New spy shots show that the upcoming mid-engine Corvette features some peculiar braking hardware on the rear wheels, making us wonder about their function.
Dual Caliper Brakes
One theory surrounding the second set of rear brake calipers on the mid-engine Corvette is that the second caliper will enable higher-performance braking.
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, such as the mid-engine Corvette is shaping up to be, are just as important (if not more important) as the car’s acceleration, suspension and other commonly-measured attributes.
In the case of the mid-engine Corvette, the weight distribution will likely change 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 having greater stopping power for the rear tires when compared to the fronts.
But a dual-caliper design is not all marks in the positive column: with more calipers and pads comes greater weight and mass – the sworn enemies of performance. So it will be interesting to see how Corvette engineers mitigate this potential downside… if the second set of rear calipers will, in fact, end up being for stopping duty.
Parking Brake Theory
Another theory surrounding the dual rear caliper setup on the mid-engine Corvette is that the second set of rear calipers will be responsible for the the electric parking brake for the upcoming sports car.
Typically, 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, the second set of calipers on the rear wheels seem way too big to be for the parking brake. So 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 more likely.
Mid-engine Corvette prototype features dual-caliper rear brakes
Mid-engine Corvette prototype features single-caliper front brakes
Industry-Wide Uses Of Dual Caliper Brake Designs
The dual caliper rear brake design is not common 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 (post-humorously) still hold to this day.
Porsche 956
Coincidentally, Porsche also used the 956 to test its world-famous Doppelkupplungsgetriebe (PDK) dual-clutch transmission before putting it into production in 2009.
So, what do you make of the dual calipers on mid-engine Corvette prototype? Talk to us in the comments.
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Comments
This analysis couldn’t be more wrong. That second caliper is a parking brake, replacing the usual integral drum parking brake design. And those are multi-piston front brakes too.
Did they edit the story to include the section on parking brake?
No Andrew… that section has been there from the very beginning. It’s just much more likely that Jeff didn’t actually read the piece in question…
I read the piece in question, and I’m an engineer. It’s a parking brake… no doubt, no drama, no trying to make hype of something. There are several engineering reasons to design a parking brake like this, and several other manufacturers do this too. It’s entirely conventional.
Lets cut the silliness and just admit Alex that too much has been made of this mistake. Let’s keep up the analysis as better spy pics come in, but consult an engineer. The new Corvette isn’t magic, it isn’t a UFO, most of it (and this) it is very conventional engineering science in the end. What we need to focus on is the retread engine, the new engines, the transmission, cooling – what makes this unique over other mid-engine designs. A very conventional parking brake does not make this unique in any way.
Honestly Jeff, I expected a much better explanation about the e-brake setup in question from a know-it-all “engineer”.
Assuming your theory about the second set of calipers being for e-brake duty is correct, I would have expected you to discuss the reasoning for this kind of configuration compared to that used by the C7 and compared to that used by ALL current GM vehicles. I would have also expected you to discuss the impact on weight from a second set of calipers for e-brake duty compared to the way the C7 handles the e-brake function.
Instead, here’s the chain of events that has brought us to having THIS particular, non-productive conversation:
1. Jeff reads the article, which clearly outlines two theories for the second set of rear calipers on the developmental prototype.
2. Jeff believes, through his vast amounts of “engineering” expertise that the second set of rear calipers is for e-braking duty.
3. Jeff feels the need to fly down into the comments and start flamboyantly labeling the article he just read as “factually wrong”, even though the article clearly states the theory he believes to be the case (in item #2).
If you really did read the piece in question, then why did you feel the need to start the “drama” that you yourself seem to dislike so much? Instead, it seems that you didn’t really read the article, which CLEARLY MENTIONS THE POSSIBILITY OF THE SECOND SET OF CALIPERS BEING FOR E-BRAKE DUTY, and started typing your drama-filled ostentatious comments after only reading the title. Sound about right?
Better still is that you could have made all of this much more pleasant and saved yourself (and everyone else) the drama by stating the following:
“Hey guys, the second set of calipers is for the parking brake. I’m an engineer and here are the reasons it’s changing from the current configuration.”
That would have been much more productive, pleasant and free of drama. Instead, you started a crusade, labeling the article as “misinformation” and whatever else. That’s not the way to do things, especially for someone who is a professional “engineer”, and I am calling you out on it.
Outside of all that, I feel like I should inform you that no one here at GM Authority has any issues with “being wrong” when it comes to writing about future product about which very little is known. In this case, our job is to shed light on something peculiar and to present the options and possibilities associated with that peculiar item, feature, function, etc.
And that, dear Jeff, is exactly what we have done here – and the world is a more informed place because of it, as we were the first to cover it while presenting both possibilities. Now, Corvette enthusiasts the world over will be cognizant of the existence of the second set of rear calipers on the mid-engine Corvette, and will understand that there are two possibilities for their use.
I agree with this, most likely a parking brake. It might even save weight (and MOI) compared to traditional drum in hat style parking brakes.
Jeff
We point out the possibility of the second set of calipers being a parking brake… did you miss that part?
Either way, we’ll see about who is wrong and who is right in several months’ time.
Its the parking brake… The pad doesn’t contact the entire rotor surface which would wear the rotor unevenly and decrease the performance of the main braking caliper.
Other manufactures, MB comes to mind, have used/tested a two caliper design in the FRONT where majority of the braking is done with little to no advantages.
I knew there was something off about those wheels!
Thats badass regardless. I’ve never seen a car with two brakes on one disc before
Duels rear calipers are very common in mid and rear engine applications in racing.
They add brake torque, they are much more efficient thermally and they can in some cases put more brake in a smaller wheel than one big caliper that will not fit.
I suspect this one is not an Emergency brake as the E brake needs not to be this large. It only has to hold the car in a stopped position so they are generally very small if they chose to go that route. With weight being a factor the E brake would be as small as possible.
Cars that use duels are often mid and rear engine road race cars and rear engine dragsters. Some Turbo drag racers use them for more clamping force too when building boost.
The Vette guys of late have put a lot of focus on the brakes. Just look at the ZR1 where they now use different pad material on each pad on each piston on the front calipers. They have gone to a mix of trax and street material to better work with the car.
I suspect GM here has used two smaller calipers to better deal with the cooling and to better work with the rear mass of the car.
Not sure there is much weight difference here vs. having one larger six piston caliper here. I sure there is a little mass but the end result is the improvement in braking will more than make up for it per lap.
The real questions here should be is this the standard car or is this a Z06 set up?
As for Stefan Bellof he posthumously still holds the record. The Duel 956 rear brakes were not enough at Spa. Sad day in racing.
Here is an good example of how small most E brakes are in racing and performance applications. Note this is one of the larger ones as most E brakes calipers are very small.
https://www.speedwaymotors.com/Wilwood-140-14224-Forged-Dynalite-MC4-Rear-Parking-Brake-Black,293835.html?sku=83514014224&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=EAIaIQobChMI6bng-fig2wIVwzaBCh29lQKbEAQYByABEgIkW_D_BwE
I feel like GM Authority is losing its way. Release a story with a clickbait title which leads you to think they have real info, then once you get into the story they really dont know. This is bad reporting if you ask me. Titles are miss leading and lack actual facts.
To be fair new Corvette news always draws a lot of attention and most media outlets milk it for all they can.
In this case they have news no one else has reported. While they have posted repeated news before on the Vette this is the first to point out duel rear calipers.
While I may agree with you on some of the posted stories this one is a good find. We may not know why till the press releases but we now know it has duel rear calipers.
With the Vette it is one of the most speculated car ever and while 80% what we read is wrong the photos here show what it does have.
Your post would best fit the targa post from the other day.
Milking the C8 news is one thing… but factually wrong news is another. This “analysis” of the prototype is so technically wrong that it’s ridiculous.
It is called speculation. And they all are guilty of it as the Vette program goes dark on details.
Case in point here. No one here can say exactly what is going on on the two calipers.
Some say parking brake other not. Since not look to be similar sized we just have to make our pick.
Alex can contend that I too have been critical in past stories on the obvious but here we do see two calipers and no one else has published this.
The notes here on duel calipers are plausible in different situations but till GM talks we will not know what they are thinking.
“Speculation” is a ridiculous excuse when it’s so obvious what this is. Many other cars do this the exact same way… and the upcoming GT500 uses the same parking brake system.
I’d hesitate to call this article misinformation when it’s so clear what this is. Instead, the term “engineering ignorant” fits.
Jeff – your inflammatory comments make it apparent that you are hell-bent on proving some kind of a personal agenda.
The article clearly outlines the two possibilities (actual braking vs. parking brake), and presents them as speculation, rather than fact. What part of that is difficult for you to understand?
More importantly, if you are so advanced in automotive engineering and are so well-informed about the feature(s) in question, then why didn’t you present your knowledge in the comments and elucidate the “engineering ignorant”? Instead, all you are doing is yelling “YOU’RE WRONG, YOU’RE WRONG, YOU’RE IGNORANT, BLABLABLABLA” .
In other words, your comments serve no benefit to anyone, except to unnecessary stir the pot to make yourself feel better and/or superior.
Meanwhile, this article from the “engineering ignorant” has brought to light a unique potential feature to thousands of people, most of whom found it interesting and useful. And that, dear Jeff, is more than I (or anyone else, for that matter) can say about your inflammatory yet useless comments.
And if you want to talk about the GT500, then you should note that the second set of rear calipers on that vehicle is much smaller than the second set of calipers on the mid-engine Corvette, which is reason enough to question their purpose on the latter.
Put on them bifocals and have a look for yourself:
http://fordauthority.com/2018/04/spy-pictures-2020-ford-mustang-shelby-gt500-caught-with-less-camo/
And now who is “insulting”?
They are both the same type of parking brake design, but obviously two different sizes for two very different cars with very different weights and weight balance.
Alex, time to move on and change the subject. Accept it as wrong and move on.
Jeff – you are, once again, missing the forest for the tress:
1. Looks like you took my advice and posted above an explanation for the reasoning for why you believe it’s a parking brake… but your explanation and reasoning is mediocre at best, and I would characterize it as being very subpar, especially for an esteemed “engineer”.
I truly expected so much more from someone like yourself, who has a loud mouth and a penchant to criticize others… but here we are, with an amateur explanation for your reasoning. In fact, your explanation makes me wonder if they let you work on real projects in your line of work as an “engineer”, or are you using the red Swingline stapler in the basement stapling together TPS reports?
2. As for your suggestion of “moving on”, I would appreciate the opportunity to decide when it’s time to “move on” and when it’s not. You telling me that it’s time to “move on” seems like a half-witted attempt to shut me up – when doing so is actually not necessary, since I am not defending the argument to begin with.
Instead, I’m pointing out that your delivery in the comments is sophomoric and leaves a lot to be desired. That’s it.
As the proverb goes, if you can’t take the heat stay out of the kitchen. In this case, you can’t take the heat started by your own fire… when no such fire was even necessary to begin with.
3. “And now who is “insulting”?
Not sure what you’re referring to… no one ever mentioned the word insult… nor did I insult you. What I did do is point out that your delivery of your comments straight up sucks, and that the original article mentions the possibility that you are arguing for – specifically, the possibility of the second caliper being for parking braking duty. Does that somehow insult you?
The significant disparity in the sizes of the two different calipers strongly suggests they perform two different functions – i.e. one is the e-parking brake, the other is the “brake.”
Batmobile has dual calipers!
Also, wouldn’t this just increase likelihood that your eyeballs would end up on the windshield?
Could this be a clue to the potential engine output of the engine output of the C8 Corvette especially as it has been disclosed that INDY cars will feature a 900 horsepower engine; it would be interesting if the C8 Corvette featured a twin-turbo V8 making 900 hp and reason for the dual rear-wheel calipers.