Hi guys,
I was out last evening and a auto enthusiast who saw my car gave me a compliment about my car. But then he took notice of the red color brakes. He said front calipers are nice and huge but the rear calipers were tiny in comparison. I always thought this too, since getting my car. Why did Jaguar make the rear calipers so small. I think it takes away from the cars look. The carbon ceramic brake calipers are huge front and rear calipers. Why didn't they make the standard brake calipers big on rear like the ceramic brakes. Did they simply skimp out on this detail?
You thoughts please.

 

Maybe because the vast majority of the stopping power needed is in the front. When you apply the brakes, the first thing that happens is that weight transfers forward (momentum). This unloads the rear suspension - less weight on the rear. Less weight means less braking force needed.

JLR could have used larger discs and adjusted proportioning to compensate. All that would mean is that the rear might look a bit cooler but would have more unsprung weight.

As an example, on my last bike front and rear brakes were separate. (Current bike has ABS so I only need to pull the front handle.) At any rate, the only time that I used the rear was on grass or gravel or if I was stupid enough to actually need that addl. 10% stopping (only once). On a bike when you stop hard the rear really unloads and anything other than a very light touch on the rear causes lockup which can easily cause loss of control.

 

Thanks for your detailed explanation. I basically know what you described in your reply. You hit the nail on its head with this;
"JLR could have used larger discs and adjusted proportioning to compensate. All that would mean is that the rear might look a bit cooler"
From a cosmetic point of view, I think rear calipers should match in size with the front brakes.
Thanks....

 

One of the options on the F-Type is "super performance" brakes, which are the same as those on my XFR - 380 mm front and 376 mm rear - although even then the rear calipers aren't all that big and they still look a bit feeble compared to the front calipers. The rotors themselves, even though they are 376 mm in diameter, have a large central area which is "blank" and not touched by the pads. The pads are hardly any bigger than the stock 326 mm rear pads.

 

Even if the pads are virtually the same size, the swept area (per rotation) is far greater, effecting cooler braking and also applying the stopping friction on a longer moment arm for more stopping force. But as Dogbreath mentioned above, most of the braking occurs at the front (approximately 70%), so the rear brakes only need to be half as effective. Motorcycles present a good example forward weight transfer and the potential problem of too much rear braking (though ABS will prevent that issue)

 

Even if the pads are virtually the same size, the swept area (per rotation) is far greater, effecting cooler braking and also applying the stopping friction on a longer moment arm for more stopping force. But as Dogbreath mentioned above, most of the braking occurs at the front (approximately 70% under heavy braking), so the rear brakes only need to be half as effective. Motorcycles present a good example of forward weight transfer and the potential problem of too much rear braking (though ABS will prevent that issue)

 

After owning numerous performance vehicles the F type ranks last in breaking feel and power. When breaking in my other vehicles I felt confident applying the brakes in a short distance. Again my opinion.

 

Which of the 4 brake options do you have?