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Charger SRT 392
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Discussion Starter #1
For one piece rotor, the disc and hat are "casted" together with the same material (Cast Iron) after machined it's a finished product - like OEM so no concern on the rear drum brake because it has the same material as the disc.

A typical REAR one piece rotor with a DRUM brake. (Ford F150/Raptor)



However when it comes to making a "two piece rotor" for the rear like for Jeep SRT8 with a drum brake it's more challenging and tricky due to the hat must be made with a harder metal (Iron or Steel) in order to withstand the abrasiveness of the brake shoe like for one piece rotor, otherwise when a parking brake is applied, if you ever forget to release it before wheel is rolling, the brake shoe will "score" the aluminum drum hat and damage/ wear & enlarge the drum diameter then the brake shoe must be adjusted to fit the larger drum or the pedal travel distance will increase.

After a few more times the rotor hat wall material gets thinner eventually you rear rotor hat will be destroyed and you would lose the parking brake, not mention if you have to use it for emergency braking when driving!

This is why OE offers very few applications on rear for iron and for CCB rear stainless steel is used for for the rotor hats (eg. ZR1/Z28, PCCB). For aftermarket BBK (Brembo, AP, Stoptech) usually offers only front and very few on rear, or disclosing to "delete" the rear emergency/parking brake for installing their rear BBK. See the installation note on AP/Essex rear BBK for Supra MK5

RB developed a composite hat (aluminum shell + iron sleeve) and was first introduced in early 2000 for Camaro SS. The inner hat has an Iron liner - A true rear two piece rotor; light weight yet still retaining the functionality of OE emergency brake which is also a popular replacement to OE's stainless steel hat (can save 4 lbs/ea) for ZR1/Z28 OE CCM rear rotors.

Review on Corvette forum Make your rear CCM rotor lighter





If you don't disagree that safety is of the prime concern you should inquire the supplier if their rear two piece rotors are made for parking/emergency brake "functionality", not just to fit the brake shoe, before you buy and what they have sold you, otherwise you are better off to stay with OE or aftermarket one piece rotor.

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www.RacingBrake.com
 

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2020 Challenger Hellcat Redeye Wide Body
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Gotta love that last paragraph translation lol.
 
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2017 Daytona 392
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Heh, what's the rockwell hardness of aluminum compared to a typical cast iron rotor? ~70 C vs < 50 C? Unless you literally gouge the surface to expose the aluminum underneath, hard anodized 6061 works just fine for a hat.

Nevermind that some applications use non-anodized aluminum rotors, and research into the application is ongoing as recently as 2016.

One last thing for everyone's reference: where are TPM Products' (d.b.a. RacingBrake) products designed and made?
 

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designed here... made? Not sure

i have one of the BBKs on my 17 Vette with nearly zero issues. One hat replaced in 4 years.

GREAT product.
 

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Charger SRT 392
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Discussion Starter #6 (Edited)
Heh, what's the rockwell hardness of aluminum compared to a typical cast iron rotor? ~70 C vs < 50 C? Unless you literally gouge the surface to expose the aluminum underneath, hard anodized 6061 works just fine for a hat.

Nevermind that some applications use non-anodized aluminum rotors, and research into the application is ongoing as recently as 2016.

One last thing for everyone's reference: where are TPM Products' (d.b.a. RacingBrake) products designed and made?
Both Aluminum and cast iron use Brinell hardness scale not Rockwell.

This review on BMW forum may help better explain the hardness test on a rotor.

Why RacingBrake?/Why 2 Piece Rotors?

Most motor companies in their newer applications (~2015+) switched to dual functions' e-parking brake and eliminated the drum brake mainly for cost and weight saving, but it's only for good parking and NOT a substitute of emergency braking.

Check BMW and learn why only M3/M4 (motorsports models) still retain its drum brake while all other models (Including M5) have already converted to e-parking brake.

Why cheap rear brake calipers on M5 (and M8)?

"Design" and "Material" are the main topic of this thread, so let's keep your comment and opinion "objective".

We welcome other aftermarket brake mfgrs: Girodisc, DBA, R1, Powerstop, and Dodge/Jeep brake engineers to join the discussion here - Especially from Girodisc to explain their design, and why they use aluminum for the rear drum brake, and assure the Jeep owners OE's functional integrity w/o any concern. Maybe they have some exclusive "surface treatment" process etc. as you indicated, nevertheless I believe Jeep/Hellcat owners who have purchased their brake deserve a clarification and assurance from a responsible mfgr.

Warren-RB
 

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Charger SRT 392
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Discussion Starter #10
Webpage just updated to include the actual rotor assembly and other info - The template pic is for Camaro Z28 front (394x36mm)

Wt. saving (16 lbs per rotor, or 32 lbs per axle)

OE iron two piece rotor (390x34mm): 31 lbs
RB CCM rotors (Long carbon fiber): 15.1 lbs



The rotor kit comes with brake pad compound (XT600) for CCM rotors street plus driving, same combo as our offer for Mustang GT500 (420x40mm) upgrade.

Let us know how we can help.
 

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Discussion Starter #11
Pricey? - Let's factor in the initial buying and replacement costs, aside from the weight saving and performance improvement advantage.

OE two piece rotors $$?

RB CCM rotors are built made with continuous carbon fiber for extra strength and durability - Unlike OE (Viper ACRE) Brembo' chopped fibers which is very fragile to chip and break.
RB rotors are directional for improved cooling than Brembo's straight vanes.

Click link below to learn more detail.
 

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Pricey? - Let's factor in the initial buying and replacement costs, aside from the weight saving and performance improvement advantage.

OE two piece rotors $$?

RB CCM rotors are built made with continuous carbon fiber for extra strength and durability - Unlike OE (Viper ACRE) Brembo' chopped fibers which is very fragile to chip and break.
RB rotors are directional for improved cooling than Brembo's straight vanes.

Click link below to learn more detail.


Is that for one, or two, rotors?
 

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Have you seen that CDT Rotors are reported to be less than 12lbs each?
 

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Discussion Starter #14
Prices are in pair (1-Left; 1-Right); rotors are "directional" and we have no knowledge on those 12 lbs rotors.
 

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BTW, when I asked the rear hat "aluminum vs steel" question of DP/Girodisk, the answer I got was that the hat was aluminum and that if it was ever needed in an "emergency" that it should be replaced after any such incident. As for use as a Parking Brake, I have used mine (DP/Girodisk) on occasion but I've never driven with it "on", and I've taken my rear rotors off and inspected the condition of the Parking Brake friction surface.

All of the anodizing had been worn off by what could only be incidental contact of the Parking Brake shoe friction material, beyond that, I found no notable wear or issues.

My take on it is if you want the reduction in weight, then you live with what comes with the choice. While I understand the mentality of having the Parking Brake as an "Emergency" brake, in all of my years of driving, I have never known this to be a thing. Yes I still want it there, but I'm willing to live with the tiny risk associated with an aluminum hat and the need to replace it if I ever use it in that way.

As for driving around with the Parking Brake set, try real hard not to do that, ok?
 

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I'm curious about the heat dissipation. I have seen the thermal images of drilled rotors and then learned more about the dangers of the extreme heat difference between the area around the drilled hole and the rest of the rotor causing it to crack. For that reason I thought it was generally best to go with slotted rotors for the safety of the chance of them cracking, and the rapid disassembly of parts that would ensue.
 

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I'm curious about the heat dissipation. I have seen the thermal images of drilled rotors and then learned more about the dangers of the extreme heat difference between the area around the drilled hole and the rest of the rotor causing it to crack. For that reason I thought it was generally best to go with slotted rotors for the safety of the chance of them cracking, and the rapid disassembly of parts that would ensue.


I believe, and agree, that this applies to cast-iron rotors. CF likely can tolerate a much higher temperature delta?
 
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