Larger Rear Brake Rotors?

[NWBoss]

Stoptech has a bunch of good tech articles and here's one on rear rotor size.

http://www.stoptech.com/technical-support/technical-white-papers/rear-brake-upgrades

http://www.stoptech.com/technical-support/technical-white-papers

This is a really excellent resource! Gave me enough reading material for a few days.

 

[Grant 302]

Turns out there is an example of going to far on the rear brakes. I overheard friend with a Wilwood 6 piston front and 4 piston rear talking about what he was doing to correct for too much rear brake bias. He machined the rear pads to what sounded like half the surface area. ??? I was just leaving so I didn't get to discuss it much. I'd like to hear more about how bad it was on track - I'll ask next time I see him.

I do wonder if it is also the reason why the early '11 Brembo GT literature said 2 piston rears...maybe they were in the program but got cut from actual test/track results instead of the typographical error some of us assumed.

The good news is this shouldn't alarm anyone about any stock caliper or maybe even 2 piston upgrades. Going from the stock diameter to Steeda or GT500 rears would only increase brake torque by ~10 or ~17%. That's relatively small compared to the ~100%? increase from a 4 piston rear while only increasing the front ~50%.

For those checking my math, I am assuming no difference in braking force when comparing a single pot to the same size opposing 2 pot.

 

[neema]

Just saw this not too long ago: https://www.facebook.com/photo.php?fbid=821608257855044&set=a.212454705437072.67414.212452725437270&type=1&theater

Don't know if Facebook links work, but Cortex came up with a Brembo 4 piston GT caliper to work. Lots of work goes into it though. Definitely not in my price point. Ever

 

[VoodooBoss]

Before I bought my Stoptech kit from Cortex I researched this a lot and came to the conclusion that Brembo replacement rings are a LOT more expensive than Stoptech and other two piece rotor suppliers.

 

[lbp]

Playing devils advocate...if it's advised to not upset the braking bias then why is it routinely recommended to use a less aggressive pad in the rear when upgrading to track pads on a stock setup? Isn't the front and rear stock pad compound the same? If the logic of keeping everything in line holds true then wouldn't we want to run identical track compounds in the front and rear (with stock caliper/rotor setup)?

I realize that too much braking force in the rear is not good, but if the goal is to reduce the temperature in the rear it seems like going with a larger rotor paired with a less aggressive pad (vs the front) would balance things out.

I've been running carbotech xp20's on stock fronts and XP12's on the GT500 rotors for the past year and have not had any problems under extreme braking. This topic has got me wondering so I wanted to think this through out loud to see if I'm making any sense. It seems logical but then again, I wasn't too kind to my brain cells during my youth

Tuning w/pads is an option but as temps increase, other things may come into the picture

 

[KBBOSS1086]

I've ran Carbotech XP16's on the front (stock Boss setup) with Hawk HPS in the rear (GT500 rotors) for a few events now and have had no issues. Braking is very good and she stays in a straight line. I do use some trail and left foot braking on certail tracks / turns and I have not found that the GT500 rotors cause over rotation or issues.

Prior to switching to the GT500 rear rotors I ran Carbotech XP10's with the XP16's in the front and would often experience some tail wag under heavy braking at the end of high speed straights. FWIW I'm pretty confident that the GT500 rear rotors work very well as long as you have less aggressive pad out back. I almost feel like the rear braking is so insignificant in our cars that you could remove the calipers entirely and still get around the track safetly and fast. ???

I will be running Hawk DTC-60's up front with the HPS's in the rear at my next event. I don't expect any issues, but if I do experience a problem I will report back.

 

[VoodooBoss]

It now looks like aftermarket replacement rotors are showing up for the 13/14 GT500 brake kits. Stoptech:

http://www.lethalperformance.com/stop-tech-2013-2014-shelby-gt500-high-carbon-slotted-rear-brake-rotor-right.html

http://www.lethalperformance.com/stop-tech-2013-2014-shelby-gt500-high-carbon-slotted-front-brake-rotor-left.html

 

[Wingrider]

It now looks like aftermarket replacement rotors are showing up for the 13/14 GT500 brake kits. Stoptech:

That looks strangely familiar… ;-)

 

[ArizonaBOSS]

I like how the stock photos are for something not Mustang at all.

 

[KNS Brakes]

It now looks like aftermarket replacement rotors are showing up for the 13/14 GT500 brake kits. Stoptech:

http://www.lethalperformance.com/stop-tech-2013-2014-shelby-gt500-high-carbon-slotted-rear-brake-rotor-right.html

http://www.lethalperformance.com/stop-tech-2013-2014-shelby-gt500-high-carbon-slotted-front-brake-rotor-left.html

We've had these listed on our site for quite some time. I think Stoptech introduced them around Feb. I actually keep them in stock.

I like how the stock photos are for something not Mustang at all.

It would take a lot of time to photograph every single part for every single car. General pictures are the best way to get the point across on what the part "generally" looks like.

-Nick

 

[VoodooBoss]

From another thread:

Installed the GT500 13.8" rear brakes. I used the Baer bracket 670-0183, (which is really an adapter bracket to push out the caliper about an inch) so I did not have to remove the caipers, or axles to do the install. No bleeding of the brakes or diff oil needed. The bracket cost was $85 each plus shipping from Baer in Arizona. Oh, you will need to get 4 bolts, M12 X 55mm long (I used 60mm, as that was all I could find).

Here is a picture with the Baer bracket installed. (of course it is the black one)

Before picture of the 11.8" rear brakes.

After picture of the 13.8" GT500 brakes.

After picture with Boss 19" wheel.

After picture with my GT500 20" wheel.

These brackets are the ones that come in the 14" Baer rear brake kit 226-2019. The GT500 Rotors are slightly smaller at 13.8", and therefore the brake pads are located right at the outer edge of the rotor. I hope this is not going to be an issue.

Here is a picture of the pad to rotor. (Pad extends about a 1/16th past the rotor)

I am going to try and get the 15" GT500 front brakes installed in the next couple weeks. They will involve bleeding the brakes.

 

[ArizonaBOSS]

That seems like the most inexpensive and painless option to get this done!

 

[RR2334]

Exactly why I did it. Just add the cost of 2 GT500 stock rotors from a 2013/14 with a 13.8" diameter and do it on your driveway in about 30 to 60 mins.

 

[Jabooh]

Have you had an issue with the pad sitting at the edge of the rotor?

 

[VoodooBoss]

That seems like the most inexpensive and painless option to get this done!

Exactly. If I go this route I'll use the Stoptech GT500 rear rotors with slots, that KNS Brakes sells, to match my fronts.

 

[RR2334]

Have you had an issue with the pad sitting at the edge of the rotor?

The pad is about 1/16th outside the edge of the rotor. I don't think it will be an issue.

 

[RR2334]

Exactly. If I go this route I'll use the Stoptech GT500 rear rotors with slots, that KNS Brakes sells, to match my fronts.

Do you have a coupon code to save a few bucks on the rotors??

Don't worry about it I just found a couple.

 

[Jabooh]

There is a guy on SVTP "ncmustangparts" who sells brackets as well. $145 for both.
http://www.svtperformance.com/forums/showthread.php?1047921-FS-14-quot-brake-caliper-adapter-brackets

Haven't bought yet but plan too. Specifically made to work with the 13/14 GT500 rear rotors.

 

[302 Hi Pro]

Did not know about these special purpose caliper brackets when I did my GT500 rear rotors, so I went with the OEM brackets. Worked on and serviced the rear diff at the same time and also installed new brake lines.

It was also nice to learn the 2013/14 GT500's use the Boss 302 rear calipers. This is a nice brake upgrade that adds additional rotor surface area to dissipate heat a bit better. With Dot 4 fluid and the new brake lines, the brakes feel great and they have excellent modulation. You'll like the result and know that it's worth taking the extra time to install OEM relo brackets.

Good luck with your upgrade,

Dave
302 Hi Pro

 

[Grant 302]

There is a guy on SVTP "ncmustangparts" who sells brackets as well. $145 for both.
http://www.svtperformance.com/forums/showthread.php?1047921-FS-14-quot-brake-caliper-adapter-brackets

Haven't bought yet but plan too. Specifically made to work with the 13/14 GT500 rear rotors.

He also has them on eBay.