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Just got my AP Racing CP9668 front calipers installed on my GTS. Works with OEM Iron rotors but I have the Girodisc replacements since they have directional vanes unlike the OEM rotors.
These calipers have stainless steel pistons and allow for a thick 25mm pad for better thermal performance and pad life. The common pad size give me much more options for both street and pad compounds. These calipers are also 3.7lbs lighter per side than the OEM Brembos. 1.3lbs per side saved with the rotors vs the OEM Irons.
No, it's not about improving the feel. The purpose is for braking reliability and cooling. The cooling ducts have done most of the work. The best part about these calipers are the pad options and how easy it is to swap the pads. Another side benefit is that they're lighter.
No, it's not about improving the feel. The purpose is for braking reliability and cooling. The cooling ducts have done most of the work. The best part about these calipers are the pad options and how easy it is to swap the pads. Another side benefit is that they're lighter.
So how much have you spent on the ducts and brakes so far ?
Girodisc has off the shelf fitment for the GTS. The AP racing J hook rotors are not quite the OEM size. I installed the Girodisc rotors first, I didn't like the AP racing rotors because of the need to use a spacer.
So tell me can you feel an improvement in handling now that you've spent all that time and money on your brake replacement setup...?
Originally Posted by ronac
No, it's not about improving the feel. The purpose is for braking reliability and cooling. The cooling ducts have done most of the work. The best part about these calipers are the pad options and how easy it is to swap the pads. Another side benefit is that they're lighter.
1: congrats on the AP Racing Radi-cal calipers, Ronan. Just fantastic kit and is far superior to essentially anything sold as OEM on any vehicle.
2: to anyone who thinks that the OEM setup even with upgraded pads and fluid will come close to performing as well as the AP Racing BBK, well you’re wrong. These are designed to stop lap after lap consistently without any form of fade, or pedal softening. Plus the pads designed to be used with most of these calipers can be up to 1” thickness, hence last a very long time, and changing pads is dead simple. I asked Jeff Ritter who is one of the brake gurus at AP Racing here in the States if they had a fitment for the GTR, as I would have replaced my CCMs with them immediately after purchase.
3: if/when you trade the car you’ll probably get at least 66% of your purchase price back, so a great investment’!
Hello Ronac,
You've got a great braking system.
I want to install AP Racing calipers too, but I have a problem with the fixing because the centre distance is smaller than the original calipers.
How did you solve the problem, if you didn't use a spacer caliper?
I have an amg gtr with the ceramic system.
Thanks
Custom brackets were designed and machined to fit the caliper to the existing mounting points. The uprights between all the GT models are the same.
Thank you for your information, Would you have a reference to give me so that I can buy these parts. Because in France it's complicated to have information for Mercedes, it's easier with a Porsche. If you have pictures of the assembly of the caliper on the hub I'm interested.
It looks to me that there is about a 20% reduction in pad contact surface area with the AP pad / caliper setup vs OEM
More contact surface area is the idea behind big brake setups not less but
As usual, thanks for the contributions to the forum. No one called this a big brake kit. The AP caliper is a better caliper than the stock Brembos. They feature stainless scalloped pistons, and they're significantly lighter with better cooling. It's a more track oriented caliper which don't use dust boots that can easily get damaged from the heat from tracking. Probably not an issue for canyon runs. Also, the caliper uses a more common pad shape so there's more compound selection than the OEM setup.
As usual, thanks for the contributions to the forum. No one called this a big brake kit. The AP caliper is a better caliper than the stock Brembos. They feature stainless scalloped pistons, and they're significantly lighter with better cooling. It's a more track oriented caliper which don't use dust boots that can easily get damaged from the heat from tracking. Probably not an issue for canyon runs. Also, the caliper uses a more common pad shape so there's more compound selection than the OEM setup.
I'm sure the Brembo people will say the same about the AP setup and of course they will run cooler with less contact area creating less heat.
Please if you can do a 60-0 and 120-60 side by side brake test with a stock GTS so that we can see the difference in braking performance.
I'm sure the Brembo people will say the same about the AP setup and of course they will run cooler with less contact area creating less heat.
Please if you can do a 60-0 and 120-60 side by side brake test with a stock GTS so that we can see the difference in braking performance.
The advantages of the AP Racing Radi-cal brakes do not show up in a single stop; that is down to tyre performance anyway. Where the true advantage of the AP Racing equipment is found is on a road course, or when coming down long mountain roads for instance. These brakes simply will not fade, unlike the OEM brakes. You will have a consist brake pedal, and brake torque regardless of how many laps you’re doing on a road course. Besides better performance and on a road course that means being able to rely on your brakes lap after lap, the pads are much thicker leading to far greater pad life. Also, you won’t have to worry about overheating and ruining piston ‘boots’, as they aren’t used.
There is a reason why AP Racing brakes on used on multiple series of race cars, and that’s because they are one of the best brake products made, and are multiples better than the OEM brakes found on our cars. Worth every penny if you track the car; not so much if you’re just hooning around canyons perhaps.
The advantages of the AP Racing Radi-cal brakes do not show up in a single stop; that is down to tyre performance anyway. Where the true advantage of the AP Racing equipment is found is on a road course, or when coming down long mountain roads for instance. These brakes simply will not fade, unlike the OEM brakes. You will have a consist brake pedal, and brake torque regardless of how many laps you’re doing on a road course. Besides better performance and on a road course that means being able to rely on your brakes lap after lap, the pads are much thicker leading to far greater pad life. Also, you won’t have to worry about overheating and ruining piston ‘boots’, as they aren’t used.
There is a reason why AP Racing brakes on used on multiple series of race cars, and that’s because they are one of the best brake products made, and are multiples better than the OEM brakes found on our cars. Worth every penny if you track the car; not so much if you’re just hooning around canyons perhaps.
I've used AP Racing brake setups on all my old performance cars..
The thing I'm concerned with is stopping distance, hauling down a straight and late braking. Will it be a shorter shopping distance or will it be 5-10-20ft too long vs OEM at speed.
In other words which side of the wall will you be on when you really need to stop ?
Some guys are extra heavy on their brakes entering corners too hot scrubbing off too much speed and then complaining they need more power for corner exit. while others treat their cars as smooth momentum cars saving their brakes.
Until someone actually does real brake testing I'll stick with the OEM setup..
03-18-2020, 02:38 PM
