Fixing SN-95 big brake bias: 14" 13-14 GT500 rear rotors on IRS + bias calculator for common brakes

[01yellercobra]

pretty sure FTBR offers a 13" rear setup fyi

They do! The downsides are that it requires their custom rotors and the cheapest version is $834! FTBR does make excellent stuff; my IRS has all of the FTBR stuff on it and it is awesome!

That's why I asked about the 13" option. He might be on to a more affordable option for those wanting bigger rear brakes.

If I'm reading the calculator right it's saying with the Baer 6P calipers and Taurus rear calipers to stick with the stock rear rotor size. But with the stock caliper to go to the 13.77" rotor. That's interesting. I have a set of Taurus calipers waiting to go on. But I'm still interested in the brackets.

 

[03HP]

That's why I asked about the 13" option. He might be on to a more affordable option for those wanting bigger rear brakes.

If I'm reading the calculator right it's saying with the Baer 6P calipers and Taurus rear calipers to stick with the stock rear rotor size. But with the stock caliper to go to the 13.77" rotor. That's interesting. I have a set of Taurus calipers waiting to go on. But I'm still interested in the brackets.

I did add a warning about the Taurus calipers to the top of the calculator page. There are quite a few posts about issues with them; I didn’t want it to suggest them to people without them being aware that some percentage of users are having problems!

I do think the GT500 rotors will require 18” wheels. If someone with stock wheels (also stock offset wheels) could confirm how close the caliper is for me, that would be very helpful! The bracket moves the caliper ~1” out radially (towards the wheel barrel) and ~3/4” outboard (towards the wheel face).

 

[vr4]

Interested

 

[GodStang]

I did add a warning about the Taurus calipers to the top of the calculator page. There are quite a few posts about issues with them; I didn’t want it to suggest them to people without them being aware that some percentage of users are having problems!

I do think the GT500 rotors will require 18” wheels. If someone with stock wheels (also stock offset wheels) could confirm how close the caliper is for me, that would be very helpful! The bracket moves the caliper ~1” out radially (towards the wheel barrel) and ~3/4” outboard (towards the wheel face).

My car has all stock stuff so I can measure today if need be. Just let me know what needs measured.

Also what is the issue with 43mm Taurus calipers? Was getting ready to switch to them to match up with my ATS front calipers.

 

[03HP]

My car has all stock stuff so I can measure today if need be. Just let me know what needs measured.

Also what is the issue with 43mm Taurus calipers? Was getting ready to switch to them to match up with my ATS front calipers.

The bracket moves the caliper ~1” out radially (towards the wheel barrel) and ~3/4” outboard (towards the wheel face). What’s the clearance stock in these directions? I’m pretty sure this requires 18” wheels but I’m double checking the offset.

On the Taurus calipers: I saw many reports of leaking pistons and some cases where the caliper completely locked up (including on track causing the car to roll). There was some speculation that the piston is worse quality metal that the Mustang calipers, the internal mechanisms were faulty, bad remans, etc. Scared me enough to add the warning on the calculator page.

 

[99cobrajn]

that calculator is awesome!! thanks!

 

[94slowbra1]

The biggest issue I see here is weight. What do these gt500 rotors weigh? I love the idea, as I love big brakes. I currently run the 14" brembo GT kit, basically the 14" FTBR kit. I want a bigger rear kit, however I don't want solid rotor due to weight. And something tells me switching to a 2pc rotor increases the price significantly.
Regardless, great work. Love seeing guys still coming up with ideas for these cars still, even at the 20yr mark.

 

[03HP]

The biggest issue I see here is weight. What do these gt500 rotors weigh? I love the idea, as I love big brakes. I currently run the 14" brembo GT kit, basically the 14" FTBR kit. I want a bigger rear kit, however I don't want solid rotor due to weight. And something tells me switching to a 2pc rotor increases the price significantly.
Regardless, great work. Love seeing guys still coming up with ideas for these cars still, even at the 20yr mark.

2 piece would significantly increase the cost. Centric lists Cobra rear rotors at 13 lbs and GT500 rotors at 16.8 lbs.

 

[03HP]

I heard back from the machine shop and I can sell these IRS adapters for $190 shipped. That includes the brackets, mounting hardware, and instructions. I assume these require 18" wheels.

To complete the install, you will need to source:
13-14 GT500 rear rotors ($32+ ea) (2013 FORD MUSTANG 5.8L V8 Supercharged Rotor | RockAuto)
03-04 Cobra rear pads ($13+ set) (2003 FORD MUSTANG 4.6L V8 Supercharged Brake Pad | RockAuto)

Please respond or DM me if you are serious about purchasing a set so I can order the right amount! Batch is being ordered 6/26!



I have also designed (and run stress analysis on) SRA adapters for cars with GT or Cobra brakes that are the same price ($190 shipped). I have someone with GT brakes and someone with Cobra brakes confirming fitment of these adapters as I don't have a SRA car. If a car has GT brakes, you will also need to source 03-04 Cobra caliper brackets to fit the wider vented rotor ($22+ ea) (2003 FORD MUSTANG 4.6L V8 Supercharged Caliper Bracket | RockAuto)

Please respond or DM me if you want to be notified once these are tested!

 

[vr4]

I'm down for a set of irs adapters.

 

[Onslaught 001]

I have also designed (and run stress analysis on) SRA adapters for cars with GT or Cobra brakes that are the same price ($190 shipped). I need someone with GT brakes and someone with Cobra brakes to confirm fitment of these adapters as I don't have a SRA car. If a car has GT brakes, you will also need to source 03-04 Cobra caliper brackets to fit the wider vented rotor ($22+ ea) (2003 FORD MUSTANG 4.6L V8 Supercharged Caliper Bracket | RockAuto)

Please respond or DM me if you are serious about purchasing and testing the adapters on a SRA car!

03HP, found this thread by way of FB. I have a solid axle car equipped with M-2300-K, the 11.65" brake setup for the rear. I would interested in testing your brackets.

Fwiw, I already have on the shelf the FTBR 13" rear rotors and brackets. The brackets are steel, plated. FTBR did some neat tricks using their rotor to offset differently to make room for the bracket. I stopped using this setup on the solid axle because it lacks stiffness. The rotor tended to rub the inside of the caliper bracket. Note the axle flange floats inward/outward within the tolerance of the c-clips in the carrier. Photo.

I'm also in the process of fitting GT1/F40/F50 calipers to the front with Gt500 rotors. Photo.

Your build thread is providential.

 

[03HP]

03HP, found this thread by way of FB. I have a solid axle car equipped with M-2300-K, the 11.65" brake setup for the rear. I would interested in testing your brackets.

Fwiw, I already have on the shelf the FTBR 13" rear rotors and brackets. The brackets are steel, plated. FTBR did some neat tricks using their rotor to offset differently to make room for the bracket. I stopped using this setup on the solid axle because it lacks stiffness. The rotor tended to rub the inside of the caliper bracket. Not the axle flange floats inward/outward within the tolerance of the c-clips in the carrier. Photo.

I'm also in the process of fitting GT1/F40/F50 calipers to the front with Gt500 rotors. Photo.

Your build thread is providential.

Awesome car! I DM’d you with more details!

 

[leecar83]

I'm in for a set of IRS adapters. New to the forum so don't have DM privileges yet; you can email me:
leecar83 at hotmail dot com

 

[Blkkbgt]

On the Taurus calipers: I saw many reports of leaking pistons and some cases where the caliper completely locked up (including on track causing the car to roll). There was some speculation that the piston is worse quality metal that the Mustang calipers, the internal mechanisms were faulty, bad remans, etc. Scared me enough to add the warning on the calculator page.

Here's my experience with a set of Taurus calipers. Post 941.

Installing ATS Brembos on the Cobra.

I am going to preface this by stating I am pist the **** off right now! I finally pulled apart my cardone calipers this afternoon trying to pull out a small victory on my car. I fully disassembled my R/H caliper first and what I found was shocking. The bore that accepts the parking brake...

www.svtperformance.com

Based on what I found I think the calipers are simply sitting on the shelf to long.

The sitting is causing corrosion and dried out seals.

I don’t think the piston material is any different than the mustang calipers or of a lower quality.

I think the corrosion is causing the parking brake mechanism to malfunction.

 

[03HP]

Here's my experience with a set of Taurus calipers. Post 941.

Installing ATS Brembos on the Cobra.

I am going to preface this by stating I am pist the **** off right now! I finally pulled apart my cardone calipers this afternoon trying to pull out a small victory on my car. I fully disassembled my R/H caliper first and what I found was shocking. The bore that accepts the parking brake...

www.svtperformance.com

Based on what I found I think the calipers are simply sitting on the shelf to long.

The sitting is causing corrosion and dried out seals.

I don’t think the piston material is any different than the mustang calipers or of a lower quality.

I think the corrosion is causing the parking brake mechanism to malfunction.

Seems like the most obvious cause!

 

[Blkkbgt]

Seems like the most obvious cause!

I agree but I am basing my conclusions off of 1 set of calipers.

Since I am committed to the ATS swap at this point I will be getting another set from a local parts store.

I'll disassemble those as well and report my findings.

At an absolute minimum I think everyone should pull theirs apart to replace the seals and make sure the parking brake mechanism works properly.

 

[01yellercobra]

I'm in for the brackets.

I'm going to tear apart my Taurus calipers for powder coating anyway. I'll throw new seals in while I'm there.

 

[03HP]

I'm in for the brackets.

I'm going to tear apart my Taurus calipers for powder coating anyway. I'll throw new deals in while I'm there.

I’ll send you a DM! Just to re-iterate the clearance notes for everyone: The bracket moves the caliper ~1” out radially (towards the wheel barrel/tire) and ~3/4” outboard (towards the wheel face). Both directions could be an issue depending on your wheels.

 

[MickeyDs]

I am in for a bracket as well!

 

[03HP]

I am in for a bracket as well!

DM sent!