Hmm. I'm pretty sure the secondary caliper is for the parking brake.
I don't follow the argument that it's needed for better stopping power. Presumably one large caliper is cheaper/lighter than two small ones? And increasing brake rotor size is a better option for increased cooling, not more calipers. Clamping force is never the problem with braking, it's either heat in the rotor or lack of grip in the tire.
Do you never look at other cars? One of my cars has a caliper in the rear and a parking brake in the rear same as this setup.... many cars do have this arrangement it is not new or special.
Furthermore about 60-70% of braking is done by the front... there is no need to have more braking in the rear on ANY car.
Do you never look at other cars? One of my cars has a caliper in the rear and a parking brake in the rear same as this setup.... many cars do have this arrangement it is not new or special.
Furthermore about 60-70% of braking is done by the front... there is no need to have more braking in the rear on ANY car.
Hmm. I'm pretty sure the secondary caliper is for the parking brake.
I don't follow the argument that it's needed for better stopping power. Presumably one large caliper is cheaper/lighter than two small ones? And increasing brake rotor size is a better option for increased cooling, not more calipers. Clamping force is never the problem with braking, it's either heat in the rotor or lack of grip in the tire.
the “writer” knows about nothing it seems. Referencing race cars from years ago.
Like you said about heat. I have explained to many people that as long as your car can lock the brakes it has plenty of stopping power and bigger brakes only help for repeated stops.
Also the writers statement is just plain dumb.... look at the parking brake and it doesn’t even contact 100% of the rotor, not an issue at all for a parking brake.
Who would design a dual caliper setup but only Clamp part of the rotor? That would make for weird rotor wear and weird heating.
The writer does not deserve to be an automotive writer!!!!
Last edited by Steve Garrett; 05-25-2018 at 03:14 PM.
Reason: Merge Posts
Inboard rotors are sexy and reduce unsprung weight but they can really complicate rotor replacement.
It will be interesting to see how this shakes out. Two calipers adds complexity, weight and cost, things that manufacturers try to avoid. There would need to be some sort of payoff for them to add the second caliper.
Most electric parking brakes use drum brake technology with the “hat” of the rear brake rotors acting as the drum.
Even with a mid engine rearward weight bias it’s hard to imagine needing two calipers to get the job done.
Just spit-balling, but any chance the second caliper is for some sort of dedicated traction/stability control system so as to avoid over heating the primary braking system?
Just spit-balling, but any chance the second caliper is for some sort of dedicated traction/stability control system so as to avoid over heating the primary braking system?
No they would not do this. It would add a whole ofther level of complication. The ABS, stability control and traction control use one module. If they had a separate caliper for just this function you would have to add another brake line and have more channels on the controller, instead of 4 you would need 6 or 8.
No they would not do this. It would add a whole ofther level of complication. The ABS, stability control and traction control use one module. If they had a separate caliper for just this function you would have to add another brake line and have more channels on the controller, instead of 4 you would need 6 or 8.
I agree with everything you say. I’m just winging it with some what-if out of the box thinking. Remember GM was the company that brought you the original Pontiac Tempest with a bendable drive shaft, these people are capable of some strange stuff!
I agree with everything you say. I’m just winging it with some what-if out of the box thinking. Remember GM was the company that brought you the original Pontiac Tempest with a bendable drive shaft, these people are capable of some strange stuff!
I understand but this is simply a parking brake. I am not sure why some are making a big deal about it, my car and many other cars have the exact same setup.
It's pretty obviously a parking brake caliper, right? How is this even a discussion?
The author says it is "way too big" to be a parking brake, but it doesn't look oversized for that function at all if you do an image search and compare it to existing cars with a second parking brake caliper.
Finally, there is no way GM would add a second caliper for performance reasons while keeping a very small, single-piece rotor. If they wanted to increase braking performance, they'd focus on the rotor first, rather than adding more calipers.
Author is smoking something, IMO.
-T
Last edited by Trackaholic; 05-25-2018 at 04:14 PM.
If there's anything I've learned reading this section is that the vast majority of people here don't have a clue about mid-engine cars, or what other manufacturers are doing these days.
Last edited by theanswriz42; 05-25-2018 at 04:32 PM.
the “writer” knows about nothing it seems. Referencing race cars from years ago.
Yes the writer is completely clueless.....
Like you said about heat. I have explained to many people that as long as your car can lock the brakes it has plenty of stopping power and bigger brakes only help for repeated stops.
Bigger brakes are there to deal with heat--yes I am agreeing with you.
05-25-2018, 01:48 PM
ME To Have Dual Rear Brake Calipers
the “writer” knows about nothing it seems. Referencing race cars from years ago. 
